Oxidative carbon-carbon bond cleavage is a key step in spiroacetal biosynthesis in the fruit fly Bactrocera cacuminata

Article abstract of DOI:10.1021/jo500791y

The early steps of spiroacetal biosynthesis in the fruit fly Bactrocera cacuminata (Solanum fly) have been investigated using a series of deuterium-labeled, oxygenated fatty acid like compounds. These potential spiroacetal precursors were administered to male flies, and their volatile emissions were analyzed for specific deuterium incorporation by GC/MS. This has allowed the order of early oxidative events in the biosynthetic pathway to be determined. Together with the already well-established later steps, the results of these in vivo investigations have allowed essentially the complete delineation of the spiroacetal biosynthetic pathway, beginning from products of primary metabolism. A fatty acid equivalent undergoes a series of enzyme-mediated oxidations leading to a trioxygenated fatty acid like species that includes a vicinal diol. This moiety then undergoes enzyme-mediated oxidative carbon-carbon bond cleavage as the key step to generate the C₉ unit of the final spiroacetal. This is the first time such an oxidative transformation has been reported in insects. A final hydroxylation step is followed by spontaneous spiro-cyclization. This distinct pathway adds further to the complexity and diversity of biosynthetic pathways to spiroacetals.

Full text of DOI:10.1021/jo500791y

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pubs.acs.org/joc
Oxidative Carbon−Carbon Bond Cleavage Is a Key Step in
Spiroacetal Biosynthesis in the Fruit Fly Bactrocera cacuminata
Arti A. Singh, Jessica A. Rowley, Brett D. Schwartz, William Kitching, and James J. De Voss*
School of Chemistry and Molecular Biosciences, University of Queensland, Brisbane 4072, Australia
*
S Supporting Information
ABSTRACT: The early steps of spiroacetal biosynthesis in
the fruit fly Bactrocera cacuminata (Solanum fly) have been
investigated using a series of deuterium-labeled, oxygenated
fatty acid like compounds. These potential spiroacetal
precursors were administered to male flies, and their volatile
emissions were analyzed for specific deuterium incorporation
by GC/MS. This has allowed the order of early oxidative
events in the biosynthetic pathway to be determined. Together with the already well-established later steps, the results of these in
vivo investigations have allowed essentially the complete delineation of the spiroacetal biosynthetic pathway, beginning from
products of primary metabolism. A fatty acid equivalent undergoes a series of enzyme-mediated oxidations leading to a
trioxygenated fatty acid like species that includes a vicinal diol. This moiety then undergoes enzyme-mediated oxidative carbon−
carbon bond cleavage as the key step to generate the C unit of the final spiroacetal. This is the first time such an oxidative
9
transformation has been reported in insects. A final hydroxylation step is followed by spontaneous spiro-cyclization. This distinct
pathway adds further to the complexity and diversity of biosynthetic pathways to spiroacetals.
INTRODUCTION
penultimate carbon hydroxylation step but display species-
■
specific differences in their early steps and in the origin of the
The spiroacetal motif is found within many natural products
isolated from terrestrial and marine, prokaryotic and eukaryotic
sources. Simple spiroacetals are common in insects of the
orders Diptera (true flies), Hymenoptera (wasps, ants, and
bees) and Coleoptera (beetles) and are usually found as
1
8
oxygen atoms of 2. O- and deuterium-labeling studies
indicated that while all three pathways involve the oxidation
of long-chain fatty acid equivalents (e.g., fatty acids or
thioesters) to produce a common intermediate, 2,6-undecane-
dione (3), the sequence of steps that leads to 3 is distinctly
1
components of volatile semiochemical secretions. 1,7-
1
,4−7
Dioxaspiro[5.5]undecane (1) was the first spiroacetal to be
identified as an insect sex pheromone when it was isolated as
the major component of the blend emitted by female Bactrocera
different in each species.
Despite this, the steps from 3 to
4
,6,7
spiroacetal 2 are identical in all three species.
The derivation
of at least one oxygen atom of 2 from O suggested the
2
2
oleae (Olive fly). Over 30 structurally different spiroacetals,
involvement of the oxidative cytochrome P450 enzymes
(P450s) in these biosynthetic pathways.
Only the later stages of the biosynthesis of the unsubstituted
including hydroxylated and alkylated ones, have since been
discovered and characterized, with disubstituted 2 being most
commonly observed in nature. While these deceptively simple
structures have received a great deal of synthetic attention,
1
C spiroacetal 1 in female B. oleae and male B. cacuminata
9
1
−3
(
Solanum fly) are well established and bear a strong
relatively little is known about their biosynthesis. Under-
standing sex pheromone biogenesis may form the basis for
species-specific methods of pest control, and thus, there is
interest in the biochemical origin of spiroacetals. Their
biosynthesis in Bactrocera sp. has been investigated because of
the highly pestiferous nature and economic importance of B.
oleae and B. tryoni (Queensland fruit fly). Studies to date with
these and other insects have indicated a surprising degree of
complexity and diversity in the construction of such simple
molecules.
resemblance to those in the biosynthesis of 2 (Scheme 1).
The biogenesis of 1 (Scheme 2) has so far proven to be
identical in both species. 5-Hydroxynonanal (4) undergoes
8
reduction to form 1,5-nonanediol (5), which is then oxidized at
9
C-9 (ω oxidation) to give 1,5,9-nonanetriol (6). Further
oxidation of triol 6 affords meso ketodiol 7, which cyclizes to
afford spiroacetal 1 as a racemate. Hydroxyspiroacetals formed
5
,10
by oxidation of 1 have been detected in both species. These
results have led to the proposal of a general paradigm for
spiroacetal biosynthesis that appears to be applicable across
insect genera: generation of a dioxygenated precursor via the
oxidation/modification of a long chain fatty acid equivalent is
4
The major spiroacetal produced by female B. tryoni, male B.
5
cucumis (Cucumber fly), and female Megarhyssa nortoni nortoni
6
(
Giant Ichneumon Wasp) is (E,E)-2. Isotopic labeling studies
with these species have led to the delineation of three distinct,
yet related, biosynthetic pathways to 2 from primary
Received: April 8, 2014
1
,4−7
metabolites.
These pathways (Scheme 1) all involve a
©
XXXX American Chemical Society
A
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Scheme 1. Biosynthesis of Spiroacetal 2 in M. nortoni nortoni, B. cucumis, and B. tryoni, Showing the Origin of the Oxygen
1
,4−7a
Atoms
a
“Pro C-2” refers to the carbon atom of the fatty acid equivalent that becomes C-2 of 2,6-undecanedione (3) and subsequently C-2 (or C-10) of
spiroacetal 2, and “pro C-6” refers to the carbon atom that becomes C-6 of 3 and subsequently the spirocenter of 2.
Scheme 2. Established Later Steps in the Biosynthesis of
Spiroacetal 1 in B. cacuminata and B. oleae, Showing the
5
−8,10
Origin of the Oxygen Atoms
Figure 1. Synthetic targets in unlabeled form.
followed by carbon hydroxylation and cyclization of a resultant
6
,7
ketodiol as the final step.
10
Both oxygen atoms in 1 are derived from O in B. oleae and
2
5
B. cacuminata (cf. spiroacetal 2 in B. tryoni), indicating that the
are negatively charged) at biological pH and are unable to cross
biological membranes easily. Thus, methyl esters or lactones
were synthesized and administered in order to promote
successful passage of the compounds across cell membranes
and to render them accessible to enzymes in vivo. While fatty
acid metabolizing P450s often have preferred substrate chain
C unit of 1 does not come directly from a fatty acid or
9
polyketide biosynthetic pathway. This strongly suggests the
involvement of P450s in the generation of 4 from a long-chain8
fatty acid equivalent in these species. It was thus hypothesized
that 4 arose within these flies via P450-mediated oxidative
carbon−carbon bond cleavage of a saturated chain. The
majority of research into insect P450s to date has focused on
their roles in xenobiotic metabolism (especially insecticide
metabolism), although it has been suggested that approximately
1
2,13
lengths,
the chain length specificity of the spiroacetal
biosynthetic enzymes of B. cacuminata and B. oleae has not yet
been investigated. The C14 chain length employed here was
chosen because it was thought that longer chain lengths, closer
to dietary fatty acids, might be more susceptible to catabolism
3
5−50% of P450s found within an insect species are likely to be
11
involved in hormone and pheromone production.
by processes such as β-oxidation.
2
Herein, we describe our investigations into the early steps of
the biosynthetic pathway of spiroacetal 1 in male B. cacuminata,
specifically focused on the involvement and stereoselectivity of
the proposed oxidative C−C bond cleavage step.
A series of stereoisomeric dihydroxylactones [ H ]-8/
4
2
trihydroxyesters [ H ]-9 (biosynthetically equivalent to trihy-
4
droxy-fatty acids) with defined vicinal diol stereochemistry was
used to probe the involvement and stereoselectivity of an
oxidative C−C bond cleavage step. Based on the results of
feeding experiments with these compounds (vide infra), several
RESULTS AND DISCUSSION
■
2
2
2
Several oxygenated fatty acid like compounds (Figure 1) were
synthesized in deuterium-labeled form to investigate the
biosynthetic steps that lead to the formation of 5-
hydroxynonanal (4) and, thus, spiroacetal 1, in male B.
cacuminata. Carboxylic acids exist in their ionized form (i.e.,
compounds with dioxygenated ([ H ]-10, [ H ]-11, and [ H ]-
4 4 2
2
2
2
12) and monooxygenated chains ([ H ]-13, [ H ]-14, [ H ]-
15, and [ H ]-16) were also synthesized and employed to
4
4
4
2
4
investigate the order of oxidative events that lead to the
formation of a trioxygenated chain species.
B
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2
Synthesis of Compounds with Trioxygenated Chains.
Compound 17 was the key intermediate in the construction of
the isomeric 6,10-dihydroxylactones 8/5,6,10-trihydroxyesters
Threo Isomers. Synthesis of threo [ H ]-(S,S)-8/9 and
4
2
[ H ]-(R,R)-8/9 then commenced with lithium/liquid ammo-
4
nia-mediated reduction of 17 (Scheme 4). This converted the
alkyne to the desired (E)-alkene and simultaneously removed
the benzyl ether to afford (E)-23 in 93% yield. Elaboration of
(E)-23 via a series of standard transformations including base-
catalyzed deuterium exchange then afforded the δ,ε-(E)-
unsaturated hydroxyester [ H ]-(E)-27 in good yield over five
9
, both in deuterium-labeled and unlabeled form. The alkyne
moiety of 17 allowed formation of both (E)- and (Z)-alkenes,
which were required for the stereoselective introduction of the
5,6-threo or erythro vicinal diol moieties; the protected alcohols
2
at C-1 and C-10 were subsequently transformed into the
desired ester and ketone functionalities, respectively. The
ketone at C-10 allowed for regiospecific deuterium-labeling via
base-catalyzed exchange and its chemoselective reduction
provided the desired C-10 hydroxyl group; the stereochemistry
of this is currently believed to be unimportant and thus was not
controlled. Introduction of the threo or erythro vicinal diol
moieties via osmium-mediated oxidation was initially envi-
sioned as the final synthetic step.
4
15
2
steps. Sharpless’ asymmetric dihydroxylation (SAD) of [ H ]-
4
2
2
(
(
E)-27 then gave the threo diols [ H ]-(S,S)-8/9 and [ H ]-
4
4
2
2
R,R)-8/9. Dihydroxylactones [ H ]-(S,S)-8 and [ H ]-(R,R)-8
presumably arose from the in situ lactonization of the initially
formed trihydroxyesters [ H ]-(S,S)-9 and [ H ]-(R,R)-9.
4
4
2
2
4
4
However, difficulties were encountered in the purification and
isolation of 8/9, attributed to ring-opening or hydrolysis of 8
during work-up and/or chromatographic purification. An
alternative synthetic route that circumvented these difficulties
was thus developed.
Enantioselective dihydroxylation was again the key step, but
the vicinal diol was introduced early during the synthesis and
protected as the corresponding isopropylidene ketal. It was
envisioned that acid-catalyzed cleavage of the ketal as the final
synthetic step would produce only a volatile byproduct and
would circumvent the requirement for chromatographic
purification. Alkene (E)-23 was thus reacted with either AD-
mix-α or AD-mix-β (Scheme 5) under standard SAD
conditions to form (5S,6S)- and (5R,6R)-diol moieties,
Alkyne 17 was obtained by coupling of the anion of THP-
7
protected 5-hexyn-1-ol (18) and benzyl-protected 1-iodooc-
tan-4-ol (19). The synthesis of iodide 19 commenced with
14
racemic 1-octen-4-ol (20), the hydroxyl group of which was
easily protected as the benzyl ether to give 21 in 84% yield
(
Scheme 3). Hydroboration−oxidation of 21 afforded the
Scheme 3. Synthesis of 17 from 1-Octen-4-ol (20) and
a
Alkyne 18
15
respectively, based upon the Sharpless predictive model.
Both the desired 5,6,10-triols (S,S)-28 and (R,R)-28 were
obtained in 95% yield, thus providing the 1,5,6,10-tetraoxy-
genated C14 skeleton required for the subsequent formation of
16
the 5,6-threo isomers of 8/9.
Synthesis of the desired (S,S)- and (R,R) compounds, threo-
8/9, was then carried out in parallel using identical method-
ology. Acid-catalyzed THP-deprotection of threo-28 cleanly
afforded the tetraol threo-29 in excellent yield (Scheme 5), and
the vicinal diol moiety was selectively protected as an
isopropylidene ketal, threo-30. Oxidation (PDC, DMF) of
threo-30 to the ketoacid threo-31 and subsequent esterification
a
Reagents and conditions: (a) (i) NaH, THF, 0 °C, (ii) BnBr, tetra-n-
butylammonium iodide, rt, 84%; (b) (i) BH ·DMS, CH Cl , 0 °C, (ii)
NaOH, H O , rt, 87%; (c) I , PPh , imidazole, CH CN/Et O (1:3), 0
3
2
2
2
2
2
3
3
2
°
−
C to rt, 98%; (d) (i) n-BuLi, THF, −40 °C, (ii) HMPA, iodide 19,
40 °C to rt, 83%.
primary alcohol 22 (87% yield), which was subsequently
converted to the desired iodide 19 (I , PPh , imidazole, 98%
(CH N , MeOH/Et O) provided the ketoester threo-32 in high
2 2 2
yield. Enantioselective HPLC analysis (Chiralpak OD column)
revealed an enantiomeric excess (ee) of 84% for (S,S)-32 and
81% for (R,R)-32, in accord with ee values reported for similar
2
3
yield). The terminal alkyne 18 was then deprotonated (n-BuLi,
40 °C), and the resulting anion was reacted with iodide 19 in
the presence of HMPA to afford the key intermediate 17 in
3% yield.
−
1
7,18
systems in the literature.
Chemoselective ketone reduction
8
of threo-32 then afforded the hydroxyester threo-33 with
2
2
a
Scheme 4. Initial Synthetic Route to Threo Compounds [ H ]-(S,S)-8/9 and [ H ]-(R,R)-8/9 from 17
4
4
a
Reagents and conditions: (a) Li (s)/NH (l), t-BuOH/THF (3:5), −78 °C, 93%; (b) p-TsOH, MeOH, 94%; (c) Jones’ reagent, acetone, 0 °C to rt,
3
2
9
5%, ≥95% E isomer; (d) LiOD, D O/THF; (e) CH N , MeOH/Et O, 0 °C to rt, 62% over two steps, ≥95% E isomer, ≤1% [ H ]; (f) (i) NaBH ,
2
2
2
2
0
4
2
2
MeOH, 0 °C to rt, (ii) chromatography with AgNO -impregnated silica gel, 87%, 100% E isomer, ≤1% [ H ]; (g) [ H ]-(S,S)-8/9: AD-mix-α,
MeSO NH , t-BuOH/H O (1:1), 0−4 °C, 2%; [ H ]-(R,R)-8/9: AD-mix-β, MeSO NH , t-BuOH/H O (1:1), 0−4 °C, 6%.
3
0
4
2
2
2
2
4
2
2
2
C
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a
Scheme 5. Optimized Synthetic Route to Unlabeled Threo Compounds (S,S)-8/9 and (R,R)-8/9 from Compound (E)-23
a
Reagents and conditions: (a) (S,S)-28: AD-mix-α, MeSO NH , t-BuOH/H O (1:1), 0−4 °C, 95%; (R,R)-28: AD-mix-β, MeSO NH , t-BuOH/
2
2
2
2
2
2
H O (1:1), 0−4 °C, 95%; (b) HCl, MeOH, (S,S)-29 96%; (R,R)-29 95%; (c) p-TsOH, acetone, 4 Å molecular sieves, (S,S)-30 97%; (R,R)-30 94%;
(
d) PDC, DMF, (S,S)-31 91%; (R,R)-31 95%; (e) CH N , MeOH/Et O, 0 °C to rt, (S,S)-32 94%, 84% ee; (R,R)-32 95%, 81% ee (Chiralpak OD
2
2
2
−
1
column, 2% 2-propanol in n-hexane, flow rate 0.8 mL min , PDA-UV detector 215 nm, retention times: (R,R)-32 10.8 min, (S,S)-32 11.2 min); (f)
NaBH , MeOH/Et O, 0 °C to rt, (S,S)-33 93%; (R,R)-33 93%; (g) Amberlyst 15 acidic resin, MeOH/THF, 70 °C; (h) CH N , MeOH/Et O,
4
2
2
2
2
(S,S)-8/9 ∼95%; (R,R)-8/9 ∼91%.
uncontrolled stereochemistry at C-10. Methanolysis of the
ketals catalyzed by acidic Amberlyst 15 ion-exchange resin at 70
Scheme 6. Synthesis of Deuterium-Labeled Threo
2
2
Compounds [ H ]-(S,S)-8/9 and [ H ]-(R,R)-8/9 from
4
4
1
9−21
a
°C
and treatment of the crude products with diazo-
methane afforded mixtures of the desired dihydroxylactones
S,S)-8 or (R,R)-8 and their corresponding methyl trihydrox-
Ketoacids (S,S)-31 and (R,R)-31
(
yesters (S,S)-9 or (R,R)-9 in excellent yields.
The final deprotection step worked well and no further
purification was required, eliminating the earlier problems
experienced with chromatography. The presence of both
dihydroxylactone 8 and trihydroxyester 9 in each product
mixture was confirmed by NMR spectroscopy and mass
spectrometry, where [M + Na]+ ions for both 8 (m/z 281)
and 9 (m/z 313) were detected. The H and C NMR spectra
of the products were complicated due to the presence of the
diastereomeric dihydroxylactones 8, trihydroxyesters 9, and
what appears to be the corresponding trihydroxy acids 34
a
Reagents and conditions: (a) NaOD, D O/THF; (b) CH N ,
2
2
2
•
2
MeOH/Et O, 0 °C to rt, [ H ]-(S,S)-32 91% over two steps, ≤1%
2
4
1
13
2
2
2
[ H ]; [ H ]-(R,R)-32 93% over two steps, ≤1% [ H ]; (c) NaBH ,
0
4
0
4
]-
2
2
2
MeOH/Et
O, 0 °C to rt, [ H
]-(S,S)-33 97%, ≤1% [ H ]; [ H
0 4
2
4
2
(
R,R)-33 98%, ≤1% [ H ]; (d) Amberlyst 15 acidic resin, MeOH/
0
2
THF, 70 °C; (e) CH N , MeOH/Et O, [ H ]-(S,S)-8/9 ∼96%, ≤1%
2
2
2
4
2
2
2
[
H ]; [ H ]-(R,R)-8/9 ∼92%, ≤1% [ H ].
0
4
0
(
Figure 2) generated over the course of spectral acquisition.
Synthesis of the deuterium-labeled analogues of threo-8/9
was then undertaken via an analogous route (Scheme 6).
Ketoacids (S,S)-31 and (R,R)-31 were thus treated with
NaOD/D O, which resulted in H−D exchange adjacent to
2
2
the C-10 ketone moiety. Esterification afforded [ H ]-(S,S)-32
and [ H ]-(R,R)-32 in 91% and 93% yields over two steps,
4
2
4
Figure 2. (5S,6S)-5,6,10-Trihydroxytetradecanoic acid [(S,S)-34] and
its corresponding sodium carboxylate (S,S)-35.
respectively. NMR and GC/MS analysis confirmed the almost
complete, regiospecific deuteration at C-9 and C-11 (≤1%
2
[
H ]) and established the tetradeuterated species as the
0
However, only dihydroxylactones 8 were observed by GC/MS
analysis in both cases, presumably due to intramolecular
cyclization of 9 promoted by the high temperature within the
GC injection port. Compounds 8 and 9 are equivalent in terms
of being potential precursors to spiroacetal 1 in B. cacuminata
and should cross cell membranes to the biosynthetic enzymes
in vivo. A small amount of the (S,S) product mixture was
predominant products. Subsequent ketone reduction and acid-
catalyzed ketal methanolysis afforded the desired dihydrox-
2
2
ylactone/trihydroxyester mixtures [ H ]-(S,S)-8/9 and [ H ]-
4
4
(R,R)-8/9 in high yields. GC/MS and NMR spectroscopy
confirmed the retention of deuterium throughout this series of
+
•
transformations. ESI mass spectrometry gave [M + Na] ions
2
for both the dihydroxylactones [ H ]-threo-8 (m/z 285) and
4
2
treated with NaOD in D O in order to convert all of the
trihydroxyesters [ H ]-threo-9 (m/z 317).
2
4
diastereomeric tetraoxygenated compounds present into the
Erythro Isomers. The synthesis of erythro dihydroxylac-
tones 8/trihydroxyesters 9 commenced with catalytic hydro-
genation of 17 over Lindlar’s catalyst (Scheme 7), which gave
the desired alkene (Z)-36 in 84% yield without affecting the
benzyl ether at C-10. On occasion, GC/MS and NMR analysis
of (Z)-36 revealed that a small amount (∼10%) of the
corresponding chromatographically inseparable (E)-alkene (E)-
36 had also been formed during the catalytic hydrogenation of
single, diastereomeric sodium carboxylate (S,S)-35 (Figure 2).
1
13
The H and C NMR spectra of (S,S)-35 were much simpler,
13
with only two sets of resonances now observed in the C NMR
spectrum for C-5, C-6 and C-10, and a single signal present for
C-1 (carboxylate carbon). This confirmed that the original
product mixture was comprised only of pairs of equivalent
tetraoxygenated compounds diastereomeric at C-10.
D
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a
Scheme 7. Synthesis of Unlabeled erythro-8/9 from Compound 17 via (Z)-36
a
Reagents and conditions: (a) H , Lindlar’s catalyst (5% Pd/CaCO poisoned with lead), EtOAc, 84%; (b) OsO , NMO, THF/t-BuOH/H O
2
3
4
2
(
10:3:1), 90%; (c) p-TsOH, MeOH, quantitative; (d) H , 10% Pd/C, MeOH, 97%; (e) p-TsOH, acetone, 4 Å molecular sieves, 97%; (f) PDC,
2
DMF, 89%; (g) CH N , MeOH/Et O, 0 °C to rt, quantitative; (h) NaBH , MeOH/Et O, 0 °C to rt, 94%; (i) Amberlyst 15 acidic resin, MeOH/
2
2
2
4
2
THF, 70 °C; (j) CH N , MeOH/Et O, ∼94%.
2
2
2
both the H and 13C NMR spectra of the sodium carboxylate
erythro-35 were much simpler than the corresponding spectra
of the erythro-8/9/34 mixture, thus confirming that the original
product mixture was composed only of pairs of equivalent,
diastereomeric tetraoxygenated compounds. The difference in
chemical shifts observed for the resonances of C-1, C-5, C-6,
and C-10 of erythro-35 and (S,S)-35 also confirmed the
diastereomeric relationship of these sodium carboxylates and,
thus, of erythro-8/9 and (S,S)-8/9. The presence of
dihydroxylactones and trihydroxyesters in both the unlabeled
and deuterium-labeled erythro product mixtures was confirmed
1
1
7. Dihydroxylation of (E)-alkenes under standard SAD
conditions usually occurs more quickly than that of the
corresponding (Z)-alkenes. Thus, oxidation of the isomeric
mixture 36 at this stage with 0.15 equiv of AD-mix-α (26 h)
enabled complete dihydroxylation of the (E)-alkene impurity
while leaving the majority of (Z)-36 unreacted. Chromato-
graphic separation of the diol from the unreacted alkene thus
provided geometrically pure (Z)-36. The synthesis of racemic
erythro-8/9 was undertaken because there was some evidence
22
that erythro diols were unlikely to be P450 substrates.
Dihydroxylation of alkene (Z)-36 was thus performed using
by ESI mass spectrometry, but again only the dihydroxylactones
catalytic OsO with N-methylmorpholine N-oxide (NMO) as
4
2
erythro-8 and [ H ]-erythro-8 were observed by GC/MS
the stoichiometric co-oxidant (Upjohn conditions) to provide a
racemic mixture of erythro-37 in 90% yield (Scheme 7).
Reductive cleavage of the benzyl ether of erythro-37 (by
catalytic hydrogenation or with lithium/liquid ammonia) and
then acid-catalyzed methanolysis of the THP moiety to afford
the triol erythro-28 proved to be inefficient. However, acid-
catalyzed THP deprotection of erythro-37 followed by hydro-
genolysis of the benzyl ether of the resulting triol erythro-38
4
analysis. Furthermore, comparison of the MS fragmentation
2
patterns for erythro-8 and [ H ]-erythro-8 indicated that the
4
tetradeuterated compound was the only clearly detectable
2
labeled species present (≤1% [ H ]).
0
Synthesis of Compounds with Dioxygenated Chains.
Several compounds with dioxygenated chains were then
synthesized on the basis of the results of feeding experiments
with the various stereoisomers of deuterium-labeled 8/9 (vide
(
Pd/C, MeOH) proceeded cleanly to afford the desired tetraol
2
2
infra). The dihydroxyesters [ H ]-10 (28% yield) and [ H ]-11
4
4
erythro-29 in near-quantitative yield. Having obtained the
tetraol erythro-29, synthesis of the unlabeled and deuterium-
(
19%) were obtained in a 3:2 ratio from the standard
2
hydroboration−oxidation of unsaturated hydroxyester [ H ]-
(E)-27. Surprisingly, the 5,10-dihydroxyester [ H ]-11 did not
4
labeled dihydroxylactone/trihydroxyester mixtures, erythro-8/9
2
2
4
(
Scheme 7) and [ H ]-erythro-8/9 (Figure 3, cf. Scheme 6),
4
cyclize to form a 10-hydroxylactone (cf. compounds 8 and 12),
proceeded in a manner analogous to that described for the
which led to difficulties in its chromatographic separation from
corresponding threo compounds above.
2
As observed for the threo analogues, the 1H and 13C NMR
[ H
4
]-10. Two ∼9:1 isomerically enriched mixtures (10:11 and
11:10) were thus obtained, and this level of enrichment was
spectra of both the final unlabeled and deuterium-labeled
2
2
believed to be sufficient to allow differentiation between [ H
]-
4
erythro product mixtures (erythro-8/9/34 and [ H ]-erythro-8/
4
2
1
0 and [ H ]-11 (Figure 4) in terms of deuterium
4
9/34) were complicated. A small amount of the unlabeled
incorporation into spiroacetal 1 in feeding experiments. While
erythro product mixture was treated with NaOD in D O, and
2
the position of the newly introduced hydroxyl group (C-6 in
2
2
[
H ]-10 and C-5 in [ H ]-11) could not be determined from
4
4
2
Figure 3. Deuterium-labeled trihydroxyester [ H ]-erythro-9 and
Figure 4. Deuterium-labeled methyl 6,10-dihydroxytetradecanoate
4
2
2
2
dihydroxylactone [ H ]-erythro-8.
[ H ]-10 and methyl 5,10-dihydroxytetradecanoate [ H ]-11.
4
4
4
E
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
2
their NMR spectra, the mass spectra of these compounds
unsaturated ester [ H ]-(E)-47 in good yield. Sharpless’
2
2
(available from GC/MS) were clearly distinguishable and were
asymmetric dihydroxylation of [ H ]-(E)-47 under standard
conditions then provided the desired hydroxylactones [ H
(S,S)-12 (9% yield; from AD-mix-α) and [ H ]-(R,R)-12 (10%
yield; from AD-mix-β). Similar difficulties in yield and stability
were experienced with [ H
threo-8 (Scheme 3) but overall [ H ]-threo-12 appeared to be
slightly more stable and were available in usable quantities for
feeding experiments from this synthesis.
2
2
thus used to assign their structures. Key mass fragments used to
]-
2
2
2
distinguish these compounds include m/z 113 for [ H ]-10 and
2
4
2
m/z 99 for [ H ]-11 (thought to arise from lactonization and
4
2
2
accompanied loss of methanol, with subsequent scission of the
2
]-threo-12 as initially with [ H
]-
4
2
2
alkyl chain from the lactone ring), and m/z 145 for [ H ]-10
2
4
(
from scission of the bond between C-6 and C-7, adjacent to
the newly introduced hydroxyl group).
Synthesis of Monooxygenated Esters. Several mono-
oxygenated esters were also synthesized, based on the results of
feeding experiments with the various dioxygenated chain
compounds (vide infra). The key intermediate in the synthesis
2
2
Scheme 8. Synthesis of [ H ]-(S,S)-12 and [ H ]-(R,R)-12
2
2
a
from Hexanal and Alkyne 18
2
2
of [ H ]-13 and [ H ]-14 (oxygenated at C-10) was 10-
4
4
oxotetradecanoic acid (48), which was available in near-
quantitative yield in three steps from alkyne 17 via a series of
standard transformations (Scheme 9). Similarly, 6-oxotetrade-
2
2
Scheme 9. Synthesis of [ H ]-13 and [ H ]-14 from
Compound 17
4
4
a
a
Reagents and conditions: (a) H , 10% Pd/C, MeOH; (b) p-TsOH,
2
MeOH, 98% over two steps; (c) Jones’ reagent, acetone, 0 °C to rt,
9
7%; (d) LiOD, D O/THF; (e) CH N , MeOH/Et O, 0 °C to rt,
2 2 2 2
2
a
Reagents and conditions: (a) stabilized ylide 39, CH Cl , reflux, 92%,
2
2
95% over two steps, ≤1% [ H ]; (f) NaBH , MeOH, 0 °C to rt, 94%,
≤1% [ H ].
0
4
2
2
≥
95% E isomer; (b) H , 5% Pd/C, EtOH, quantitative, ∼20% [ H ];
2
2
0
0
(
c) LiAlH , Et O, 0 °C to rt, 99%; (d) I , PPh , imidazole, CH CN/
4 2 2 3 3
2
Et O (1:3), 0 °C to rt, 66%, ∼20% [ H ]; (e) (i) n-BuLi, THF, −40
2
0
2
2
°
C, (ii) HMPA, iodide [ H ]-43, −40 °C to rt, 70%, ∼20% [ H ]; (f)
2
0
2
Li (s)/NH (l), t-BuOH/THF (3:5), −78 °C, 79%, ∼20% [ H ]; (g)
3
0
canoic acid (49) was the key intermediate in the initial
synthesis of [ H ]-15 and [ H ]-16 (oxygenated at C-6) and
was obtained from THP-protected 6-hydroxyhexanal (50)
and commercially available 1-bromooctane in three steps
(Scheme 10). Ketoacids [ H ]-48 and [ H ]-49 were produced
4 4
by base-catalyzed deuterium exchange (≤1% [ H ]) and
esterified to afford the ketoesters [ H ]-13 and [5,5,7,7- H ]-
2
p-TsOH, MeOH, quantitative, ∼20% [ H ]; (h) Jones’ reagent,
2
2
0
4
4
acetone, 0 °C to rt; (i) CH N , MeOH/Et O, 0 °C to rt, 44% over two
24
2
2
2
2
2
steps, ∼20% [ H ]; (j) [ H ]-(S,S)-12: AD-mix-α, MeSO NH , t-
0
2
2
2
2
2
BuOH/H O (1:1), 0−4 °C, 9%, ∼20% [ H ]; [ H ]-(R,R)-12: AD-
2
0
2
2
2
2
mix-β, MeSO NH , t-BuOH/H O (1:1), 0−4 °C, 10%, ∼20% [ H ].
2
2
2
0
2
0
2
2
4
4
The synthesis of the enantiomeric, deuterium-labeled 6-
2
2
2
2
hydroxylactones [ H ]-(S,S)-12 and [ H ]-(R,R)-12 (Scheme
Scheme 10. Synthesis of [5,5,7,7- H ]-15 and [5,5,7,7- H ]-
4 4
a
2
2
8
), with threo vicinal diols, commenced with Wittig addition of
16 from Aldehyde 50
the stabilized ylide ethyl 2-(triphenylphosphoranylidene)-
2
3
acetate (39) to hexanal. This afforded ethyl 2-octenoate
(E)-40] in 92% yield as a 19:1 mixture of E and Z isomers,
with the coupling constant for H-3 (δ 6.94 ppm) and H-2
[
H
(
(
5.79 ppm) revealing the E stereochemistry of the major isomer
J = 15.7 Hz). Catalytic reduction of (E)-40 with deuterium
3
gas over Pd/C gave a mixture of labeled compounds (due to
3
,4
2
H−D exchange during the reaction) with [ H ]-41 as the
2
2
predominant deuterated product (∼20% [ H ]), and subse-
quent LiAlH -mediated ester reduction yielded [ H ]-42. The
alcohol [ H ]-42 was converted to the iodide [ H ]-43 (66%
0
2
4
2
2
2
2
2
yield), which was subsequently reacted with the anion of
a
Reagents and conditions: (a) 1-octylmagnesium bromide, Et O, 0 °C,
7
2
2
protected 5-hexyn-1-ol 18 to provide the target alkyne [ H ]-
2
70%; (b) p-TsOH, MeOH, 96%; (c) Jones’ reagent, acetone, 0 °C to
rt, 96%; (d) LiOD, D O/THF; (e) CH N , Et O, 0 °C to rt, 63% over
4
4 in 70% yield. Lithium/liquid ammonia-mediated reduction
2
2
2
2
2
2
and acid-catalyzed deprotection to [ H ]-46, and Jones’
two steps, ≤1% [ H ]; (f) NaBH , MeOH, 0 °C to rt, 88%, ≤1%
2
0
4
2
oxidation and subsequent esterification afforded the δ,ε-(E)-
[ H ].
0
F
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
5, respectively; ketone reduction gave the desired hydrox-
Featured Article
1
diet. Analysis of the volatile emissions of the flies was
conducted by solid-phase microextraction (SPME) and GC/
MS without disruption of either the flies or the incorporation
experiments, as described previously. SPME sampling was
carried out once a day following administration of the
deuterated substrates for up to 5 days (the average duration
of an experiment was 2−3 days). An average of three separate
experiments were conducted for each substrate. In all
experiments, spiroacetal 1 was the only compound observed
during SPME-GC/MS analysis. As previously summarized by
2
2
yesters [ H ]-14 and [5,5,7,7- H ]-16.
4
4
2
2
Both [5,5,7,7- H ]-15 and [5,5,7,7- H ]-16 have deuterium
4
4
34
at one of the sites of potential in vivo hydroxylation (C-5); this
could hinder their incorporation into spiroacetal 1 as P450-
mediated hydroxylation is known to exhibit significant primary
25
kinetic isotope effects. Thus, the synthesis of isotopomers
2
2
[
7,7,8,8- H ]-15 and [7,7,8,8- H ]-16, which are labeled solely
4
4
at sites not expected to undergo hydroxylation, was undertaken.
Instead of base-catalyzed exchange, this synthetic route
1
(
Scheme 11) employed catalytic reduction of alkyne 54 with
Booth et al., spiroacetals undergo characteristic mass
spectrometric fragmentations. This greatly facilitates the
detection of specific in vivo deuterium incorporation into
spiroacetals, as different mass fragment ions are produced by
spiroacetals containing different numbers of deuterium atoms
and by isotopomers with different sites of labeling (Figure 5).
2
2
Scheme 11. Synthesis of [7,7,8,8- H ]-15 and [7,7,8,8- H ]-
1
4
4
a
6 from 1-Octyne and Aldehyde 50
a
Reagents and conditions: (a) (i) n-BuLi, THF, −40 °C, (ii) aldehyde
5
0, −40 °C to rt; (b) DHP, p-TsOH, CH Cl , 0 °C to rt, 74% over
2
2
2
two steps; (c) H , Wilkinson’s catalyst, benzene; (d) p-TsOH,
2
2
MeOH, 80% over two steps, ≤1% [ H ]; (e) PDC, DMF; (f) CH N ,
0
2
2
2
MeOH/Et O, 0 °C to rt, 71% over two steps, ≤1% [ H ]; (g) NaBH ,
2
0
4
2
MeOH/Et O, 0 °C to rt, 87%, ≤1% [ H ].
2
0
deuterium gas over Wilkinson’s catalyst for the regiospecific
introduction of deuterium atoms at C-7 and C-8. Obtained in
24
two steps from aldehyde 50 and commercially available 1-
octyne, alkyne 54, with both hydroxyl groups protected, was
chosen as the substrate for deuteration because catalytic
reduction of alkyne moieties adjacent to hydroxyl or ketone
groups has been reported to co-occur with varying degrees of
26−29
isomerization and hydrogenolysis.
Furthermore, compar-
ison of the catalytic reduction of alkynols and their THP-
derivatives has indicated that deuteration over Wilkinson’s
3
0−32
catalyst
proceeds to a greater extent and with greater
regiospecificity when no exchangeable hydrogen atoms are
32
present in the substrate. Following the reduction of 54 using
deuterium gas, standard THP-deprotection cleanly provided
2
regiospecifically labeled [7,7,8,8- H ]-1,6-tetradecanediol
4
2
(
[ H ]-53), which was further elaborated to afford the desired
ketoester [7,7,8,8- H ]-15 and hydroxyester [7,7,8,8- H ]-16
≤1% [ H ]). The use of a homogeneous catalytic system
ensured the specific incorporation of four deuterium atoms at
4
Figure 5. Example of feeding experiment results from SPME-GC/MS
2
2
4
4
analysis. Selected GC/MS SIM traces for feeding experiments with (a)
2
(
2
0
sucrose (control) and (b) [ H ]-(S,S)-8/9, 46 h following dietary
4
+•
administration (solid gray line: m/z 156, M for 1; dotted black line:
+•
2
only positions C-7 and C-8, and the isotopomeric relationship
m/z 160, M for [ H ]-1). Mass spectra of spiroacetals (c) 1 and (d)
4
2
2
2
2
of [7,7,8,8- H ]-15 and [7,7,8,8- H ]-16 with [5,5,7,7- H ]-15
[5,5,11,11- H ]-1 formed by specific in vivo deuterium incorporation
]-(S,S)-8/9. (e) Selected characteristic fragmentation
patterns for 1 and [5,5,11,11- H ]-1. Labels A and B in (c) and (d)
4
4
4
4
2
2
and [5,5,7,7- H ]-16 was confirmed by NMR. No H−D
scrambling or overincorporation of deuterium was detectable
by NMR and GC/MS analysis, as is common when
from [ H
4
4
2
4
correspond to the fragments depicted in (e).
3
,4
heterogeneous Pd/C catalysts are used and was observed
2
for [ H ]-41.
In addition to monitoring the total ion current (TIC) of the
GC/MS, selected ion monitoring (SIM) was also used to
improve the sensitivity of the analyses. Several factors can
influence deuterium incorporation observed in experiments
using live insects; these relate to the health and age of the
insects, the deuteration-levels of substrates, the method of
analysis, and external conditions such as temperature and light
2
Administration of Potential Spiroacetal Precursors to
Flies and Deuterium Incorporation Analysis. No
permission from national or local authorities was required to
perform in vivo studies with fruit flies. The deuterium-labeled
compounds were administered to sexually mature male B.
33
cacuminata (at least 10 days postemergence) through their
G
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
exposure. Qualitative comparisons of deuterium incorporation
are thus more meaningful than quantitative determinations.
Analysis of GC/MS data allows qualitative estimates to be
made, based upon which administered substrates are
from the experiments with single substrates suggested that the
threo diols were the preferred substrates for oxidative C−C
bond cleavage rather than erythro diols. Thus, the threo diols
were expected to inhibit the incorporation of the erythro diols
and the erythro diols were not expected to affect threo
processing. The results of these mixed substrate experiments
may reflect factors such as greater bioavailability of the erythro
isomers in vivo or greater susceptibility of the threo compounds
to processing by other enzymes. In addition to being processed
at a low level by biosynthetic enzyme(s), it is possible that the
erythro diols have an inhibitory effect on them and thus
decrease threo diol incorporation into 1.
7
categorized into qualitative incorporation levels: in this case,
“some incorporation”, “low incorporation”, and “no detectable
incorporation” (Supporting Information).
Dihydroxylactones/Trihydroxyesters. As diastereoselec-
tivity between similar threo and erythro diol substrates has been
observed previously in P450-mediated oxidative C−C bond
22
cleavage reactions in vitro, it was initially hypothesized that
2
[
H ]-erythro-8/9 may not be incorporated into spiroacetal 1 in
4
2
vivo to as great an extent as the threo isomers, [ H ]-(S,S)-8/9
or [ H ]-(R,R)-8/9. However, it was unclear whether any
Nevertheless, the diastereoselectivity observed in this
biosynthetic C−C bond cleavage reaction, with the threo
4
2
4
2
2
selectivity between the threo isomers would be observed, as
deuterium-labeled substrates [ H ]-(S,S)-8/9 and [ H ]-(R,R)-
4
4
only low enantioselectivity in vitro has been observed for such a
8/9 both being specifically processed into spiroacetal 1 at a
22
2
reaction previously. The specific incorporation of deuterium
higher level than [ H ]-erythro-8/9, strongly supports the
4
2
from the various stereoisomers of [ H ]-8/9 would result in the
hypothesis that this step is enzyme-mediated rather than an
adventitious chemical process. This finding, and the lack of
preference for either the (S,S) or (R,R) substrate, are
reminiscent of the high degree of diastereoselectivity but low
level of enantioselectivity between threo substrates observed in
4
2
formation of labeled spiroacetal [5,5,11,11- H ]-1; thus, SIM
4
monitoring of mass fragment ions identified for 1 and
2
[
5,5,11,11- H ]-1 was used to aid the detection of deuterium
4
incorporation. Not unexpectedly, both the threo compound
2
2
22
mixtures, [ H ]-(S,S)-8/9 and [ H ]-(R,R)-8/9 were found to
the C−C bond cleavage reaction mediated by P450BioI. This
4
4
be incorporated into spiroacetal 1 in vivo (“some incorpo-
ration”) in several independent experiments, supporting the
inclusion of an oxidative C−C bond cleavage step in the
biosynthetic pathway. Incorporation was monitored by
comparison of the magnitudes of the molecular ion currents
was thought to arise because, although dihydroxy-fatty acids
themselves are cleaved by P450BioI, acyl carrier protein-bound
fatty acids are now known to be the true enzyme substrates;
this may also be the situation for the enzyme(s) involved in the
biosynthesis of spiroacetal 1. While it is clear that both the threo
vicinal diols are processed to 1 in B. cacuminata more efficiently
than the erythro diols, this is not necessarily indicative of the
natural substrate stereochemistry as both threo isomers may be
enzyme substrates but only one may occur naturally.
MIC) for m/z 156 (M+ of natural 1) and m/z 160 (M of
•
+•
(
2
[
H ]-1) in GC/MS chromatograms. However, no consistent,
4
appreciable difference in selectivity between the threo isomers
2
2
(
[ H ]-(S,S)-8/9 and [ H ]-(R,R)-8/9) was detected across
4
4
several experiments by SIM. Comparison of the SIM traces for
Compounds with Dioxygenated, Monooxygenated,
and Unsubstituted Chains. Feeding experiments were next
carried out with deuterium-labeled, racemic dihydroxyesters
mass ions that would result from the fragmentation of
2
[
(
5,5,11,11- H ]-1 against those due to the fragmentation of 1
4
2
2
2
2
Figure 5) indicated that [5,5,11,11- H ]-1 was formed by the
[ H ]-10 and [ H ]-11 and hydroxylactones [ H ]-(S,S)-12 and
4
4
4
2
2
specific incorporation of the administered substrates, and was
observed to increase over the duration of the experiments.
Administration of substrate mixtures containing ∼50%
[ H ]-(R,R)-12, all potential precursors of 8/9. The greatest
2
degree of deuterium incorporation into spiroacetal 1 was
2
observed from the 6,10-dihydroxyester [ H ]-10 (“some
4
deuterated substrate with 50% unlabeled substrate of the
incorporation”), while a much lower level of incorporation
2
2
opposite stereochemistry (i.e., [ H ]-(S,S)-8/9 with (R,R)-8/9
was observed from the 5,10-dihydroxyester [ H ]-11, and none
4
4
2
2
and (S,S)-8/9 with [ H ]-(R,R)-8/9) was then conducted in
from either of the 5,6-dioxygenated hydroxylactones [ H ]-
4
2
2
order to investigate further any selectivity of incorporation
between the threo isomers. These experiments also indicated no
appreciable enantioselectivity. In contrast to the threo isomers, a
(S,S)-12 or [ H ]-(R,R)-12. Specifically labeled spiroacetal
2
2
[5,5,11,11- H ]-1 was detected following administration of
4
2
[ H ]-10, thus indicating that ω-4 hydroxylation of a fatty acid
4
very low level of deuterium incorporation was observed from
equivalent occurs prior to vicinal diol formation and that ω-9
hydroxylation occurs as the final step prior to oxidative C−C
bond cleavage.
2
[
H ]-erythro-8/9 (“low incorporation”). This incorporation
4
was not evident by examination of the mass spectrum of
emitted spiroacetal 1 and required careful inspection of GC/
MS SIM traces to be detected. The coadministration of the β-
oxidation inhibitor 2-fluorostearic acid was not found to visibly
increase deuterium incorporation from any of the threo or
erythro substrates.
Feeding experiments were next carried out with a series of
monooxygenated esters to investigate the order in which ω-4
and ω-8 oxidation occurs. No detectable deuterium incorpo-
ration into 1 was observed from either the 6-ketoester
2
2
[5,5,7,7- H ]-15 or the 6-hydroxyester [5,5,7,7- H ]-16, even
4
4
Interestingly, deuterium incorporation into 1 was observed
following the coadministration of the β-oxidation inhibitor 2-
fluorostearic acid. This lack of observable incorporation into 1
does not exclude such compounds as natural biosynthetic
precursors in vivo and is likely to be due to their extensive
diversion into other metabolic pathways because of their strong
following the administration of mixed substrates consisting of
2
∼
(
50% [ H ]-erythro-8/9 and 50% unlabeled (S,S)-8/9 or
4
2
R,R)-8/9, which was comparable to that observed from [ H ]-
4
erythro-8/9 alone. Furthermore, lower levels of deuterium
incorporation than those resulting from the administration of
resemblance to endogenous fatty acids. Indeed, the incorpo-
2
2
2
either [ H ]-(S,S)-8/9 or [ H ]-(R,R)-8/9 alone were observed
ration of [ H ]-10 into 1 was observed to increase following the
4
4
4
following the administration of mixtures of unlabeled erythro-8/
coadministration of 2-fluorostearic acid, thus supporting the
hypothesis that fatty acid like potential precursors are naturally
degraded via the β-oxidation pathway in vivo. We also
2
2
9
with either [ H ]-(S,S)-8/9 or [ H ]-(R,R)-8/9. The results
4 4
of these experiments were surprising, as the incorporation levels
H
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
hypothesized that the lack of observed deuterium incorporation
spiroacetal biosynthetic enzyme(s) than those with C14 chains
(cf. compounds 8−16). Although fatty acid metabolizing P450s
often have preferred substrate chain lengths, the chain-length
specificity of the spiroacetal biosynthetic enzymes of B.
cacuminata (or B. oleae) has not yet been investigated.
The relative levels of in vivo deuterium incorporation into
spiroacetal 1 observed from the various administered fatty
ester-type compounds are shown in Table 1. These in vivo
2
2
into 1 from [5,5,7,7- H ]-15 and [5,5,7,7- H ]-16 may have
4
4
arisen because of the presence of deuterium atoms at C-5, a site
of further hydroxylation, as P450-mediated oxygen insertion
25
exhibits a significant primary isotope effect. Administration of
2
2
the isotopomers [7,7,8,8- H ]-15 and [7,7,8,8- H ]-16 was then
4
4
carried out but deuterium incorporation from these compounds
was again not observed and the coadministration of 2-
fluorostearic acid did not change these results. This suggested
that ω−4 oxidation is likely to precede ω−8 oxidation. In order
to test this hypothesis, the administration of 10-ketoester
Table 1. Incorporation Levels of Deuterium-Labeled
2
Precursors into Spiroacetal [ H ]-1
x
2
2
[
H ]-13 and 10-hydroxyester [ H ]-14 was conducted.
4
4
oxygenation of fatty
ester chain
some
low
no detectable
incorporation
Deuterium incorporation was not observed from the
incorporation incorporation
2
hydroxyester [ H ]-14, with or without coadministration of 2-
4
2
2
trioxygenated
[ H ]-(R,R)- [ H ]-
4
/9
4
fluorostearic acid. A very low level of deuterium incorporation
8
erythro-8/9
2
was, however, observed from ketoester [ H ]-13 upon careful
2
4
[ H ]-(S,S)-
4
examination and comparison of SIM traces for fragment ions of
8/9
2
[2H
[2H
[2H
2
[
5,5,11,11- H ]-1 and 1. This observation tentatively suggests
dioxygenated
]-10
4
4
]-11
]-13
[ H
2
2
4
]-(R,R)-12
]-(S,S)-12
4
2
that ω−4 oxidation occurs prior to ω−8 oxidation.
[ H
monooxygenated
[2H
]-14
Deuterium incorporation from monooxygenated and un-
substituted esters has not previously been observed in B.
cacuminata across several independent experiments, despite the
coadministration of β-oxidation inhibitors. This is likely to be
because of their diversion into other metabolic pathways, which
4
2
[5,5,7,7- H
]-15
4
2
[
[
[
5,5,7,7- H ]-16
4
2
7,7,8,8- H ]-15
4
2
7,7,8,8- H ]-16
4
2
unsubstituted
[ H ]-55
also explains why a very low level of deuterium incorporation
4
2
was observed from [ H ]-13 (and thus, somewhat surprisingly,
4
2
none from hydroxyester [ H ]-14). Such a result has in fact
4
investigations have established that an oxidative process
culminating in a C−C bond cleavage step is integral to the
generation of the nine-carbon dioxygenated unit that forms
spiroacetal 1 in male B. cacuminata. The results are consistent
with this being an enzyme-mediated process and indicate that it
been observed previously during in vivo investigations of
spiroacetal pheromone biosynthesis in B. tryoni, in which
deuterium-labeled ketones were incorporated into spiroacetals
efficiently while their corresponding alcohols were not
4
detectably incorporated. Deuterium-labeled methyl hexadeca-
occurs stereoselectively in nature. The in vivo transformation of
2
2
noate [ H ]-55 (Figure 6), available to us from other work, was
dihydroxylactones/trihydroxyesters [ H ]-8/9, trihydroxy-fatty
4
4
then administered to flies. Surprisingly, a low level of
acid equivalents containing stereochemically defined vicinal diol
moieties, into spiroacetal 1 was observed to occur with clear
threo diastereoselectivity, although no preference in incorpo-
2
incorporation was observed from [ H ]-55, which was
4
2
comparable to that observed from [ H ]-erythro-8/9 and
4
2
greater than that observed from ketoester [ H ]-13. The
ration was observed for either the (R,R) or (S,S) enantiomers.
4
2
2
presence of labeled spiroacetal [3,3,4,4- H ]-1 could only be
Incorporation of dihydroxyester [ H ]-10 strongly suggested
4
4
detected by careful examination of SIM traces.
that the trioxygenated biosynthetic intermediate represented by
8
/9 is formed by ω-9 oxidation of its dioxygenated precursor,
and investigations into the earlier biosynthetic steps using keto-
and hydroxyesters have tentatively indicated that the
dioxygenated precursor itself is formed by ω-4 oxidation of a
fatty acid equivalent, followed by ω-8 oxidation of the
monooxygenated species.
2
Figure 6. Deuterium-labeled methyl hexadecanoate [ H ]-55.
4
The spiroacetal biosynthetic pathway in B. cacuminata (and
presumably B. oleae) is now proposed to commence with the
ω-4 oxidation of a fatty acid equivalent, followed by ω-8
oxidation to afford a dioxygenated precursor (Scheme 12).
Subsequent ω-9 oxidation affords a trioxygenated fatty acid
equivalent with a threo diol moiety that appears to undergo
enzyme-mediated oxidative C−C bond cleavage to afford 5-
hydroxynonanal (4). Elaboration of 4 to the spiroacetal 1 and
hydroxyspiroacetal derivatives then occurs by a series of well
2
Despite the ketoester [ H ]-13 being a more advanced
4
2
2
precursor for spiroacetal [ H ]-1 than the ester [ H ]-55, the
lower level of deuterium incorporation observed from [ H ]-13
may reflect greater metabolic susceptibility or its greater toxicity
compared to [ H ]-55. Several experiments demonstrated that
flies administered ketoester substrates died much sooner than
those administered hydroxyesters or other compounds, even
when sugar loadings of less than 2% w/w were used.
4
4
2
4
2
4
8
established steps (Scheme 2).
Nevertheless, the very low level of incorporation observed
Oxidative C−C bond cleavage is one of the most impressive
yet relatively uncommon transformations that P450s catalyze.
Often occurring as the final step in sequential substrate
oxidations, oxidative C−C bond scission can occur adjacent to
hydroxyl groups, carbonyl groups, and amines. The majority of
well-known and characterized examples are found in eukaryotic
steroid biosynthesis, with a small number having roles in
biodegradation and a sole example known from a prokaryotic
2
from [ H ]-13 and the lack of observable incorporation from
4
2
2
[
H ]-15 and [ H ]-16 suggests that the biosynthesis of
4 4
spiroacetal 1 in B. cacuminata commences with ω-4 oxidation
of a fatty acid equivalent. The surprising level of deuterium
2
incorporation from labeled methyl hexadecanoate [ H ]-55
4
could also be an indication that fatty acid equivalents with C16
(or longer) chains may be better substrates for the responsible
I
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
Scheme 12. Proposed Biosynthesis of Spiroacetal 1 and Hydroxyspiroacetal Derivatives in B. cacuminata from a Fatty Acid
Equivalent, Showing the Origin of the Oxygen Atoms
2
2
biosynthetic pathway. Only two examples of oxidative diol
the appropriate prefix, [ H ] or [ H ], but without position descriptors
4 2
22,35,36
except when reference is made to different isotopomers, in which case
the position(s) of deuterium labeling are specified. However,
nomenclature for selective labeling has been used throughout the
Experimental Section as only the complete mixture of products can
account for the spectroscopic data observed.
cleavage are currently well characterized
and these
reactions are reported to occur stereoselectively. It is possible
that the actual species that undergoes C−C bond cleavage in
vivo is not the diol but is rather a hydroxyketone (cf. reactions
mediated by mammalian CYP17 during steroid biosyn-
4
6
Synthesis of Key Intermediate 17 from 1-Octen-4-ol (20).
3
7−39
14
thesis
tion
and by P450s involved in olanexidine biodegrada-
) or a dione (cf. the anaerobic cleavage of cyclo-
((Oct-1-en-4-yloxy)methyl)benzene (21). 1-Octen-4-ol (20) (8.87
g, 69.2 mmol) was added dropwise to a suspension of NaH (60%
dispersion in mineral oil, 5.08 g, 127.0 mmol) in anhydrous THF (60
4
0−42
hexane-1,2-dione to form 6-oxohexanoate that is mediated by
the thiamine pyrophosphate-dependent enzyme cyclohexane-
mL) with stirring at 0 °C under a N atmosphere. The mixture was
allowed to warm to room temperature and stirred for 1 h. BnBr (98%,
.0 mL, 74.2 mmol) was added dropwise, followed by tetra-n-
butylammonium iodide (250 mg, cat.). The reaction mixture was
stirred at room temperature for 92 h and then was recooled to 0 °C.
Aqueous HCl solution (5 M, 50 mL) was added cautiously to quench
the reaction, and the mixture was extracted with petroleum spirits 40−
0 (6 × 40 mL). The combined organic extract was washed with
saturated aqueous NaHCO solution (40 mL) and brine (40 mL),
dried over anhydrous MgSO
product was purified by flash column chromatography (silica gel, 100%
petroleum spirits 40−60 to 2% Et O in petroleum spirits 40−60) to
afford 21 (12.73 g, 58.3 mmol, 84%) as a colorless oil. H NMR (400
MHz, CDCl ): δ 0.88 (t, 3H, J = 7.1 Hz, CH -8), 1.22−1.60 (m, 6H,
CH -7, CH -6 and CH -5), 2.31 (m, 2H, CH -3), 3.42 (m, 1H, CH-4),
2
43−45
1
,2-dione hydrolase
from the bacterium Azoarcus sp. strain
9
2
2Lin). However, the diastereoselectivity with which the
2
incorporation of dihydroxylactones/trihydroxyesters [ H ]-8/
4
9
into spiroacetal 1 was observed to occur is reminiscent of the
diol cleavage reactions that are mediated by mammalian P450
during steroid biosynthesis
scc
3
5,36
and by the bacterial enzyme
6
22
P450BioI during biotin biosynthesis. Thus, the results obtained
here are consistent with 5-hydroxynonanal (4) being produced
via an enzyme-mediated oxidative diol cleavage reaction. Given
the derivation of both the oxygen atoms in 1 from molecular
oxygen, it is likely that the enzyme(s) involved are cytochromes
P450.
3
, filtered, and concentrated. The crude
4
2
1
3
3
2
2
2
2
4
.48 and 4.55 (AB q, 2H, JAB = 11.6 Hz, ROCH Ph), 5.02−5.11 (m,
2
CONCLUSION
■
2H, CH -1), 5.84 (ddt, 1H, J = 17.2, 10.1, 7.1 Hz, CH-2), 7.22−7.36
ppm (m, 5H, Ar-H). C NMR (100 MHz, CDCl
2
13
Following the efficient synthesis of a series of deuterium-labeled
potential spiroacetal precursors, the in vivo investigations
described here have allowed the order of oxidative events in the
biosynthetic pathway to spiroacetal 1 in B. cacuminata to be
determined. Building upon previous work, this has allowed
essentially) the complete delineation of the biosynthetic
3
): δ 14.1 (C-8), 22.8
(
4
C-7), 27.6 (C-6), 33.5 (C-5), 38.3 (C-3), 70.9 (ROCH Ph), 78.6 (C-
), 116.8 (C-1), 127.4 (Ar CH), 127.7 (2 × Ar CH), 128.3 (2 × Ar
2
CH), 135.1 (C-2), 139.0 ppm (Ar C). GC/MS (EI) m/z: 218 (0.03,
+
•
+•
8
M ), 177 (2), 161 (2), 107 (1), 92 (9), 91 (100, C
11), 57 (1), 51 (3), 43 (1), 41 (13). HRMS (EI) m/z: M calcd for
C H O 218.1671, found 218.1601. Anal. Calcd for C H O: C,
7 7
H ), 77 (2), 65
+•
(
(
15
22
15 22
pathway from a fatty acid equivalent to 1 and its
hydroxyspiroacetal derivatives (Scheme 12). In addition, it
has justified the inclusion of an enzyme-mediated, multistep,
oxidative C−C bond cleavage process as a key step. This is the
first time such an oxidative transformation has been reported in
insects. Future work will involve demonstrating that this
pathway is also followed by the more pestiferous B. oleae,
identifying the actual P450s involved in the biosynthesis, and
defining their catalytic roles and substrate specificity.
8
2.52; H, 10.16. Found: C, 82.48; H, 10.17.
4
-(Benzyloxy)octan-1-ol (22). Borane−dimethyl sulfide complex
(2.80 mL, 29.5 mmol) was added dropwise to a solution of alkene 21
(4.39 g, 20.1 mmol) in anhydrous CH Cl (50 mL) with stirring at 0
2
2
°C under a N
room temperature, stirred for 2.5 h, and then recooled to 0 °C. EtOH
15 mL) was added dropwise, the mixture was stirred for a further 30
atmosphere. The solution was allowed to warm to
2
(
min, and then aqueous NaOH solution (20%, 25.0 mL, 125.0 mmol)
was added dropwise, followed by H O (30%, 25.0 mL, 220.5 mmol).
2
2
The reaction mixture was allowed to warm to room temperature and
stirred for a further 66 h. The layers were separated, and the aqueous
layer was extracted with CH Cl (6 × 20 mL). The combined organic
extract was washed with brine (20 mL), dried over anhydrous MgSO4,
filtered, and concentrated in vacuo. The crude product was purified by
flash column chromatography (silica gel, 5% EtOAc in petroleum
spirits 40−60 to 100% EtOAc) to afford alcohol 22 (4.13 g, 17.5
mmol, 87%) as a colorless oil. H NMR (400 MHz, CDCl ): δ 0.89 (t,
3H, J = 7.1 Hz, CH -8), 1.22−1.40 (m, 4H, CH -6 and CH -7), 1.44−
1.73 (m, 6H, CH -2, CH -3 and CH -5), 3.41 (m, 1H, CH-4), 3.62
EXPERIMENTAL SECTION
■
2 2
Deuterium-Labeled Compounds. For mixtures of deuterium-
labeled products obtained using selective labeling methods (base-
catalyzed exchange adjacent to ketones, or catalytic reduction of
multiple bonds using deuterium gas), the predominant products
present were determined from analysis of NMR and MS data, and the
levels of unlabeled products present were determined by comparison
of mass fragment peaks obtained from GC/MS. In experimental
schemes and in the discussion of these compounds, the labeled
mixtures are represented by the predominant labeled products using
1
3
3
2
2
2
2
2
(m, 2H, CH -1), 4.48 and 4.53 (AB q, 2H, J = 11.5 Hz, ROCH Ph),
7.22−7.34 ppm (m, 5H, Ar-H). C NMR (100 MHz, CDCl ): δ 14.0
2
AB
2
13
3
J
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
(
C-8), 22.9 (C-7), 27.6 (C-6), 28.6, 30.3, 33.3 (C-5), 63.1 (C-1), 70.9
The reaction mixture was stirred at −78 °C for 4 h and then was
allowed to warm to room temperature while stirring overnight, during
which time NH evaporated. Saturated aqueous NH Cl solution (20
(ROCH Ph), 78.9 (C-4), 127.5 (Ar CH), 127.8 (2 × Ar CH), 128.4 (2
2
+•
×
Ar CH), 138.8 ppm (Ar C). GC/MS (EI) m/z: 236 (0.2, M ), 218
3
4
+•
(
0.1, M − H O), 177 (0.3), 129 (2), 107 (15), 92 (10), 91 (100,
C H ), 77 (2), 65 (9), 57 (2), 55 (5), 45 (1), 43 (4). HRMS (ESI)
mL) was added to quench the reaction and the mixture was extracted
2
+•
with Et O (6 × 20 mL). The combined organic extract was washed
7
7
2
+•
m/z: [M + Na] calcd for C H NaO 259.1674, found 259.1675.
with brine (20 mL), dried over anhydrous MgSO , filtered and
15
24
2
4
Anal. Calcd for C H O : C, 76.23; H, 10.24. Found: C, 76.54; H,
concentrated in vacuo. The crude product was purified by flash
15
24
2
10.20.
column chromatography (silica gel, 9% to 17% Et
2
O in petroleum
1
-((1-Iodooctan-4-yloxy)methyl)benzene (19). I (99%, 2.46 g, 9.6
spirits 40−60) to afford (E)-23 (2.85 g, 9.1 mmol, 93%) as a pale
2
1
mmol) was added portionwise to a solution of alcohol 22 (1.40 g, 5.9
mmol), PPh (99%, 2.56 g, 9.7 mmol), and imidazole (890 mg, 13.1
mmol) in a mixture of anhydrous Et O (12 mL) and CH CN (4 mL)
with stirring at 0 °C under a N atmosphere. The reaction mixture was
yellow oil. H NMR (400 MHz, CDCl
3
): δ 0.88 (t, 3H, J = 7.0 Hz,
-4 and CH -7), 3.36
CH -14), 1.20−1.87 (m, 20H), 1.98 (m, 4H, CH
3
3
2
2
(dt, 1H, J = 9.6, 6.6 Hz, CH-1), 3.47 (m, 1H, CH-6′), 3.56 (m, 1H,
CH-10), 3.70 (dt, 1H, J = 9.6, 6.8 Hz, CH-1), 3.84 (m, 1H, CH-6′),
4.55 (dd, 1H, J = 4.2, 2.7 Hz, CH-2′), 5.38 ppm (m, 2H, CH-5 and
2
3
2
allowed to warm to room temperature, stirred for a further 3 h, and
then recooled to 0 °C. MeOH (5 mL) was added dropwise to quench
the reaction, and the solvent was removed in vacuo. The residue was
purified by flash column chromatography (silica gel, 100% petroleum
spirits 40−60 to 5% EtOAc in petroleum spirits 40−60) to afford
CH-6). 13C NMR (100 MHz, CDCl
): δ 14.1 (C-14), 19.6, 22.7, 25.5,
3
25.6, 26.2, 27.8, 29.2, 30.8, 32.3, 32.5, 36.9, 37.2, 62.3 (C-6′), 67.5 (C-
1), 71.8 (C-10), 98.8 (C-2′), 130.3 (RHCCHR), 130.4 ppm
+•
(RHCCHR). GC/MS (EI) m/z: 312 (0.2, M ), 155 (0.1), 115
1
+•
iodide 19 (2.01 g, 5.8 mmol, 98%) as a colorless oil. H NMR (500
(0.3), 101 (2), 85 (100, THP ), 81 (6), 69 (8), 67 (22), 57 (17), 55
(26), 43 (26), 41 (49). HRMS (ESI) m/z: [M + Na]+ Calcd for
•
MHz, CDCl ): δ 0.89 (t, 3H, J = 7.1 Hz, CH -8), 1.25−1.40 (m, 4H,
3
3
CH -6 and CH -7), 1.42−1.51 (m, 1H, CH-5), 1.53−1.69 (m, 3H,
C
19
H
36NaO
3
335.2562, found 335.2572. Anal. Calcd for C19
73.03; H, 11.61. Found: C, 72.70; H, 11.26.
(E)-5-Tetradecene-1,10-diol [(E)-24]. A solution of (E)-23 (800
mg, 2.56 mmol) and p-TsOH.H O (25 mg, cat.) in MeOH (20 mL)
was stirred at room temperature for 1 h. Saturated aqueous NaHCO
H O : C,
36 3
2
2
CH -3 and CH-5), 1.80−1.99 (m, 2H, CH -2), 3.16 (t, 2H, J = 7.0 Hz,
2
2
CH -1), 3.38 (m, 1H, CH-4), 4.46 and 4.51 (AB q, 2H, J = 11.6 Hz,
2
AB
13
ROCH Ph), 7.24−7.38 ppm (m, 5H, Ar-H). C NMR (125 MHz,
CDCl ): δ 7.5 (C-1), 14.1 (C-8), 22.9 (C-7), 27.5 (C-6), 29.3 (C-2),
2
2
3
3
3
1
3.4 (C-5), 34.6 (C-3), 70.7 (ROCH Ph), 77.8 (C-4), 127.5 (Ar CH),
solution (30 mL) was added to quench the reaction and MeOH was
evaporated in vacuo. The aqueous solution was extracted with EtOAc
(2 × 50 mL) and the combined organic extract was washed with brine
2
27.8 (2 × Ar CH), 128.3 (2 × Ar CH), 138.8 ppm (Ar C). GC/MS
+•
+•
(
(
7
EI) m/z: 289 (2), 255 (0.3, M − C H ), 219 (0.3, M − I), 177
7
7
+•
2), 155 (1), 141 (0.2), 127 (4), 107 (1), 92 (10), 91 (100, C H ),
(50 mL), dried over anhydrous MgSO , filtered and concentrated in
4
7
7
+•
7 (2), 65 (9), 55 (4), 43 (6). HRMS (EI) m/z: M calcd for
vacuo. The crude product was purified by flash column chromatog-
raphy (silica gel, 20% EtOAc in n-hexane) to afford diol (E)-24 (550
mg, 2.41 mmol, 94%) as a colorless solid. 1H NMR (500 MHz,
C H IO 346.0794, found 346.0806.
15
23
2
-(10-(Benzyloxy)tetradec-5-yn-1-yloxy)tetrahydro-2H-pyran
(17). A solution of n-BuLi (1.78 M in hexanes, 6.0 mL, 10.7 mmol)
CDCl
(m, 2H), 1.99 (m, 4H, CH
(t, 2H, J = 6.6 Hz, CH -1), 5.39 ppm (m, 2H, CH-5 and CH-6).
NMR (125 MHz, CDCl ): δ 14.1 (C-14), 22.7, 25.55, 25.60, 27.8,
32.18, 32.22, 32.5, 36.9, 37.2, 62.9 (C-1), 71.9 (C-10), 130.3 (RHC
3
): δ 0.89 (t, 3H, J = 7.1 Hz, CH
3
-14), 1.22−1.50 (m, 14H), 1.55
-7), 3.57 (m, 1H, CH-10), 3.62
2
was added dropwise to a solution of 2-(hex-5-yn-1-yloxy)tetrahydro-
2
-4 and CH
7
13
2H-pyran (18) (2.02 g, 11.1 mmol) in anhydrous THF (10 mL) with
2
C
stirring at −40 °C under a N atmosphere. The solution was stirred at
3
2
−
40 °C for 3 h, then HMPA (99%, 2.5 mL, 14.2 mmol) was added,
followed by the dropwise addition of a solution of iodide 19 (4.86 g,
4.0 mmol) in anhydrous THF (4 mL). The reaction mixture was
+
•
CHR), 130.5 ppm (RHCCHR). GC/MS (EI) m/z: 228 (0.1, M ),
+
•
1
210 (0.3, M − H
O), 186 (1), 171 (1), 149 (0.4), 135 (2), 113 (6),
2
allowed to warm to room temperature and stirred for 20 h. Saturated
aqueous NH Cl solution (20 mL) was added to quench the reaction
98 (7), 93 (11), 82 (17), 79 (23), 67 (36), 57 (26), 55 (38), 41 (100).
HRMS (EI) m/z: M calcd for C14H O : 228.2089, found 228.2093.
28 2
+•
4
and the mixture was extracted with petroleum spirits 40−60 (6 × 20
mL). The combined organic extract was washed with aqueous LiCl
solution (4 M, 6 × 20 mL) and brine (2 × 20 mL), dried over
(E)-10-Oxo-5-tetradecenoic acid [(E)-25]. Jones’ reagent (8 N) was
added dropwise to a solution of diol (E)-24 (300 mg, 1.31 mmol) in
acetone (5 mL) with stirring at 0 °C until the orange color of the
reaction mixture persisted. The reaction mixture was allowed to warm
to room temperature with stirring over 15 min and then was quenched
anhydrous MgSO , filtered and concentrated in vacuo. The crude
4
product was purified by flash column chromatography (silica gel, 2% to
1
8
7% Et O in petroleum spirits 40−60) to afford 17 (3.69 g, 9.2 mmol,
with water (5 mL). The mixture was extracted with Et
and the combined organic extract was washed with brine (2 × 20 mL),
dried over anhydrous MgSO , filtered, and concentrated in vacuo. The
2
O (3 × 20 mL)
2
1
3%) as a colorless oil. H NMR (400 MHz, CDCl ): δ 0.88 (t, 3H, J
3
=
7.1 Hz, CH -14), 1.23−1.87 (m, 20H), 2.16 (m, 4H, CH -4 and
2
4
3
2
CH -7), 3.38 (m, 2H, CH-1 and CH-10), 3.47 (m, 1H, CH-6′), 3.73
crude product was purified by flash column chromatography (silica gel,
10% EtOAc in n-hexane) to afford ketoacid (E)-25 (300 mg, 1.25
(
dt, 1H, J = 9.7, 6.6 Hz, CH-1), 3.84 (m, 1H, CH-6′), 4.48 (s, 2H,
1
ROCH Ph), 4.55 (dd, 1H, J = 4.1, 2.9 Hz, CH-2′), 7.20−7.35 ppm (m,
5
1
6
mmol, 95%, ≥95% E isomer) as a colorless solid. Mp: 36−38 °C. H
2
13
H, Ar-H). C NMR (100 MHz, CDCl ): δ 14.1 (C-14), 18.6, 18.9,
9.6, 22.9, 24.9, 25.5, 26.0, 27.6, 29.0, 30.8, 32.9, 33.5, 62.3 (C-6′),
7.1 (C-1), 70.7 (ROCH Ph), 78.6 (C-10), 80.1 (RC≡CR), 80.2
NMR (500 MHz, CDCl
J = 7.4 Hz, CH -14), 1.27 (sextet, 2H, J = 7.4 Hz), 1.52 (quintet, 2H, J
3
3
): (mixture of E and Z isomers) δ 0.87 (t, 3H,
3
= 7.5 Hz), 1.60 (quintet, 2H, J = 7.4 Hz), 1.67 (quintet, 2H, J = 7.4
Hz), 1.96 (m, 2H), 2.01 (m, 2H), 2.32 (t, 2H, J = 7.5 Hz), 2.36 (2
2
(
×
RC≡CR), 98.8 (C-2′), 127.4 (Ar CH), 127.7 (2 × Ar CH), 128.3 (2
+
•
Ar CH), 139.1 ppm (Ar C). GC/MS (EI) m/z: 400 (0.03, M ), 315
overlapping t, 4H, J = 7.4 Hz and 7.5 Hz), 5.36 ppm (m, 2H, CH-5
+
•
13
(
(
(
(
(
1, M − THP), 309 (0.3), 259 (1), 243 (2), 223 (1), 221 (1), 209
and CH-6). C NMR (125 MHz, CDCl
): (mixture of E and Z
3
isomers) δ 13.8 (C-14), 22.3, 23.5, 23.6 (Z isomer), 24.3, 24.5 (Z
isomer), 25.9, 26.4 (Z isomer), 26.6 (Z isomer), 31.7, 31.9, 33.2, 33.3
2), 195 (1), 191 (2), 181 (1), 177 (1), 169 (1), 157 (1), 151 (5), 143
+
•
1), 135 (3), 129 (1), 107 (5), 101 (2), 92 (9), 91 (100, C H ), 85
95, THP ), 79 (12), 77 (6), 67 (17), 57 (11), 55 (20), 43 (10), 41
17). HRMS (ESI) m/z: [M + Na] calcd for C H NaO 423.2875,
7
7
+
•
(
Z isomer), 41.9, 42.0 (Z isomer), 42.55 (Z isomer), 42.58, 42.7 (Z
+•
isomer), 129.2 (RHCCHR of Z isomer), 129.8 (RHCCHR of E
isomer), 130.1 (RHCCHR of Z isomer), 130.7 (RHCCHR of E
isomer), 179.6 (C-1 of E isomer), 179.8 (C-1 of Z isomer), 211.5 (C-
26
40
3
found 423.2857. Anal. Calcd for C H O : C, 77.95; H, 10.06. Found:
26
40
3
C, 77.78; H, 10.00.
2
1
0 of Z isomer), 211.7 ppm (C-10 of E isomer). GC/MS (EI) m/z: (E
Synthesis of Unsaturated Hydroxyester [ H ]-(E)-27 from
4
+
•
+•
Compound 17. (E)-14-(Tetrahydro-2H-pyran-2-yloxy)tetradec-9-
isomer, as methyl ester) 254 (1, M ), 236 (1), 223 (2, M − OCH ),
3
+
•
en-5-ol [(E)-23]. Lithium metal (350 mg, 50.4 mmol) was added
222 (3, M − MeOH), 212 (3), 194 (2), 180 (2), 165 (4), 154 (9),
portion-wise to liquid NH (100 mL) with stirring at −78 °C until the
147 (6), 137 (10), 123 (21), 122 (15), 95 (31), 94 (61), 85 (86,
3
+•
+•
solution remained blue in color. t-BuOH (9 mL) was added, followed
by a solution of 17 (3.94 g, 9.8 mmol) in anhydrous THF (15 mL).
C H O ), 80 (100), 74 (22), 67 (41), 59 (19, C H O ), 57 (88,
C H ), 55 (58), 43 (40), 41 (94). GC/MS (EI) m/z: (Z isomer, as
5
9
2
3
2
+
•
4
9
K
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
+
•
+•
methyl ester) 254 (1, M ), 246 (1), 223 (2, M − OCH ), 222 (2,
(RCO CH ), 71.4 (C-10), 129.1 (RHCCHR), 131.2 (RHC
3
2
3
+•
+•
M
− MeOH), 212 (2), 194 (1), 180 (2), 165 (6), 154 (11), 147 (9),
37 (11), 123 (22), 122 (17), 95 (31), 94 (66), 85 (85, C H O ), 80
97), 74 (20), 67 (44), 59 (20, C H O ), 57 (100, C H9 ), 55 (62),
3 (44), 41 (100). Anal. Calcd for C H O : C, 69.96: H, 10.07.
CHR), 174.1 ppm (C-1). GC/MS (EI) m/z: 260 (0.2, M ), 242 (1,
+•
+•
1
(
M − H O), 218 (1), 201 (1), 183 (1), 168 (4), 154 (15), 140 (12),
5
9
2
+•
+•
126 (9), 122 (12), 98 (17), 94 (49), 87 (21), 81 (44), 80 (100), 74
(31), 71 (27), 67 (30), 59 (33), 55 (34), 43 (55), 41 (57). HRMS
2
3
2
4
4
14 24 3
+
•
Found: C, 69.86; H, 10.43.
(ESI) m/z: [M + Na] calcd for C H D NaO 283.2187, found
15 24 4 3
2
2
2
Methyl [9- H ,11- H ]-(E)-10-oxo-5-tetradecenoate ([ H ]-
283.2193.
0
;1;2
0;1;2
4
(
E)-26). Lithium metal (∼100 mg, 14.41 mmol) was added cautiously
Synthesis of Unlabeled Threo Dihydroxylactones/Trihydrox-
yesters (S,S)-8/9 and (R,R)-8/9 from (E)-23. (5S,6S)-1-(Tetrahy-
dro-2H-pyran-2-yloxy)tetradecane-5,6,10-triol [(S,S)-28]. Methane-
sulfonamide (97%, 385 mg, 3.93 mmol) and AD-mix-α (Aldrich, 5.166
g) were added to a solution of alkene (E)-23 (924 mg, 2.96 mmol) in
to D O (99.9 atom % D, 15 mL) at 0 °C, and the resulting LiOD
2
solution was added to a solution of ketoacid (E)-25 (270 mg, 1.12
mmol) in anhydrous THF (1 mL). The pale yellow reaction mixture
was stirred at room temperature for 24 h and then cold aqueous HCl
(
0.05 M, 10 mL) was added to acidify the basic reaction mixture. The
a mixture of t-BuOH and H O (1:1, 20 mL) with stirring at 0 °C. The
2
acidic mixture was extracted with cold EtOAc (2 × 50 mL), and the
yellow reaction mixture was stirred at 4 °C for 64 h, and then a
solution of sodium sulfite (∼1 g, 7.93 mmol) in water (10 mL) was
added. The mixture was allowed to warm to room temperature and
combined organic extract was washed with brine (2 × 50 mL), dried
over anhydrous MgSO , filtered, and concentrated in vacuo. The
4
residue was dissolved in MeOH (5 mL) and the solution was cooled to
stirred for 1 h and then was extracted with Et O (6 × 30 mL). The
2
0
°C. Ethereal CH N was added dropwise until the yellow color of
combined organic extract was washed with aqueous NaOH solution
(5%, 30 mL) and brine (30 mL), dried over anhydrous MgSO4,
filtered, and concentrated in vacuo. The crude product was purified by
2
2
the reaction mixture persisted. The yellow solution was stirred at 0 °C
for 15 min and then was allowed to warm to room temperature with
stirring over a further 15 min. Excess CH N was evaporated under a
flash column chromatography (silica gel, 33% Et O in petroleum
2
2
2
stream of N gas and the colorless reaction mixture was concentrated
in vacuo. The residue was purified by flash column chromatography
spirits 40−60 to 100% Et O) to afford triol (S,S)-28 (978 mg, 2.82
2
2
2
4
mmol, 95%) as a waxy, white solid. Mp: 40−46 °C. [α] −18.2 (c
D
1
(
silica gel, 10% EtOAc in n-hexane) to afford a viscous, colorless oil
0.61, MeOH). H NMR (400 MHz, CDCl ): δ 0.88 (t, 3H, J = 6.9 Hz,
3
2
containing [ H ]-(E)-26 (180 mg, 0.70 mmol, 62% over two steps,
CH -14), 1.10−1.87 (m, 24H), 2.52 (br s, 3H, 3 × ROH), 3.39 (m,
4
3
2
≥
95% E isomer, ≤1% [ H ]) as the major deuterium-labeled product.
3H, CH-1, CH-5 and CH-6), 3.47 (m, 1H, CH-6′), 3.57 (m, 1H, CH-
10), 3.73 (m, 1H, CH-1), 3.84 (m, 1H, CH-6′), 4.54 ppm (m, 1H,
0
1
H NMR (500 MHz, CDCl ) (mixture of E and Z isomers): δ 0.86 (t,
3
13
3
1
H, J = 7.4 Hz, CH -14), 1.26 (m, 2H), 1.49 (br t, 2H, J = 7.6 Hz),
.57 (br t, 2H, J = 7.3 Hz), 1.64 (quintet, 2H, J = 7.4 Hz), 1.96 (m,
CH-2′). C NMR (100 MHz, CDCl ): (mixture of diastereomers) δ
3
3
14.1 (C-14), 19.7, 19.8, 21.6, 21.8, 22.3, 22.5, 22.7, 25.4, 27.9, 29.5,
29.6, 30.75, 30.78, 33.2, 33.3, 33.5, 37.0, 37.20, 37.23, 37.3, 62.5 (C-
6′), 62.6 (C-6′), 67.5 (C-1), 71.76 (C-10), 71.80 (C-10), 74.21, 74.23,
74.27, 74.28, 74.30, 74.36, 74.38, 74.40, 99.0 (C-2′), 99.1 ppm (C-2′).
GC/MS (EI) m/z: 245 (0.1), 227 (2), 209 (1), 187 (2), 169 (3), 159
(2), 157 (1), 141 (8), 123 (4), 115 (1), 111 (2), 101 (2), 87 (2), 85
4
H), 2.26 (t, 2H, J = 7.6 Hz, CH -2), 2.28−2.42 (m, 0.2H, residual
2
2
2
hydrogen from CH or CHD at C-9 and/or C-11 of [ H ]-[ H ]-
2
0
3
analogues), 3.62 (s, 3H, RCO CH ), 5.34 ppm (m, 2H, CH-5 and
2
3
CH-6). 13C NMR (125 MHz, CDCl ): δ 13.8 (C-14), 22.3, 23.3, 23.5
3
(
Z isomer), 24.6, 24.8 (Z isomer), 25.8, 26.5 (Z isomer), 31.8, 31.9,
3.3, 33.4 (Z isomer), 40.8−42.2 (m, incl. 41.2 [quintet, JC,D = 19.2
Hz, CD ], 41.8 [quintet, J = 19.0 Hz, CD ], C-9 and C-11), 51.4
+•
3
(100, THP ), 81 (7), 67 (14), 57 (19), 55 (20), 43 (14), 41 (21).
+
•
HRMS (ESI) m/z: [M + Na] calcd for C19
H
38NaO
369.2617, found
H O : C, 65.86; H, 11.05. Found: C,
38 5
2
C,D
2
5
(
RCO CH ), 129.3 (RHCCHR of Z isomer), 129.87 (RHCCHR
369.2626. Anal. Calcd for C19
65.82; H, 11.05.
2
3
of E isomer), 129.92 (RHCCHR of Z isomer), 130.5 (RHCCHR
of E isomer), 174.1 (C-1), 211.7 ppm (C-10). GC/MS (EI) m/z: (E
(5R,6R)-1-(Tetrahydro-2H-pyran-2-yloxy)tetradecane-5,6,10-triol
[(R,R)-28]. Alkene (E)-23 (930 mg, 2.98 mmol) was dihydroxylated
with AD-mix-β (Aldrich, 5.212 g) and methanesulfonamide (97%, 398
+
•
+•
+•
isomer) 258 (1, M ), 240 (1), 227 (3, M − OCH ), 226 (6, M
MeOH), 216 (3), 198 (2), 184 (2), 167 (4), 154 (10), 149 (4), 139
−
3
+•
(
8), 123 (24), 122 (23), 95 (26), 94 (60), 87 (75, C H D O and/or
mg, 4.06 mmol) in a mixture of t-BuOH and H
°C over 64 h, as described for the synthesis of (S,S)-28. Purification by
flash column chromatography (silica gel, 33% Et O in petroleum
spirits 40−60 to 100% Et O) afforded triol (R,R)-28 (983 mg, 2.84
mmol, 95%) as a waxy, white solid. Mp: 40−46 °C. [α]
0.75, MeOH). This compound was spectroscopically identical to
2
O (1:1, 20 mL) at 4
5
7
2
+
•
+•
C H O ), 80 (100), 74 (25), 67 (34), 62 (47), 59 (96, C H D
4
7
2
4
7
2
+•
and/or C H O ), 55 (27), 43 (41), 41 (48). GC/MS (EI) m/z: (Z
isomer) 258 (1, M ), 240 (1), 227 (2, M − OCH ), 226 (6, M
MeOH), 216 (3), 198 (2), 184 (2), 167 (4), 154 (11), 149 (4), 139
2
2
3
2
+
•
+•
+•
−
2
3
2
4
+19.6 (c
D
+•
(
8), 123 (20), 122 (21), 95 (28), 94 (60), 87 (80, C H D O and/or
5 7 2
+
•
+•
+•
C H O ), 80 (93), 74 (23), 67 (31), 62 (47), 59 (100, C H D
(S,S)-28. HRMS (ESI) m/z: [M + Na] calcd for C19H38NaO
5
4
7
2
4
7
2
+
•
and/or C H O ), 55 (31), 43 (41), 41 (48). HRMS (ESI) m/z: [M
+
369.2617, found 369.2611. Anal. Calcd for C19
11.05. Found: C, 65.59; H, 10.97.
H O : C, 65.86; H,
38 5
2
3
2
+
•
Na] calcd for C H D NaO 281.2031, found 281.2022.
15 22 4 3
2
2
Methyl [9- H ,11- H ]-(E)-10-hydroxy-5-tetradecenoate
(5S,6S)-1,5,6,10-Tetradecanetetraol [(S,S)-29]. A solution of (S,S)-
28 (797 mg, 2.30 mmol) and concentrated aqueous HCl (32%, 0.5
mL) in MeOH (10 mL) was stirred at room temperature for 22 h.
0
;1;2
0;1;2
2
(
[ H ]-(E)-27). NaBH (4 mg, 0.11 mmol) was added to a solution
4
4
2
of ketoester [ H ]-(E)-26 (82 mg, 0.32 mmol) in MeOH (5 mL) with
4
stirring at 0 °C. The reaction mixture was allowed to warm to room
temperature and stirred for a further 1 h and then was quenched with
aqueous HCl (0.05 M, 10 mL). The reaction mixture was extracted
with EtOAc (3 × 20 mL), and the combined organic extract was
Solid NaHCO (420 mg) was added to quench the reaction, and the
solvent was evaporated in vacuo. The residue was purified by flash
3
column chromatography (silica gel, 5% to 9% MeOH in CH Cl ) to
2
2
afford (S,S)-29 (580 mg, 2.21 mmol, 96%) as a white solid. Mp: 65−
2
4
1
washed with saturated aqueous NaHCO (2 × 20 mL) and brine (2 ×
67 °C. [α] −20.3 (c 0.62, MeOH). H NMR (400 MHz, CD OD): δ
3
D
3
2
0 mL), dried over anhydrous MgSO , filtered, and concentrated in
0.91 (t, 3H, J = 7.1 Hz, CH -14), 1.22−1.71 (m, 18H), 3.39 (m, 2H,
CH-5 and CH-6), 3.52 (m, 1H, CH-10), 3.55 ppm (t, 2H, J = 6.4 Hz,
4
3
vacuo. The crude product was purified by flash column chromatog-
13
raphy (silica gel impregnated with 10% AgNO , 10% EtOAc in n-
CH -1). C NMR (100 MHz, CD OD): (mixture of diastereomers) δ
3
2
3
2
hexane) to afford a viscous, colorless oil containing [ H ]-(E)-27 (72
14.4 (C-14), 23.21, 23.25, 23.4, 23.8, 29.1, 33.68, 33.71, 33.9, 34.0,
38.1, 38.2, 38.4, 38.5, 62.9 (C-1), 72.3, 72.4, 75.17, 75.23 ppm. HRMS
4
2
mg, 0.28 mmol, 87%, 100% E isomer, ≤1% [ H ]) as the major
0
1
+•
deuterium-labeled product. H NMR (500 MHz, CDCl ): δ 0.89 (t,
(ESI) m/z: [M + Na] calcd for C H NaO 285.2042, found
3
14 30
4
3
H, J = 7.0 Hz, CH -14), 1.22−1.51 (m, 7H), 1.67 (quintet, 2H, J =
285.2039. Anal. Calcd for C H O : C, 64.08; H, 11.52. Found: C,
3
14 30 4
7.4 Hz), 2.00 (m, 4H), 2.29 (t, 2H, J = 7.6 Hz, CH -2), 3.56 (m, 1H,
63.92; H, 11.52.
2
CH-10), 3.65 (s, 3H, RCO CH ), 5.38 ppm (m, 2H, CH-5 and CH-6).
(5R,6R)-1,5,6,10-Tetradecanetetraol [(R,R)-29]. The THP moiety
of (R,R)-28 (768 mg, 2.21 mmol) was cleaved with HCl (32%, 0.5
mL) in MeOH (10 mL) over 22 h, as described for the synthesis of
(S,S)-29. Purification by flash column chromatography (silica gel, 5%
2
3
1
3
C NMR (125 MHz, CDCl ): δ 14.0 (C-14), 22.6, 24.6, 25.2, 27.5,
3
3
1.8, 32.4, 33.3, 35.5−36.8 (m, incl. 35.9 [quintet, JC,D = 18.3 Hz,
CD ], 36.2 [quintet, J
= 18.3 Hz, CD ], C-9 and C-11), 51.4
2
2
C,D
L
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
•
to 9% MeOH in CH Cl ) afforded (R,R)-29 (552 mg, 2.10 mmol,
HRMS (ESI) m/z: [M + Na]+ calcd for C H NaO 337.1991, found
2
2
17 30 5
24
9
5%) as a white solid. Mp: 65−67 °C. [α] +21.4 (c 0.78, MeOH).
337.1989. Anal. Calcd for C H O : C, 64.94; H, 9.62. Found: C,
17 30 5
D
This compound was spectroscopically identical to (S,S)-29. HRMS
64.82; H, 9.61.
Methyl 4-((4S,5S)-2,2-dimethyl-5-(4-oxooctyl)-1,3-dioxolan-4-yl)-
butanoate [(S,S)-32]. Ethereal CH was added dropwise to a
+•
(
ESI) m/z: [M + Na] calcd for C H NaO 285.2042, found
14 30 4
2
85.2028. Anal. Calcd for C H O : C, 64.08; H, 11.52. Found: C,
N
2 2
14
30
4
6
3.98; H, 11.54.
-((4S,5S)-5-(4-Hydroxybutyl)-2,2-dimethyl-1,3-dioxolan-4-yl)-
solution of ketoacid (S,S)-31 (140 mg, 0.45 mmol) in a mixture of
1
MeOH (3 mL) and Et O (2 mL) with stirring at 0 °C until the yellow
2
octan-4-ol [(S,S)-30]. Anhydrous p-TsOH (100 mg, cat.) was added to
a suspension of tetraol (S,S)-29 (492 mg, 1.88 mmol) and 4 Å
molecular sieves in freshly distilled acetone (12 mL) with stirring at
color persisted. The yellow reaction mixture was stirred at 0 °C for 15
min and then was allowed to warm to room temperature with stirring
over a further 15 min. Excess CH N was evaporated under a stream of
2
2
room temperature under a N atmosphere. The reaction mixture was
N2 gas. The colorless reaction mixture was concentrated under
reduced pressure, and the residue was purified by flash column
chromatography (silica gel, 5% to 17% EtOAc in petroleum spirits 40−
60) to afford (S,S)-32 (138 mg, 0.42 mmol, 94%) as a colorless oil.
84% ee (Chiralpak OD column, 2% 2-propanol in n-hexane, flow rate
2
stirred for 19 h then solid NaHCO (300 mg) was added to quench
3
the reaction. The solvent was evaporated in vacuo, and the residue was
purified by flash column chromatography (silica gel, 17% Et O in
2
petroleum spirits 40−60 to 100% Et O) to afford (S,S)-30 (548 mg,
2
2
4
−1
1
.81 mmol, 97%) as a colorless, viscous oil. [α] −25.6 (c 0.77,
MeOH). H NMR (400 MHz, CDCl ): δ 0.87 (t, 3H, J = 7.1 Hz,
D
0.8 mL min , PDA-UV detector 215 nm, retention times: (R,R)-32
1
25
1
3
10.8 min, (S,S)-32 11.2 min). [α]D −16.7 (c 0.55, MeOH). H NMR
CH -14), 1.15−1.65 (m, 26H, incl. 1.34 [s, 6H, 2 × ketal CH ]), 3.58
3
3
(400 MHz, CDCl ): δ 0.88 (t, 3H, J = 7.3 Hz, CH -14), 1.28 (m, 2H),
3
3
(
1
m, 3H, CH-5, CH-6 and CH-10), 3.61 ppm (t, 2H, J = 6.4 Hz, CH -
2
1.33 (s, 6H, 2 × ketal CH ), 1.39−1.93 (m, 10H), 2.28−2.46 (m, 6H,
3
13
). C NMR (100 MHz, CDCl ): (mixture of diastereomers) δ 14.0
3
CH -2, CH -9 and CH -11), 3.56 (m, 2H, CH-5 and CH-6), 3.65 ppm
2
2
2
(
3
C-14), 22.1, 22.3, 22.7, 27.2 (2 × ketal CH ), 27.80, 27.82, 32.42,
13
3
(s, 3H, RCO CH ). C NMR (100 MHz, CDCl ): δ 13.8 (C-14),
2
3
3
2.44, 32.6, 32.7, 37.1, 37.2, 37.27, 37.29, 62.5 (C-1), 71.6 (C-10),
2
0.4, 21.6, 22.3, 25.9, 27.3 (2 × ketal CH ), 32.10, 32.13, 33.9, 42.4,
3
8
0.78, 80.79, 80.81, 80.9, 107.84 (ketal C(CH ) ), 107.85 ppm (ketal
3
2
42.5, 51.5 (RCO CH ), 80.4, 80.6, 108.1 (ketal C(CH ) ), 173.8 (C-
2
3
3
2
+
•
+•
C(CH ) ). GC/MS (EI) m/z: 287 (5, M − CH ), 285 (1, M
−
+•
3
2
3
1), 211.0 ppm (C-10). GC/MS (EI) m/z: 328 (0.2, M ), 313 (17,
OH), 269 (2), 227 (26), 209 (15), 191 (7), 169 (10), 151 (5), 141
7), 135 (12), 129 (2), 121 (18), 115 (7), 109 (24), 101 (5), 100 (15),
5 (25), 87 (5), 85 (87), 79 (23), 73 (4), 69 (48), 67 (40), 59 (69), 57
58), 55 (56), 45 (8), 43 (100), 41 (62). HRMS (ESI) m/z: [M +
+•
M
2
− CH ), 271 (1), 254 (2), 253 (15), 239 (11), 221 (12), 210 (1),
3
(
9
03 (3), 193 (1), 185 (1), 181 (4), 175 (3), 169 (2), 155 (2), 140
(
9
16), 137 (19), 129 (5), 127 (3), 115 (19), 113 (6), 101 (2), 99 (5),
(
+•
+•
8 (14), 93 (12), 87 (2, C H O ), 85 (100, C H O ), 74 (3), 73
+
•
4
7
2
5
9
Na] calcd for C H NaO 325.2355, found 325.2350. Anal. Calcd
+•
+•
17
34
4
(3), 71 (9), 59 (17, C H O ), 57 (41, C H9 ), 55 (31), 43 (49).
2
3
2
4
for C H O : C, 67.51; H, 11.33. Found: C, 67.58; H, 11.44.
+•
17
34
4
HRMS (ESI) m/z: [M + Na] calcd for C H NaO 351.2147, found
18
32
5
1
-((4R,5R)-5-(4-Hydroxybutyl)-2,2-dimethyl-1,3-dioxolan-4-yl)-
3
51.2138. Anal. Calcd for C H O : C 65.82, H 9.82; found: C 65.90,
18 32 5
octan-4-ol [(R,R)-30]. Tetraol (R,R)-29 (461 mg, 1.76 mmol) was
reacted with acetone in the presence of p-TsOH (100 mg, cat.) and 4
H 9.69.
Methyl 4-((4R,5R)-2,2-dimethyl-5-(4-oxooctyl)-1,3-dioxolan-4-yl)-
butanoate [(R,R)-32]. Ketoacid (R,R)-31 (134 mg, 0.43 mmol) was
esterified with CH N in a mixture of MeOH (3 mL) and Et O (2
Å molecular sieves under a N atmosphere over 19 h, as described for
2
the synthesis of (S,S)-30. Purification by flash column chromatography
2
2
2
(
silica gel, 17% Et O in petroleum spirits 40−60 to 100% Et O)
2
2
mL) at 0 °C, as described for the synthesis of (S,S)-32. Purification by
flash column chromatography (silica gel, 5% to 17% EtOAc in
petroleum spirits 40−60) afforded (R,R)-32 (133 mg, 0.40 mmol,
afforded (R,R)-30 (501 mg, 1.66 mmol, 94%) as a colorless, viscous
oil. [α]2 +27.5 (c 0.81, MeOH). This compound was spectroscopi-
4
D
+
•
cally identical to (S,S)-30. HRMS (ESI) m/z: [M + Na] calcd for
C H NaO 325.2355, found 325.2340. Anal. Calcd for C H O : C,
9
5%) as a colorless oil. 81% ee (Chiralpak OD column, 2% 2-propanol
17
34
4
17 34
4
−1
in n-hexane, flow rate 0.8 mL min , PDA-UV detector 215 nm,
6
7.51; H, 11.33. Found: C, 67.57; H, 11.40.
2
5
retention times: (R,R)-32 10.8 min, (S,S)-32 11.2 min). [α]D +18.5 (c
.68, MeOH). This compound was spectroscopically identical to
4
-((4S,5S)-2,2-Dimethyl-5-(4-oxooctyl)-1,3-dioxolan-4-yl)-
0
butanoic acid [(S,S)-31]. A solution of diol (S,S)-30 (373 mg, 1.23
mmol) and PDC (98%, 2.42 g, 6.30 mmol) in DMF (20 mL) was
stirred at room temperature under an Ar atmosphere for 18 h. The
+
•
(
S,S)-32. HRMS (ESI) m/z: [M + Na] calcd for C H NaO
18 32 5
3
9
51.2147, found 351.2133. Anal. Calcd for C H O : C, 65.82; H,
18 32 5
.82. Found: C, 65.81; H, 9.75.
reaction mixture was diluted with Et O (50 mL) and filtered through a
2
Methyl 4-((4S,5S)-5-(4-hydroxyoctyl)-2,2-dimethyl-1,3-dioxolan-
pad of Celite that was washed thoroughly with additional Et O. The
2
4
-yl)butanoate [(S,S)-33]. NaBH (19 mg, 0.50 mmol) was added
4
filtrate was concentrated in vacuo, and the residue was purified by flash
column chromatography (silica gel, 17% EtOAc in petroleum spirits
to a solution of ketoester (S,S)-32 (66 mg, 0.20 mmol) in a mixture of
MeOH (3 mL) and Et O (1 mL) with stirring at 0 °C. The reaction
2
4
0−60 to 100% EtOAc) to afford (S,S)-31 (354 mg, 1.13 mmol, 91%)
25
1
mixture was allowed to warm to room temperature and stirred for a
further 2 h. The solvent was evaporated in vacuo and the residue was
as a colorless, viscous oil. [α] −25.3 (c 0.59, MeOH). H NMR (400
MHz, CDCl ): δ 0.87 (t, 3H, J = 7.3 Hz, CH -14), 1.26 (m, 2H), 1.33
D
3
3
purified by flash column chromatography (silica gel, 17% to 66% Et O
2
(
2
s, 6H, 2 × ketal CH ), 1.42−1.90 (m, 10H), 2.33−2.46 (m, 6H, CH -
3
2
13
in petroleum spirits 40−60) to afford (S,S)-33 (62 mg, 0.19 mmol,
, CH -9 and CH -11), 3.56 ppm (m, 2H, CH-5 and CH-6). C NMR
2 2
9
3%) as a viscous, pale yellow oil. [α]2 −23.8 (c 0.67, MeOH). H
5
1
(
100 MHz, CDCl ): δ 13.8 (C-14), 20.4, 21.3, 22.3, 25.9, 27.2 (2 ×
D
3
NMR (400 MHz, C D ): δ 0.91 (t, 3H, J = 7.0 Hz, CH -14), 1.18−
.67 (m, 20H, incl. 1.42 [s, 3H, ketal CH ], 1.43 [s, 3H, ketal CH ]),
ketal CH ), 31.9, 32.1, 33.8, 42.4, 42.5, 80.4, 80.6, 108.1 (ketal
6
6
3
3
1
C(CH ) ), 178.8 (C-1), 211.2 ppm (C-10). GC/MS (EI) m/z: 314
3
3
3
2
+
•
+•
1.74 (m, 1H), 1.90 (m, 1H), 2.18 (ABX system, 2H, J = 16.1, JAX =
(
1
5
0.03, M ), 299 (3, M − CH ), 221 (8), 140 (5), 137 (11), 127 (1),
19 (4), 113 (2), 100 (10), 99 (1), 87 (3), 85 (44, C H O ), 73 (2),
9 (18, C H O ), 57 (43, C H9 ), 45 (10), 43 (100). HRMS (ESI)
m/z: [M + Na] calcd for C H NaO 337.1991, found 337.2000.
2 AB
3
+•
7.5, JBX = 7.1 Hz, CH -2), 3.37 ppm (s, 3H, RCO CH ), 3.42 (m, 1H,
2 2 3
5
9
13
+
•
+•
CH-10), 3.57 ppm (m, 2H, CH-5 and CH-6). C NMR (100 MHz,
C D ): (mixture of diastereomers) δ 14.3 (C-14), 22.1, 22.8, 23.0,
2
3
2
4
+
•
6
6
17
30
5
2
3
3.1, 27.57 (ketal CH ), 27.61 (ketal CH ), 28.2, 32.39, 32.41, 33.16,
Anal. Calcd for C H O : C, 64.94; H, 9.62. Found: C, 64.73; H, 9.62.
3
3
17
30
5
3.19, 33.8, 37.74, 37.78, 37.82, 37.9, 50.9 (RCO CH ), 71.4 (C-10),
4
-((4R,5R)-2,2-Dimethyl-5-(4-oxooctyl)-1,3-dioxolan-4-yl)-
2
3
butanoic acid [(R,R)-31]. Diol (R,R)-30 (368 mg, 1.22 mmol) was
oxidized with PDC (98%, 2.46 g, 6.41 mmol) in DMF (20 mL) under
an Ar atmosphere over 18 h, as described for the synthesis of (S,S)-31.
Purification by flash column chromatography (silica gel, 17% EtOAc in
petroleum spirits 40−60 to 100% EtOAc) afforded (R,R)-31 (362 mg,
71.5 (C-10), 81.0 (2C), 81.2, 81.3, 108.06 (ketal C(CH ) ), 108.07
3 2
(ketal C(CH
315 (3, M − CH
)
), 173.19 (C-1), 173.21 ppm (C-1). GC/MS (EI) m/z:
3
2
+
•
+•
), 313 (2, M − OH), 256 (4), 255 (26), 237 (5),
3
223 (23), 215 (2), 205 (18), 197 (7), 187 (12), 177 (14), 163 (12),
157 (6), 137 (11), 129 (4), 121 (22), 115 (32), 109 (18), 101 (5), 95
(25), 87 (6), 85 (56), 81 (24), 74 (7), 73 (7), 69 (30), 59 (41,
1
.15 mmol, 95%) as a colorless, viscous oil. [α] 2D 5 +27.2 (c 0.66,
+•
+•
MeOH). This compound was spectroscopically identical to (S,S)-31.
C H O ), 57 (35, C H9 ), 55 (55), 43 (100). HRMS (ESI) m/z:
2
3
2
4
M
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
M + Na]+ calcd for C H NaO : 353.2304, found 353.2295. Anal.
•
CH-5 of lactone (R,R)-8). 13C NMR (125 MHz, CDCl ): (mixture of
[
18
34
5
3
Calcd for C H O : C, 65.42; H, 10.37. Found: C, 65.41; H, 10.34.
diastereomers; appears to primarily contain lactone (R,R)-8) δ 14.0
(C-14), 18.4, 21.4, 21.6, 22.7, 24.1, 25.4, 26.1, 26.3, 26.7, 26.9, 27.8
(br), 29.6, 29.7, 30.1, 30.28, 30.32, 32.3, 32.5, 32.8 (br), 34.0, 36.9,
37.1 (br), 37.2 (br), 37.27, 37.32, 58.48, 58.54, 62.66, 62.70, 64.2, 70.1,
70.75, 70.81, 71.57, 71.65, 71.7 (br), 72.1, 72.5, 72.6, 72.8, 73.2 (br),
83.2 and 83.3 (C-5 of lactone (R,R)-8), 171.5 (C-1 of lactone (R,R)-
18
34
5
Methyl 4-((4R,5R)-5-(4-hydroxyoctyl)-2,2-dimethyl-1,3-dioxolan-
-yl)butanoate [(R,R)-33]. Ketoester (R,R)-32 (73 mg, 0.22 mmol)
4
was reduced with NaBH (21 mg, 0.56 mmol) in a mixture of MeOH
4
(
3 mL) and Et O (1 mL) over 2 h, as described for the synthesis of
2
(S,S)-33. Purification by flash column chromatography (silica gel, 17%
to 66% Et O in petroleum spirits 40−60) afforded hydroxyester (R,R)-
8), 173.9 ppm (C-1 of ester (R,R)-9). GC/MS (EI) m/z:
2
2
5
+•
3
3 (68 mg, 0.21 mmol, 93%) as a viscous, pale yellow oil. [α] +21.7
(dihydroxylactone (R,R)-8) 240 (0.1, M − H O), 238 (2), 221
D
2
(
(
3
1
c 0.52, MeOH). This compound was spectroscopically identical to
(1), 207 (1), 196 (1), 183 (19), 165 (15), 159 (3), 157 (3), 154 (6),
143 (1), 141 (41), 137 (18), 129 (13), 123 (53), 119 (31), 115 (1),
111 (13), 101 (12), 100 (75), 99 (34), 87 (5), 81 (64), 71 (59), 67
(44), 57 (58, C H9 ), 55 (100), 43 (74), 41 (82). HRMS (ESI) m/z:
(R,R)-8: [M + Na] calcd for C H NaO : 281.1729, found
14 26 4
+
•
S,S)-33. HRMS (ESI) m/z: [M + Na] calcd for C H NaO :
18
34
5
53.2304, found 353.2299. Anal. Calcd for C H O : C, 65.42; H,
18
34
5
+•
0.37. Found: C, 65.38; H, 10.38.
4
+
•
(
S)-6-((1S)-1,5-Dihydroxynonyl)-tetrahydropyran-2-one [(S,S)-8]
and Methyl (5S,6S)-5,6,10-trihydroxytetradecanoate [(S,S)-9]. Am-
berlyst 15 ion-exchange resin (cat.) was added to a solution of (S,S)-33
+•
2
81.1720; (R,R)-9: [M + Na] calcd for C H NaO : 313.1991,
15 30 5
found 313.1996.
(
27.6 mg, 83.5 μmol) in a mixture of anhydrous THF (1 mL) and
Synthesis of Deuterium-Labeled Threo Dihydroxylactones/
2
2
MeOH (2 mL). The reaction mixture was stirred at 70 °C for 12 h and
then allowed to cool to room temperature. The mixture was filtered
through a pad of anhydrous Na SO and concentrated in vacuo. The
Trihydroxyesters [ H ]-(S,S)-8/9 and [ H ]-(R,R)-8/9. Methyl 4-
4
4
2
2
((4S,5S)-2,2-dimethyl-5-([3- H ,5- H ]-4-oxooctyl)-1,3-dioxo-
lan-4-yl)butanoate ([ H
mmol) was added to D O (99.9 atom % D, 5 mL) at 0 °C, and the
0
;1;2
0;1;2
2
]-(S,S)-32). Sodium metal (∼200 mg, 8.70
2
4
4
residue was dissolved in a mixture of MeOH (2 mL) and Et O (2 mL),
2
2
and ethereal CH N2 was added dropwise until the yellow color
resulting NaOD solution was added to a solution of ketoacid (S,S)-31
(127 mg, 0.40 mmol) in anhydrous THF (1.5 mL). The pale yellow
reaction mixture was stirred at room temperature for 28 days and then
solid oxalic acid (∼2.3 g, 25.55 mmol) was added to acidify the basic
2
persisted. The yellow reaction mixture was stirred for 30 min and then
excess CH N was evaporated under a stream of N gas. The colorless
2
2
2
reaction mixture was concentrated in vacuo to afford a mixture of
dihydroxylactone (S,S)-8 and trihydroxyester (S,S)-9 (23.1 mg, 79.5
μmol, 95% assuming all the product was (S,S)-9) as a viscous, pale
reaction mixture. The acidic mixture was extracted with Et O (6 × 20
2
mL) and the combined organic extract was washed with brine (8 × 20
mL) until the aqueous wash obtained was neutral. The organic layer
yellow oil. [α]2 −14.5 (c 0.15, CH CN). H NMR (500 MHz,
5
1
D
3
CDCl ): δ 0.89 (t, 3H, J = 7.0 Hz, CH -14), 1.20−2.66 (m, ∼18H,
incl. 2.34 [apparent q, 1.2H, J = 7.0 Hz, CH -2]), 3.39 (m, 2.7H), 3.59
was dried over anhydrous MgSO , filtered and concentrated in vacuo,
3
3
4
2
affording ketoacid [ H ]-(S,S)-31 as the major deuterium-labeled
2
4
2
(
(
(
m, 1.5H), 3.66 (s, 1.1H, RCO CH of ester (S,S)-9), 4.08 ppm
apparent t, 0.5H, J = 6.4 Hz, CH-5 of lactone (S,S)-8). C NMR
product (≤1% [ H ]).
2
3
0
13
2
2
4-((4S,5S)-2,2-Dimethyl-5-([3- H ,5- H0;1;2]-4-oxooctyl)-1,3-di-
0;1;2
2
125 MHz, CDCl ): (mixture of diastereomers; also contains (5S,6S)-
oxolan-4-yl)butanoic acid ([ H
(0.04, M ), 303 (3, M − CH
4
]-(S,S)-31). GC/MS (EI) m/z: 318
), 301 (1), 243 (2), 225 (2), 201 (1),
197 (1), 187 (1), 183 (2), 173 (1), 158 (5), 139 (16), 131 (2), 121
3
+
•
+•
5
2
2
3
3
7
7
8
1
,6,10-trihydroxytetradecanoic acid [(S,S)-34]) δ 14.0 (C-14), 18.4,
0.88, 20.91, 21.47, 21.54, 21.55, 21.65, 22.7, 24.1, 25.4, 26.1, 26.3,
6.7, 26.9, 27.2, 27.9 (br), 28.7, 29.6, 29.7, 30.1, 30.28, 30.32, 32.4,
2.8 (br), 33.1, 33.3, 33.7, 34.0, 36.8, 36.86, 36.90, 37.1 (br), 37.2,
7.3, 51.6 (RCO CH of ester (S,S)-9), 58.5, 58.6, 62.66, 62.70, 64.2,
3
+
•
(12), 117 (1), 103 (1), 100 (28), 93 (9), 87 (42, C
H
D
O
2
and/or
and/or
5
7
2
+
•
•
+•
C
C
H
O
O
), 79 (9), 73 (7), 71 (10), 59 (70, C
), 55 (39), 45 (15), 43 (100).
H
D
4
7
2
4
7
+
H
3
2
3
2
2
2
0.1, 70.6, 70.76, 70.82, 71.56, 71.64, 71.7 (br), 72.1, 72.5, 72.6, 72.7,
3.19, 73.21, 73.4, 73.5, 73.8 (br), 74.0 (br), 74.1 (br), 74.25, 74.29,
3.2, and 83.4 (C-5 of lactone (S,S)-8), 171.6 (C-1 of lactone (S,S)-8),
73.9 (C-1 of ester (S,S)-9), 174.3 ppm (C-1 of acid (S,S)-34). GC/
The crude [ H
4
]-(S,S)-31 was dissolved in a mixture of MeOH (3
mL) and Et
O (2 mL) and the solution was cooled to 0 °C. Ethereal
2
CH was added dropwise until the yellow color of the reaction
N
2
2
mixture persisted. The yellow solution was stirred at 0 °C for 15 min
and then allowed to warm to room temperature with stirring over a
+
•
MS (EI) m/z: (dihydroxylactone (S,S)-8) 240 (0.1, M − H O), 238
2
(
2), 221 (1), 207 (1), 196 (1), 183 (23), 165 (16), 159 (3), 157 (3),
further 15 min. Excess CH N was evaporated under a stream of N
2
2
2
154 (7), 143 (1), 141 (46), 137 (19), 129 (14), 123 (57), 119 (32),
gas. The colorless reaction mixture was concentrated in vacuo and the
residue was purified by flash column chromatography (silica gel, 25%
1
15 (1), 111 (14), 101 (11), 100 (79), 99 (36), 87 (5), 81 (68), 71
+
•
(
(
60), 67 (45), 57 (59, C H9 ), 55 (100), 43 (76), 41 (82). HRMS
ESI) m/z: (S,S)-8: [M + Na] calcd for C H NaO : 281.1729,
to 66% Et O in petroleum spirits 40−60) to afford a pale yellow oil
2
2
4
+•
containing [ H ]-(S,S)-32 (122 mg, 0.37 mmol, 91% over 2 steps,
4
14
26
4
+
•
2
25
found 281.1717; (S,S)-9: [M + Na] calcd for C H NaO :
≤1% [ H
0.55, MeOH). H NMR (500 MHz, CDCl
CH -14), 1.28 (m, 2H), 1.33 (s, 6H, 2 × ketal CH
10H), 2.33 (ABX system, 2H, JAB = 16.2, JAX = 7.5, JBX = 7.3 Hz, CH
2), 2.38−2.44 (m, 0.1H, residual hydrogen from CH or CHD at C-9
]-analogues), 3.55 (m, 2H, CH-5 and CH-
0
]) as the major deuterium-labeled product. [α]
D
−21.7 (c
): δ 0.87 (t, 3H, J = 7.4 Hz,
), 1.38−1.94 (m,
1
5
30
5
1
313.1991. Found: 313.1976.
3
Sodium (5S,6S)-5,6,10-trihydroxytetradecanoate [(S,S)-35]. A
3
3
small amount of the (S,S)-8/9/34 mixture was treated with NaOD
2
-
2
1
in D O and analyzed by NMR. H NMR (400 MHz, D O/1,4-
2
2
2
2
2
dioxane): δ 0.87 (t, 3H, J = 6.9 Hz, CH -14), 1.22−1.76 (m, 18H),
and/or C-11 of [ H
6), 3.64 ppm (s, 3H, RCO
14.0 (C-14), 20.4, 21.7, 22.4, 25.9, 27.4 (2 × ketal CH
41.4−42.3 (m, incl. 41.8 [quintet, JC,D = 18.4 Hz, CD ], 41.9 [quintet,
C,D = 18.5 Hz, CD ], C-9 and C-11), 51.6 (RCO CH ), 80.6, 80.7,
108.2 (ketal C(CH ), 173.9 (C-1), 211.3 (minor singlet from β-shift,
0 3
]-[ H
3
13
2
3
.20 (ABX system, 2H, J = 14.9, J = 7.2, J = 7.1 Hz, CH -2),
.51 (m, 2H, CH-5 and CH-6), 3.67 ppm (m, 1H, CH-10). C NMR
2
CH
3
). C NMR (125 MHz, CDCl
3
): δ
2
AB
AX
BX
2
13
), 32.2, 34.0,
3
(
100 MHz, D O/1,4-dioxane): (mixture of diastereomers) δ 14.0 (C-
2
2
1
(
4), 21.6, 21.7, 22.7, 22.8, 27.6, 32.5, 32.6, 36.2, 36.4, 36.5, 38.0, 72.1
C-10), 72.2 (C-10), 74.2, 74.26, 74.30, 74.4, 184.2 ppm (C-1).
R)-6-((1R)-1,5-Dihydroxynonyl)-tetrahydropyran-2-one [(R,R)-8]
J
2
2
3
)
3 2
2
2
(
C-10 of [ H ]-analogues), 211.4 ppm (C-10 of [ H ]-(S,S)-32). GC/
3
4
+
•
+•
and Methyl (5R,6R)-5,6,10-trihydroxytetradecanoate [(R,R)-9]. As
described for the synthesis of (S,S)-8/9 from (S,S)-33, acid-catalyzed
ketal methanolysis of (R,R)-33 (27.4 mg, 82.9 μmol) and treatment
MS (EI) m/z: 332 (0.2, M ), 317 (19, M − CH ), 275 (1), 258 (3),
3
257 (16), 243 (11), 225 (9), 215 (1), 207 (2), 197 (2), 187 (1), 183
(5), 179 (2), 173 (2), 155 (2), 144 (19), 140 (19), 131 (3), 129 (9),
117 (1), 115 (25), 103 (1), 102 (6), 101 (9), 93 (10), 87 (100,
with CH N2 afforded a mixture of dihydroxylactone (R,R)-8 and
2
+
•
+•
trihydroxyester (R,R)-9 (22.0 mg, 75.8 μmol, 91% assuming all the
C H D O and/or C H O ), 74 (4), 73 (7), 71 (9), 59 (60,
5 7 2 4 7 2
2
5
+•
+•
product was (R,R)-9) as a viscous, pale yellow oil. [α] +12.9 (c 0.13,
C H D and/or C H O ), 55 (23), 43 (56). HRMS (ESI) m/z:
4 7 2 2 3 2
[M + Na] calcd for C H D NaO : 355.2399, found 355.2404.
Methyl 4-((4R,5R)-2,2-dimethyl-5-([3- H ,5- H ]-4-oxooctyl)-
1,3-dioxolan-4-yl)butan-oate ([ H ]-(R,R)-32). As described for the
D
1
+•
CH CN). H NMR (500 MHz, CDCl ): δ 0.87 (t, 3H, J = 6.8 Hz,
3
3
18 28 4 5
2
2
CH -14), 1.20−2.66 (m, ∼19H, incl. 2.33 [apparent t, 1.0H, J = 7.0
3
0;1;2
0;1;2
2
Hz, CH -2]), 3.40 (m, 4.5H), 3.59 (m, 1.7H), 3.64 (s, 0.4H,
2
4
2
RCO CH of ester (R,R)-9), 4.07 ppm (apparent t, 0.8H, J = 6.4 Hz,
synthesis of [ H ]-(S,S)-32, ketoacid (R,R)-31 (123 mg, 0.39 mmol)
2
3
4
N
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
2
2
was deuterated with NaOD/D O over 28 days to provide [ H ]-(R,R)-
83.0, 83.2, 83.3, 171.5 (C-1 of lactone [ H ]-(S,S)-8), 173.9* (C-1 of
4
2 2
2
4
2
2
3
1 as the major product (≤1% [ H ]). The crude [ H ]-(R,R)-31 was
then esterified with CH N . Purification by flash column chromatog-
raphy (silica gel, 25% to 66% Et O in petroleum spirits 40−60)
afforded a pale yellow oil that contained [ H ]-(R,R)-32 (121 mg, 0.36
ester [ H ]-(S,S)-9), 174.3* ppm (C-1 of acid [ H ]-(S,S)-34). GC/
4 4
2
0
4
+•
MS (EI) m/z: (dihydroxylactone [ H ]-(S,S)-8) 244 (0.1, M
−
2
2
4
H O), 241 (3), 226 (0.4), 218 (1), 207 (1), 199 (1), 193 (1), 185
2
2
2
(26), 174 (1), 167 (10), 163 (3), 157 (2), 156 (7), 145 (50), 143 (3),
138 (20), 133 (1), 129 (16), 126 (55), 121 (26), 119 (4), 111 (17),
105 (2), 101 (42), 100 (87), 99 (45), 89 (5), 83 (55), 73 (27), 71
4
2
mmol, 93% over 2 steps, ≤1% [ H ]) as the major deuterium-labeled
0
product. [α]2 +21.3 (c 0.48, MeOH). This compound was
5
D
2
+•
spectroscopically identical to [ H ]-(S,S)-32. HRMS (ESI) m/z: [M
Na] calcd for C H D NaO : 355.2399, found 355.2404.
Methyl 4-((4S,5S)-5-([3- H ,5- H ]-4-hydroxyoctyl)-2,2-di-
methyl-1,3-dioxolan-4-yl)butanoate ([ H ]-(S,S)-33). Ketoester
H ]-(S,S)-32 (76 mg, 0.23 mmol) was reduced with NaBH (18
mg, 0.48 mmol) in a mixture of MeOH (3 mL) and Et O (1 mL) over
h, as described for the synthesis of (S,S)-33. Purification by flash
column chromatography (silica gel, 17% to 66% Et O in petroleum
(85), 59 (37, C H D ), 57 (66), 55 (86), 43 (100), 41 (68). HRMS
4
4
7
2
+
•
2
+•
+
(ESI) m/z: [ H ]-(S,S)-8: [M + Na] calcd for C H D NaO :
18
28
4
5
4
14 22
4
4
2
2
2
+•
285.1980, found 285.1945; [ H ]-(S,S)-9: [M + Na] calcd for
C H D NaO : 317.2242; found: 317.2210.
0
;1;2
0;1;2
4
2
4
15 26
4
5
2
2
2
[
(R)-6-([4- H ,6- H ]-(1R)-1,5-Dihydroxynonyl)-tetrahydropyr-
0;1;2 0;1;2
2 2 2
4
4
an-2-one ([ H ]-(R,R)-8) and Methyl [9- H ,11- H ]-(5R,6R)-
4 0;1;2 0;1;2
2
2
2
5,6,10-trihydroxytetradecanoate ([ H
]-(R,R)-9). As described for
4
the synthesis of (S,S)-8/9 from (S,S)-33, acid-catalyzed ketal
2
2
2
spirits 40−60) afforded a viscous, pale yellow oil that contained [ H ]-
methanolysis of [ H
with CH
mixture of dihydroxylactone [ H
4
]-(R,R)-33 (20.9 mg, 62.5 μmol) and treatment
afforded a viscous, pale yellow oil that contained a
]-(R,R)-8 and trihydroxyester [ H
(R,R)-9 (16.9 mg, 57.4 μmol, 92% assuming all the product was [ H
4
2
(
S,S)-33 (74 mg, 0.22 mmol, 97%, ≤1% [ H ]) as the major
2
N
2
0
2
5
1
2
2
deuterium-labeled product. [α] −30.2 (c 0.67, MeOH). H NMR
4
4
]-
D
2
(
500 MHz, C D ): δ 0.91 (t, 3H, J = 7.0 Hz, CH -14), 1.19−1.65 (m,
4
]-
6
6
3
2
23
1
6H, incl. 1.425 [s, 3H, ketal CH ], 1.432 [s, 3H, ketal CH ]), 1.73
(R,R)-9, ≤1% [ H
+14.1 (c 0.15, CH
= 6.9 Hz, CH -14), 1.20−2.66 (m, ∼15H, incl. 2.34 [apparent q, 1.7H,
J = 6.9 Hz, CH -2), 3.34−3.46 (m, 2.4H, incl. 3.37 [t, J = 6.2 Hz]),
3.56 (m, 1H), 3.65 (s, 1.5H, RCO
ppm (apparent t, 0.6H, J = 6.4 Hz, CH-5 of lactone [ H
0
]) as the major deuterium-labeled products. [α]
D
3
3
1
(
m, 1H), 1.90 (m, 1H), 2.18 (ABX system, 2H, JAB = 16.1, JAX = 7.4,
JBX = 7.2 Hz, CH -2), 3.36 (s, 3H, RCO CH ), 3.40 (m, 1H, CH-10),
.57 ppm (m, 2H, CH-5 and CH-6). C NMR (125 MHz, C D ):
mixture of diastereomers) δ 14.3 (C-14), 22.1, 22.6, 22.8, 23.1, 27.57
CN). H NMR (500 MHz, CDCl ): δ 0.88 (t, 3H, J
3 3
2
2
2
3
3
1
3
3
2
6
6
2
(
(
3
7
(
3
CH of ester [ H ]-(R,R)-9), 4.07
2 3 4
2
ketal CH ), 27.61 (ketal CH ), 28.0, 32.38, 32.40, 33.11, 33.14, 33.8,
4
]-(R,R)-8).
C NMR (125 MHz, CDCl ): (mixture of diastereomers; appears to
3
3
3
13
6.4−37.4 (br m, C-9 and C-11), 50.9 (RCO CH ), 71.19 (C-10),
2
3
2
2
1.25 (C-10), 81.0 (2C), 81.2, 81.3, 108.1 (ketal C(CH ) ), 173.19
contain mostly ester [ H
4
]-(R,R)-9 and [ H ]-(5R,6R)-5,6,10-trihy-
droxytetradecanoic acid [ H ]-(R,R)-34; * denotes major signals) δ
4
14.1* (C-14), 20.85*, 20.88*, 21.4*, 21.5*, 21.6*, 22.7*, 24.07,
24.09*, 25.4*, 26.1*, 26.3, 26.9, 27.3, 27.6*, 28.7, 29.63, 29.67*, 30.3,
4
3
2
+
•
2
C-1), 173.21 ppm (C-1). GC/MS (EI) m/z: 319 (3, M − CH ),
3
+
•
17 (2, M − OH), 260 (4), 259 (29), 245 (2), 240 (4), 229 (1), 227
(
17), 215 (1), 208 (9), 199 (5), 190 (7), 180 (9), 167 (16), 157 (6),
1
1
43 (12), 139 (11), 133 (2), 131 (12), 121 (13), 115 (42), 111 (13),
05 (2), 101 (8), 95 (13), 89 (4), 87 (47), 83 (22), 74 (9), 73 (12), 71
30.4, 31.9, 32.7, 32.9* (br), 33.1*, 33.3*, 33.7*, 33.9, 34.0*, 35.7−37.0
2
(br m, C-9 and C-11), 51.5 (RCO
CH
of ester [ H
]-(R,R)-9), 58.5*,
2
3
4
+•
+•
(
(
3
33), 59 (59, C H D and/or C H O ), 55 (37), 43 (100). HRMS
ESI) m/z: [M + Na] calcd for C H D O Na: 357.2555, found
57.2558.
58.6*, 62.7, 64.2*, 70.77, 70.84, 71.50*, 71.54*, 72.2*, 72.5, 73.5,
4
7
2
2
3
2
+
•
73.8* (br), 74.0* (br), 74.1*, 74.2*, 74.26*, 74.29*, 80.5, 80.7, 80.8,
1
8
30
4
5
2
82.9 and 83.0 (C-5 of lactone [ H
[ H
]-(R,R)-8), 173.9* (C-1 of ester
4
2
2
2
2
Methyl 4-((4R,5R)-5-([3- H ,5- H ]-4-hydroxyoctyl)-2,2-di-
]-(R,R)-9), 174.3* ppm (C-1 of acid [ H ]-(R,R)-34). GC/MS
4 4
2
0
;1;2
0;1;2
2
+•
methyl-1,3-dioxolan-4-yl)-butanoate ([ H ]-(R,R)-33). Ketoester
(EI) m/z: (dihydroxylactone [ H ]-(R,R)-8) 244 (0.1, M − H O),
4
4
2
2
[
H ]-(R,R)-32 (85 mg, 0.26 mmol) was reduced with NaBH (20
241 (3), 226 (0.4), 218 (1), 207 (1), 199 (1), 193 (1), 185 (26), 174
(1), 167 (10), 163 (3), 157 (2), 156 (8), 145 (50), 143 (3), 138 (22),
133 (1), 129 (16), 126 (58), 121 (26), 119 (4), 111 (18), 105 (2), 101
(43), 100 (90), 99 (48), 89 (5), 83 (56), 73 (26), 71 (85), 59 (38,
4
4
mg, 0.53 mmol) in a mixture of MeOH (3 mL) and Et O (1 mL) over
2
column chromatography (silica gel, 17% to 66% Et O in petroleum
2
h, as described for the synthesis of (S,S)-33. Purification by flash
2
2
+•
spirits 40−60) afforded a viscous, pale yellow oil that contained [ H ]-
C H D ), 57 (66), 55 (88), 43 (100), 41 (66). HRMS (ESI) m/z:
4
4
7
2
2
2
+•
(
R,R)-33 (84 mg, 0.25 mmol, 98%, ≤1% [ H ]) as the major
[ H ]-(R,R)-8: [M + Na] calcd for C H D NaO : 285.1980, found
285.1939; [ H ]-(R,R)-9: [M + Na] calcd for C H D NaO :
0
4
14 22
4
4
2
5
2
+•
deuterium-labeled product. [α] +29.7 (c 0.59 in MeOH). This
D
4
15 26
4
5
2
compound was spectroscopically identical to [ H ]-(S,S)-33. HRMS
317.2242, found 317.2205.
4
+
•
(
ESI) m/z: [M + Na] calcd for C H D O Na: 357.2555, found
Synthesis of Dihydroxylactones/Trihydroxyesters erythro-8/
18
30
4
5
2
357.2543.
9 and [ H
yloxy)tetrahydro-2H-pyran [(Z)-36]. A mixture of alkyne 17 (737
mg, 1.84 mmol) and Lindlar’s catalyst (5% Pd/CaCO poisoned with
4
]-erythro-8/9. (Z)-2-(10-(Benzyloxy)tetradec-5-en-1-
(
S)-6-([4- H ;1;2,6-2H0;1;2]-(1S)-1,5-Dihydroxynonyl)-tetrahydropyr-
0
2 2 2
2
an-2-one ([ H ]-(S,S)-8) and Methyl [9- H ,11- H ]-(5S,6S)-
5
3
4
0;1;2
0;1;2
2
,6,10-trihydroxytetradecanoate ([ H ]-(S,S)-9). As described for
Pb, 120 mg) in EtOAc (10 mL) was degassed-purged twice with N2
4
the synthesis of (S,S)-8/9 from (S,S)-33, acid-catalyzed ketal
(g) and then twice with H (g). The reaction mixture was stirred
2
2
methanolysis of [ H ]-(S,S)-33 (30.1 mg, 90.0 μmol) and treatment
under a H atmosphere at room temperature for 4 h and then was
4
2
with CH N2 afforded a viscous, pale yellow oil that contained a
filtered through a pad of Celite that was washed thoroughly with
additional EtOAc. The solvent was removed in vacuo and the crude
product was purified by flash column chromatography (silica gel, 100%
2
2
2
mixture of dihydroxylactone [ H ]-(S,S)-8 and trihydroxyester [ H ]-
4
4
2
(
(
−
S,S)-9 (25.4 mg, 86.3 μmol, 96% assuming all the product was [ H ]-
S,S)-9, ≤1% [ H ]) as the major deuterium-labeled products. [α]
11.8 (c 0.10, CH CN). H NMR (500 MHz, CDCl ): δ 0.87 (t, 3H,
4
2
23
D
n-hexane to 2% EtOAc in n-hexane) to afford the alkene (Z)-36 (625
0
1
1
mg, 1.55 mmol, 84%) as a colorless oil. H NMR (400 MHz, CDCl ):
3
3
3
J = 6.8 Hz, CH -14), 1.18−2.66 (m, ∼15H, incl. 2.33 [apparent t,
δ 0.88 (t, 3H, J = 7.0 Hz, CH -14), 1.22−1.65 (m, 18H), 1.69 (m,
3
3
1
.2H, J = 6.9 Hz, CH -2), 3.32−3.44 (m, 2.3H, incl. 3.37 [t, J = 6.2
1H), 1.82 (m, 1H), 2.03 (m, 4H, CH -4 and CH -7), 3.36 (m, 2H,
2
2
2
2
Hz]), 3.56 (m, 1H), 3.64 (s, 0.8H, RCO CH of ester [ H ]-(S,S)-9),
CH-1 and CH-10), 3.48 (m, 1H, CH-6′), 3.72 (dt, 1H, J = 9.6, 6.8 Hz,
2
3
4
2
4
8
.07 ppm (apparent t, 0.8H, J = 6.4 Hz, CH-5 of lactone [ H ]-(S,S)-
). C NMR (125 MHz, CDCl ): (mixture of diastereomers; also
contains [ H ]-(5S,6S)-5,6,10-trihydroxytetradecanoic acid [ H ]-
CH-1), 3.85 (m, 1H, CH-6′), 4.48 (s, 2H, ROCH Ph), 4.56 (dd, 1H, J
4
2
13
= 4.2, 2.8 Hz, CH-2′), 5.35 (m, 2H, CH-5 and CH-6), 7.21−7.35 ppm
3
2
2
13
(m, 5H, Ar-H). C NMR (100 MHz, CDCl ): δ 14.1 (C-14), 19.7,
4
4
3
(S,S)-34; * denotes major signals) δ 14.1* (C-14), 18.4, 20.87*,
22.9, 25.45, 25.51, 26.4, 27.1, 27.3, 27.6, 29.4, 30.8, 33.5, 33.6, 62.3 (C-
2
2
3
0.89*, 21.2, 21.3, 21.5, 22.5, 22.7*, 24.07, 24.09, 24.13, 25.4*, 26.1*,
7.3, 27.6*, 28.7, 29.63, 29.67*, 30.3, 31.9, 32.1, 32.3, 32.5, 32.6, 32.7,
6′), 67.5 (C-1), 70.7 (ROCH Ph), 79.0 (C-10), 98.8 (C-2′), 127.3 (Ar
2
CH), 127.7 (2 × Ar CH), 128.3 (2 × Ar CH), 129.8 (RHCCHR),
129.9 (RHCCHR), 139.2 ppm (Ar C). GC/MS (EI) m/z: 318 (1),
227 (1), 210 (2), 191 (1), 153 (1), 135 (2), 121 (1), 107 (3), 101 (2),
2.8* (br), 33.1*, 33.3*, 33.7*, 33.9, 34.0*, 35.7−37.0 (br m, C-9 and
2
C-11), 51.5 (RCO CH of ester [ H ]-(S,S)-9), 58.5, 58.6*, 64.2*,
2
3
4
+
•
+•
71.30, 71.37, 71.44*, 71.49*, 71.53*, 72.14*, 73.2, 73.47, 73.49, 73.8*
91 (64, C H7 ), 85 (100, THP ), 77 (1), 67 (16), 57 (9), 55 (15),
7
+
•
(
br), 74.0* (br), 74.1*, 74.25*, 74.28, 80.48, 80.51, 80.7, 80.8, 82.9,
43 (14), 41 (21). HRMS (ESI) m/z: [M + Na] calcd for
O
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
C H NaO : 425.3032, found 425.3017. Anal. Calcd for C H O : C,
(100 MHz, CD OD): (mixture of diastereomers) δ 14.4 (C-14), 23.2,
26
42
3
26 42
3
3
7
7.56; H, 10.51. Found: C, 77.20; H, 10.80.
23.3, 23.8, 29.1, 33.4, 33.6, 33.7, 38.1, 38.2, 38.4, 38.5, 63.0 (C-1),
72.37, 72.43, 75.88, 75.93 ppm. HRMS (ESI) m/z: [M + Na]+ calcd
for C H NaO : 285.2042, found 285.2027. Anal. Calcd for
•
(
5,6-erythro)-10-(Benzyloxy)-1-(tetrahydro-2H-pyran-2-yloxy)-
tetradecane-5,6-diol (erythro-37). OsO (2.5% w/v in t-BuOH, 3.0
mL, 0.30 mmol) was added dropwise to a solution of NMO (97%, 457
mg, 3.78 mmol) and alkene (Z)-36 (1.187 g, 2.95 mmol) in a mixture
of THF (10 mL) and H O (1 mL). The orange reaction mixture was
4
14 30
4
C H O : C, 64.08; H, 11.52. Found: C, 64.04; H, 11.33.
14 30 4
1-((4,5-erythro)-5-(4-Hydroxybutyl)-2,2-dimethyl-1,3-dioxolan-4-
yl)octan-4-ol (erythro-30). Tetraol erythro-29 (375 mg, 1.43 mmol)
was reacted with acetone in the presence of p-TsOH (100 mg, cat.)
and 4 Å molecular sieves under a N2 atmosphere over 18 h, as
described for the synthesis of (S,S)-30. Purification by flash column
2
stirred at room temperature for 96 h. A solution of sodium sulfite
(
∼1.0 g, 7.93 mmol) in H O (10 mL) was added to quench the
2
reaction and the mixture was extracted with Et O (6 × 40 mL). The
combined organic extract was washed with aqueous NaOH solution
2
chromatography (silica gel, 33% Et O in petroleum spirits 40−60 to
2
(
5%, 2 × 40 mL) and brine (40 mL), dried over anhydrous MgSO4,
100% Et O) afforded erythro-30 (420 mg, 1.39 mmol, 97%) as a
2
1
filtered and concentrated in vacuo. The crude product was purified by
colorless, viscous oil. H NMR (400 MHz, CDCl ): δ 0.89 (t, 3H, J =
3
flash column chromatography (silica gel, 33% Et O in petroleum
7.0 Hz, CH -14), 1.21−1.70 (m, 26H, incl. 1.31 [s, 3H, ketal CH ],
2
3
3
spirits 40−60 to 100% Et O) to afford racemic erythro-37 (1.160 g,
1.41 [s, 3H, ketal CH ]), 3.59 (m, 1H, CH-10), 3.64 (t, 2H, J = 6.1 Hz,
2
3
1
13
2
.66 mmol, 90%) as a viscous, yellow oil. H NMR (400 MHz,
CH -1), 4.02 ppm (m, 2H, CH-5 and CH-6). C NMR (100 MHz,
2
CDCl ): δ 0.88 (t, 3H, J = 7.0 Hz, CH -14), 1.22−2.10 (m, 26H), 3.38
CDCl ): (mixture of diastereomers) δ 14.1 (C-14), 22.3, 22.49, 22.51,
3
3
3
(
m, 2H, CH-1 and CH-10), 3.48 (m, 1H, CH-6′), 3.56 (m, 2H, CH-5
22.53, 22.7, 25.95 (ketal CH ), 25.96 (ketal CH ), 27.8, 28.6 (ketal
3
3
and CH-6), 3.74 (m, 1H, CH-1), 3.85 (m, 1H, CH-6′), 4.48 (m, 2H,
CH ), 29.39, 29.44, 29.7, 32.6, 37.1, 37.25, 37.31, 37.4, 62.8 (C-1),
3
ROCH Ph), 4.55 (dd, 1H, J = 4.4, 2.7 Hz, CH-2′), 7.21−7.36 ppm (m,
71.7 (C-10), 71.8 (C-10), 77.90, 77.93, 77.95, 107.4 ppm (ketal
2
13
+•
+•
5
H, Ar-H). C NMR (100 MHz, CDCl ): (mixture of diastereomers)
C(CH ) ). GC/MS (EI) m/z: 287 (4, M − CH ), 285 (1, M
−
3
3
2
3
δ 14.1 (C-14), 19.7, 21.7, 22.0, 22.8, 22.9, 25.49, 27.54, 27.5, 29.6,
OH), 269 (2), 227 (33), 209 (16), 191 (8), 169 (8), 151 (5), 141 (5),
135 (13), 129 (1), 121 (17), 115 (12), 109 (23), 101 (5), 100 (10), 95
(25), 87 (4), 85 (73), 79 (21), 73 (6), 69 (50), 67 (39), 59 (58), 57
(52), 55 (54), 45 (7), 43 (100), 41 (58). HRMS (ESI) m/z: [M +
3
0.8, 30.9, 31.0, 31.3, 31.4, 33.4, 33.5, 33.7, 33.8, 62.5 (C-6′), 67.45
(
C-1), 67.51 (C-1), 70.77 (ROCH Ph), 70.85 (ROCH Ph), 74.50,
2
2
7
4.53 (br), 74.57, 74.59, 78.9 (C-10), 79.0 (C-10), 98.98 (C-2′), 99.00
+
•
(
(
C-2′), 127.41 (Ar CH), 127.44 (Ar CH), 127.76 (2 × Ar CH), 127.80
Na] calcd for C H NaO : 325.2355, found 325.2352. Anal. Calcd
17 34 4
2 × Ar CH), 128.29 (2 × Ar CH), 128.30 (2 × Ar CH), 139.0 (Ar C),
for C H O : C, 67.51; H, 11.33. Found: C, 67.25; H, 11.23.
17
34
4
1
2
39.1 ppm (Ar C). GC/MS (EI) m/z: 351 (0.1), 281 (0.1), 249 (2),
45 (5), 227 (11), 209 (4), 191 (2), 187 (4), 177 (1), 169 (3), 157
4-((4,5-erythro)-2,2-Dimethyl-5-(4-oxooctyl)-1,3-dioxolan-4-yl)-
butanoic acid (erythro-31). Diol erythro-30 (305 mg, 1.01 mmol) was
oxidized with PDC (98%, 2.18 g, 5.68 mmol) in DMF (12 mL) under
an Ar atmosphere over 20 h, as described for the synthesis of (S,S)-31.
Purification by flash column chromatography (silica gel, 17% EtOAc in
petroleum spirits 40−60 to 100% EtOAc) afforded erythro-31 (283
(
(
(
1), 143 (1), 141 (12), 129 (1), 123 (5), 115 (1), 107 (4), 101 (3), 91
+
•
+•
97, C H7 ), 85 (100, THP ), 81 (7), 77 (5), 69 (7), 67 (14), 57
7
+
•
17), 55 (23), 43 (13), 41 (18). HRMS (ESI) m/z: [M + Na] calcd
for C H NaO : 459.3086, found 459.3086. Anal. Calcd for
2
6
44
5
1
C H O : C, 71.52; H, 10.16. Found: C, 71.20; H, 10.13.
mg, 0.90 mmol, 89%) as a pale yellow, viscous oil. H NMR (400
26
44
5
(
5,6-erythro)-10-(Benzyloxy)tetradecane-1,5,6-triol (erythro-38).
MHz, CDCl ): δ 0.88 (t, 3H, J = 7.3 Hz, CH -14), 1.22−1.91 (m,
3
3
A solution of erythro-37 (805 mg, 1.84 mmol) and p-TsOH.H O
100 mg, cat.) in MeOH (15 mL) was stirred at room temperature for
0 h. Solid NaHCO (400 mg) was added to quench the reaction and
the solvent was evaporated in vacuo. The residue was purified by flash
column chromatography (silica gel, 50% EtOAc in petroleum spirits
18H, incl. 1.30 [s, 3H, ketal CH ], 1.40 [s, 3H, ketal CH ]), 2.33−2.46
2
3
3
(
2
(m, 6H, CH -2, CH -9 and CH -11), 4.01 ppm (m, 2H, CH-5 and
2 2 2
CH-6). 13C NMR (100 MHz, CDCl ): δ 13.8 (C-14), 20.6, 21.5, 22.4,
3
3
25.91 (ketal CH ), 25.95, 28.5 (ketal CH ), 29.0, 29.1, 33.6, 42.4, 42.5,
3
3
77.5, 77.7, 107.7 (ketal C(CH ) ), 178.6 (br, C-1), 211.1 ppm (C-10).
3 2
+•
+•
4
1
0−60 to 100% EtOAc) to afford the racemic triol erythro-38 (650 mg,
GC/MS (EI) m/z: 314 (0.02, M ), 299 (0.1, M − CH ), 221 (1),
140 (1), 137 (3), 127 (1), 119 (1), 113 (1), 100 (2), 99 (1), 87 (3), 85
3
1
.84 mmol, quantitative) as a cream-colored solid. Mp: 56−58 °C. H
+•
+•
+•
NMR (400 MHz, CDCl ): δ 0.88 (t, 3H, J = 6.9 Hz, CH -14), 1.21−
(13, C H O ), 73 (1), 59 (13, C H O ), 57 (33, C H ), 45 (14),
3
3
5 9 2 3 2 4 9
+•
1
1
.67 (m, 18H), 1.80 (br, 2H, 2 × ROH), 2.29 (br, 1H, ROH), 3.37 (m,
43 (100). HRMS (ESI) m/z: [M + Na] calcd for C H NaO :
17 30 5
H, CH-10), 3.55 (m, 2H, CH-5 and CH-6), 3.62 (t, 2H, J = 5.6 Hz,
CH -1), 4.48 (m, 2H, ROCH Ph), 7.21−7.37 ppm (m, 5H, Ar-H).
NMR (100 MHz, CDCl ): (mixture of diastereomers) δ 14.1 (C-14),
1.7, 21.9, 22.2, 22.9, 27.47, 27.52, 30.67, 30.70, 31.3, 31.4, 32.4, 33.4,
3.5, 33.7, 33.8, 62.6 (C-1), 70.75 (ROCH Ph), 70.84 (ROCH Ph),
4.5 (br), 74.6, 78.9 (C-10), 79.1 (C-10), 127.4 (Ar CH), 127.5 (Ar
337.1991, found 337.1997. Anal. Calcd for C H O : C, 64.94; H,
17 30 5
13
C
9.62. Found: C, 64.97; H, 9.55.
2
2
3
Methyl 4-((4,5-erythro)-2,2-dimethyl-5-(4-oxooctyl)-1,3-dioxolan-
4-yl)butanoate (erythro-32). Ketoacid erythro-31 (45 mg, 0.14 mmol)
was esterified with ethereal CH N in a mixture of MeOH (2 mL) and
2
3
7
2
2
2
2
Et O (1 mL) at 0 °C, as described for the synthesis of (S,S)-32.
2
CH), 127.78 (2 × Ar CH), 127.84 (2 × Ar CH), 128.30 (2 × Ar CH),
28.31 (2 × Ar CH), 138.9 (Ar C), 139.0 ppm (Ar C). GC/MS (EI)
m/z: 249 (0.4), 243 (0.3), 228 (1), 207 (1), 187 (1), 177 (1), 169 (2),
41 (8), 133 (1), 130 (4), 123 (5), 107 (4), 103 (2), 91 (100,
Purification by flash column chromatography (silica gel, 25% to 33%
EtOAc in petroleum spirits 40−60 to 100% EtOAc) afforded erythro-
1
1
32 (47 mg, 0.14 mmol, quantitative) as a colorless oil. H NMR (400
1
MHz, CDCl ): δ 0.88 (t, 3H, J = 7.3 Hz, CH -14), 1.20−1.90 (m,
3
3
+•
C H ), 85 (11), 81 (7), 77 (4), 73 (1), 67 (8), 59 (1), 57 (11), 55
18H, incl. 1.30 [s, 3H, ketal CH ], 1.39 [s, 3H, ketal CH ]), 2.28−2.46
7
7
3
3
+•
(
10), 45 (1), 43 (8), 41 (10). HRMS (ESI) m/z: [M + Na] calcd for
(m, 6H, CH -2, CH -9 and CH -11), 3.65 (s, 3H, RCO CH ), 4.00
2 2 2 2 3
13
C H NaO : 375.2511, found 375.2511. Anal. Calcd for C H O : C,
ppm (m, 2H, CH-5 and CH-6). C NMR (100 MHz, CDCl ): δ 13.8
21
36
4
21 36
4
3
7
1.55; H, 10.29. Found: C, 71.49; H, 10.21.
5,6-erythro)-1,5,6,10-Tetradecanetetraol (erythro-29). A mixture
of erythro-38 (580 mg, 1.65 mmol) and Pd/C (10%, 61 mg) in MeOH
20 mL) was degassed-purged twice with N (g) and then twice with
(C-14), 20.6, 21.7, 22.4, 25.9 (2C, incl. one × ketal CH ), 28.6 (ketal
3
(
CH ), 29.1 (2C), 33.8, 42.4, 42.5, 51.5 (RCO CH ), 77.5, 77.7, 107.6
3
2
3
(ketal C(CH ) ), 173.9 (C-1), 211.0 ppm (C-10). GC/MS (EI) m/z:
3
2
+•
+•
(
328 (0.2, M ), 313 (17, M − CH ), 271 (1), 254 (3), 253 (18), 239
(16), 221 (18), 210 (1), 203 (3), 193 (2), 185 (1), 181 (4), 175 (5),
169 (5), 155 (3), 140 (11), 137 (19), 129 (10), 127 (4), 115 (17), 113
(7), 101 (3), 99 (6), 98 (13), 93 (14), 87 (2, C H O ), 85 (100,
C H O ), 74 (3), 73 (4), 71 (10), 59 (18, C H O ), 57 (47,
2
3
H (g). The reaction mixture was stirred under a H atmosphere at
2
2
room temperature for 20 h and then was filtered through a pad of
Celite that was washed thoroughly with additional MeOH. The solvent
was evaporated in vacuo and the residue was purified by flash column
chromatography (silica gel, 5% to 9% MeOH in CH Cl ) to afford
+
•
4
7
2
+•
+•
5
9
2
3
2
+
•
+•
2
2
C H ), 55 (35), 43 (56). HRMS (ESI) m/z: [M + Na] calcd for
4
9
racemic erythro-29 (420 mg, 1.60 mmol, 97%) as a white solid. Mp:
C H NaO : 351.2147, found 351.2145. Anal. Calcd for C H O : C,
18 32 5 18 32 5
1
1
10−112 °C. H NMR (400 MHz, CD OD): δ 0.91 (t, 3H, J = 7.1
65.82; H, 9.82. Found: C, 65.71; H, 9.64.
Methyl 4-((4,5-erythro)-2,2-dimethyl-5-(4-hydroxyoctyl)-1,3-diox-
olan-4-yl)butanoate (erythro-33). Ketoester erythro-32 (40 mg, 0.12
3
Hz, CH -14), 1.24−1.77 (m, 18H), 3.36 (m, 2H, CH-5 and CH-6),
3
13
3.52 (m, 1H, CH-10), 3.56 ppm (t, 2H, J = 6.4 Hz, CH -1). C NMR
2
P
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
+
•
+•
mmol) was reduced with NaBH (10 mg, 0.26 mmol) in a mixture of
z: 318 (0.1, M ), 303 (19, M − CH ), 301 (1), 243 (8), 225 (9),
4
3
MeOH (3 mL) and Et O (1 mL) over 2 h, as described for the
201 (1), 197 (1), 187 (1), 183 (6), 173 (4), 158 (5), 139 (16), 131
(2), 121 (10), 117 (2), 103 (1), 100 (17), 93 (9), 87 (51, C H D O
and/or C H O ), 79 (7), 73 (5), 71 (6), 59 (55, C H D and/or
4 7 2 4 7 2
2
+•
synthesis of (S,S)-33. Purification by flash column chromatography
5 7 2
+
•
+•
(
silica gel, 17% to 66% Et O in petroleum spirits 40−60) afforded
2
1
+•
erythro-33 (38 mg, 0.11 mmol, 94%) as a viscous, pale yellow oil. H
NMR (500 MHz, C D ): δ 0.92 (t, 3H, J = 7.0 Hz, CH -14), 1.16−
1
C H O ), 55 (27), 45 (16), 43 (100).
2 3 2
2
The crude [ H ]-erythro-31 was then esterified with CH N in a
6
6
3
4
2
2
.82 (m, 21H, incl. 1.35 [s, 3H, ketal CH ], 1.489 and 1.492 [2 ×
mixture of MeOH (2 mL) and Et O (1 mL). Purification by flash
column chromatography (silica gel, 25% to 66% Et O in petroleum
spirits 40−60) afforded a colorless oil that contained [ H ]-erythro-32
(116 mg, 0.35 mmol, 91% over 2 steps, ≤1% [ H
3
2
overlapping s, 3H, ketal CH ]), 1.92 (m, 1H), 2.20 (ABX system, 2H,
3
2
2
2
JAB = 16.0, JAX = 7.2, JBX = 7.2 Hz, CH -2), 3.369 and 3.370 (2 ×
2
4
2
overlapping s, 3H, RCO CH ), 3.44 (m, 1H, CH-10), 3.90 ppm (m,
0
]) as the major
): δ 0.87 (t,
-14), 1.19−1.87 (m, 18H, incl. 1.29 [s, 3H, ketal
2
3
1
3
1
2
H, CH-5 and CH-6). C NMR (125 MHz, C D ): (mixture of
deuterium-labeled product. H NMR (500 MHz, CDCl
3H, J = 7.3 Hz, CH
CH ], 1.39 [s, 3H, ketal CH
system, 2H, JAB = 16.0, JAX = 7.4, JBX = 7.3 Hz, CH
hydrogen from CH or CHD at C-9 and/or C-11 of [ H
analogues), 3.64 (s, 3H, RCO CH
CH-6). C NMR (125 MHz, CDCl
25.8, 25.9 (ketal CH ), 28.5 (ketal CH
(m, incl. 42.6 [quintet, JC,D = 19.0 Hz, CD
Hz, CD ], C-9 and C-11), 51.5 (RCO CH
C(CH ), 173.9 (C-1), 211.3 ppm (C-10). GC/MS (EI) m/z: 332
(0.1, M ), 317 (17, M − CH ), 275 (1), 258 (3), 257 (17), 243
(16), 225 (13), 215 (1), 207 (2), 197 (3), 187 (2), 183 (6), 179 (4),
173 (5), 155 (3), 144 (13), 140 (17), 131 (4), 129 (15), 117 (2), 115
(21), 103 (1), 102 (5), 101 (10), 93 (12), 87 (100, C H D O and/
or C H O ), 74 (5), 73 (8), 71 (10), 59 (67, C H D and/or
3
6
6
diastereomers) δ 14.3 (C-14), 22.2, 22.9, 23.1, 23.2, 26.0 (ketal CH3),
3
2
2
7
1
6.1 (ketal CH ), 28.2, 28.81 (ketal CH ), 28.82 (ketal CH ), 29.56,
3
3
]), 2.28−2.43 (m, 2.1H, incl. 2.34 [ABX
2
3
3
3
9.58, 30.08, 30.15, 33.8, 37.74, 37.76, 37.81, 37.9, 50.9 (RCO CH ),
2
-2] + residual
2
3
2
2
1.4 (C-10), 71.5 (C-10), 77.8, 78.08, 78.11, 107.5 (ketal C(CH ) ),
2
0
]-[ H
3
]-
3
2
+
•
73.26 (C-1), 173.29 ppm (C-1). GC/MS (EI) m/z: 315 (4, M
3
−
2
3
), 4.00 ppm (m, 2H, CH-5 and
): δ 13.8 (C-14), 20.4, 21.7, 22.3,
), 29.0, 29.1, 33.8, 41.2−42.2
], 42.8 [quintet, JC,D = 18.9
), 77.5, 77.7, 107.6 (ketal
+
•
13
CH ), 313 (4, M − OH), 256 (9), 255 (53), 237 (11), 223 (37), 215
3
(
(
8
4), 205 (22), 197 (7), 187 (18), 177 (23), 163 (19), 157 (5), 137
20), 129 (9), 121 (34), 115 (36), 109 (28), 101 (8), 95 (35), 87 (7),
5 (66), 81 (33), 74 (8), 73 (11), 69 (37), 59 (45, C H O ), 57 (38,
3
3
2
+
•
2
3
2
2
2
3
+•
+•
C H ), 55 (64), 43 (100). HRMS (ESI) m/z: [M + Na] calcd for
3 2
)
4
9
+
•
+•
C H NaO : 353.2304, found 353.2294. Anal. Calcd for C H O : C,
3
18
34
5
18 34
5
6
5.42; H, 10.37. Found: C, 65.49; H, 10.50.
5,6-erythro)-6-(1,5-Dihydroxynonyl)-tetrahydropyran-2-one (er-
ythro-8) and Methyl (5,6-erythro)-5,6,10-trihydroxytetradecanoate
erythro-9). As described for the synthesis of (S,S)-8/9 from (S,S)-33,
(
+
•
5
7
2
+•
+•
(
4
7
2
4
7
2
+
•
+•
acid-catalyzed ketal methanolysis of erythro-33 (27.7 mg, 83.8 μmol)
C H O ), 55 (27), 43 (72). HRMS (ESI) m/z: [M + Na] calcd for
2
3
2
and treatment with CH N afforded a mixture of dihydroxylactone
C H D NaO : 355.2399, found 355.2398.
2
2
18 28
4
5
2
2
erythro-8 and trihydroxyester erythro-9 (23.0 mg, 79.2 μmol, 94%
Methyl 4-((4,5-erythro)-2,2-dimethyl-5-([3- H ,5- H ]-4-hy-
droxyoctyl)-1,3-dioxolan-4-yl)butanoate ([ H ]-erythro-33). Ke-
toester [ H ]-erythro-32 (76 mg, 0.23 mmol) was reduced with
NaBH (18 mg, 0.48 mmol) in a mixture of MeOH (3 mL) and Et O
(1 mL) over 2 h, as described for the synthesis of (S,S)-33. Purification
by flash column chromatography (silica gel, 17% to 66% Et O in
0;1;2
0;1;2
1
2
assuming all the product was erythro-9) as a white solid. H NMR (500
4
2
MHz, CDCl ): δ 0.87 (t, 3H, J = 7.0 Hz, CH -14), 1.20−2.66 (m,
3
3
4
∼
19H, incl. 2.34 [apparent t, 1.6H, J = 7.2 Hz, CH -2]), 3.33−3.44
2
4
2
(
m, 3.3H, incl. 3.39 [t, J = 5.8 Hz]), 3.52−3.62 (m, 5H, incl. 3.39 [t, J
13
=
6.0 Hz]), 3.64 ppm (s, 2.6H, RCO CH of ester erythro-9).
C
2
3
2
NMR (125 MHz, CDCl ): (mixture of diastereomers; appears to
contain mostly (5,6-erythro)-5,6,10-trihydroxytetradecanoic acid (er-
ythro-34); * denotes major signals) δ 14.0* (C-14), 18.2, 21.1, 21.2*,
petroleum spirits 40−60) afforded a viscous, pale yellow oil that
3
2
2
contained [ H ]-erythro-33 (74 mg, 0.22 mmol, 97%, ≤1% [ H ]) as
4
0
1
the major deuterium-labeled product. H NMR (500 MHz, C D ): δ
6
6
2
2
3
3
6
7
7
1.3*, 21.88*, 21.95, 22.7, 26.17, 26.22*, 26.4, 26.6*, 26.8, 27.8* (br),
8.6, 29.3, 29.6*, 29.7, 30.0*, 30.19, 30.24*, 30.58*, 30.62*, 30.79*,
1.3*, 31.5, 31.7*, 31.9, 33.7* (br), 34.2, 36.7, 36.8*, 36.9, 37.0, 37.1*,
7.2*, 37.3*, 51.4 (RCO CH of ester erythro-9), 58.4, 58.5*, 60.0,
2.5*, 62.6, 65.5, 67.6, 67.7, 70.5 (br), 70.7, 70.8, 71.1, 71.3, 71.40*,
1.43, 71.5, 71.6, 71.7*, 72.1, 72.2, 72.4, 72.45, 72.53, 72.7*, 74.08*,
4.14*, 74.3*, 74.5*, 82.9, 83.0, 83.5, 83.6, 172.1 (C-1 of lactone
0.92 (t, 3H, J = 7.0 Hz, CH -14), 1.15−1.81 (m, 17H, incl. 1.35 [s, 3H,
3
ketal CH ], 1.492 and 1.494 [2 × overlapping s, 3H, ketal CH ]), 1.93
3
3
(m, 1H), 2.20 (ABX system, 2H, J = 16.1, JAX = 7.5, JBX = 7.2 Hz,
2
AB
CH -2), 3.367 and 3.368 (2 × overlapping s, 3H, RCO CH ), 3.41 (m,
2
3
2
2
3
1
3
1H, CH-10), 3.90 ppm (m, 2H, CH-5 and CH-6). C NMR (125
MHz, C D ): (mixture of diastereomers) δ 14.3 (C-14), 22.2, 22.7,
6
6
22.9, 23.1, 26.04 (ketal CH
CH ), 29.56, 29.58, 30.0, 30.1, 33.8, 36.4−37.5 (m, C-9 and C-11),
50.9 (RCO CH ), 71.1 (C-10), 71.3 (C-10), 77.8, 78.09, 78.11, 107.5
(ketal C(CH ), 173.25 (C-1), 173.28 ppm (C-1). GC/MS (EI) m/z:
), 26.06 (ketal CH ), 28.0, 28.8 (br, ketal
3
3
erythro-8), 173.9 (C-1 of ester erythro-9), 174.32* and 174.33* ppm
3
(
8
(
(
6
C-1 of acid erythro-34). GC/MS (EI) m/z: (dihydroxylactone erythro-
) 241 (0.4, M − OH), 183 (32), 165 (23), 159 (3), 157 (4), 154
1), 143 (1), 141 (67), 137 (22), 129 (12), 123 (80), 119 (36), 115
2
3
+
•
)
3 2
+
•
+•
319 (3, M − CH ), 317 (5, M − OH), 260 (5), 259 (33), 245 (2),
240 (5), 229 (1), 227 (18), 215 (1), 208 (10), 199 (4), 190 (7), 180
(11), 167 (13), 157 (5), 143 (22), 139 (12), 133 (2), 131 (13), 121
3
3), 111 (12), 101 (12), 100 (100), 99 (42), 87 (7), 81 (81), 71 (53),
+
•
7 (50), 57 (50, C H9 ), 55 (82), 43 (57), 41 (53). HRMS (ESI) m/
4
+
•
z: erythro-8: [M + Na] calcd for C H NaO : 281.1729, found
2
(13), 115 (34), 111 (17), 105 (2), 101 (10), 95 (13), 89 (3), 87 (53),
14
26
4
+•
+•
81.1729; erythro-9: [M + Na] calcd for C H NaO : 313.1991,
83 (24), 74 (9), 73 (13), 71 (34), 59 (65, C
4
H
7
D
2
and/or
15
30
5
+•
+•
found 313.1986.
C
2
H
3
O
2
), 55 (41), 43 (100). HRMS (ESI) m/z: [M + Na] calcd
NaO : 357.2555, found 357.2549.
(5,6-erythro)-6-([4- H ,6- H ]-1,5-Dihydroxynonyl)-tetrahy-
Sodium (5,6-erythro)-5,6,10-trihydroxytetradecanoate (erythro-
for C18
H
30
D
4
5
2
2
3
5). A small amount of the erythro-8/9/34 mixture was treated with
0
;1;2
0;1;2
1
2
2
2
NaOD in D O and analyzed by NMR. H NMR (400 MHz, D O/1,4-
dropyran-2-one ([ H
(
]-erythro-8) and Methyl [9- H0;1;2,11- H0;1;2]-
4
2
2
2
5,6-erythro)-5,6,10-trihydroxytetradecanoate ([ H ]-erythro-9).
dioxane) δ 0.87 (t, 3H, J = 7.0 Hz, CH -14), 1.23−1.78 (m, 18H), 2.20
4
3
Following the procedure described for the synthesis of (S,S)-8/9
(
(
ABX system, 2H, J = 14.7, J = 7.2, J = 7.2 Hz, CH -2), 3.56
m, 2H, CH-5 and CH-6), 3.67 ppm (m, 1H, CH-10). C NMR (100
2 AB AX BX 2
2
13
from (S,S)-33, acid-catalyzed ketal methanolysis of [ H ]-erythro-33
4
(
31.7 mg, 94.8 μmol) and treatment with ethereal CH N afforded a
MHz, D O/1,4-dioxane): (mixture of diastereomers) δ 13.3 (C-14),
2 2
2
2
white solid that contained a mixture of dihydroxylactone [ H ]-erythro-
8
assuming all the product was [ H ]-erythro-9, ≤1% [ H ]) as the major
deuterium-labeled products. H NMR (750 MHz, CDCl ): δ 0.85 (2
2
3
1
1.1, 21.2, 22.0, 22.3, 26.9, 27.0, 30.85, 30.88, 30.91, 31.1, 35.5, 35.6,
5.7, 35.9, 37.4, 71.4 (C-10), 71.5 (C-10), 74.08 (br), 74.14, 74.2,
83.6 ppm (C-1).
4
2
and trihydroxyester [ H ]-erythro-9 (25.3 mg, 85.9 μmol, 91%
4
2
2
4
0
1
2
2
Methyl 4-((4,5-erythro)-2,2-dimethyl-5-([3- H ,5- H0;1;2]-4-ox-
3
0
;1;2
2
ooctyl)-1,3-dioxolan-4-yl)-butanoate ([ H ]-erythro-32). As de-
scribed for the synthesis of [ H ]-(S,S)-32, ketoacid erythro-31 (120
overlapping t, 3H, J = 7.0 Hz, CH
2.31 [m, 1.4H, CH -2]), 2.89 (br m, 3H), 3.32−3.42 (m, 2H, incl. 3.35
[t, J = 6.3 Hz]), 3.49−3.60 (m, 2.8H), 3.62 (s, 0.6H, RCO CH of
]-erythro-9), 4.04 ppm (t, 0.9H, J = 6.5 Hz, CH-5 of lactone
-14), 1.18−2.60 (m, ∼15H, incl.
3
4
2
4
2
mg, 0.38 mmol) was deuterated with NaOD/D O over 30 days to
2
3
2
2
2
2
provide [ H ]-erythro-31 (≤1% [ H ]) as the major product.
ester [ H
4
4
0
2
2
2
13
4
-((4,5-erythro)-2,2-Dimethyl-5-([3- H ,5- H0;1;2]-4-oxooctyl)-
[ H ]-erythro-8). C NMR (188 MHz, CDCl ): (mixture of
diastereomers; appears to contain mostly lactone [ H ]-erythro-8
4
3
0
;1;2
2
2
1
,3-dioxolan-4-yl)butanoic acid ([ H ]-erythro-31). GC/MS (EI) m/
4
4
Q
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
2
2
1
with some ester [ H ]-erythro-9 and [ H ]-(5,6-erythro)-5,6,10-
≥95% E isomer) as a colorless oil. H NMR (500 MHz, CDCl ): δ
4
4
3
2
trihydroxytetradecanoic acid ([ H ]-erythro-34); * denotes major
signals) δ 13.9 (C-14), 14.0* (C-14), 18.2*, 21.27, 21.28, 21.33,
1.37, 21.40, 21.45, 21.48*, 21.56*, 21.61*, 21.67*, 21.74, 22.4,
2.60*, 22.61*, 25.35*, 25.44, 26.0*, 26.16, 26.20*, 26.21*, 26.23,
6.25, 26.26, 26.28, 26.32, 26.34, 26.5*, 26.7*, 27.3*, 27.58* (br),
7.61* (br), 28.6 (br), 29.3, 29.6*, 29.7*, 29.9*, 30.1*, 30.2*, 30.6
0.87 (t, 3H, J = 6.7 Hz, CH -8), 1.22−1.34 (m, 7H, incl. 1.26 [t, 3H, J
= 7.1 Hz, RCO CH CH ]), 1.44 (m, 2H), 2.17 (qd, 1.90H, J = 7.3, 1.4
Hz, CH -4 of E isomer), 2.62 (qd, 0.10H, J = 7.5, 1.6 Hz, CH -4 of Z
isomer), 4.16 (2 overlapping q, 2H, J = 7.1 Hz, RCO
4
3
2
2
3
2
2
2
2
2
2
CH CH ), 5.73
2
2 3
(dt, 0.05H, J = 11.5, 1.7 Hz, CH-2 of Z isomer), 5.79 (dt, 0.95H, J =
15.7, 1.5 Hz, CH-2 of E isomer), 6.19 (dt, 0.05H, J = 11.5, 7.5 Hz, CH-
3 of Z isomer), 6.94 ppm (dt, 0.95H, J = 15.6, 7.0 Hz, CH-3 of E
(
br), 31.3 (br), 31.5*, 31.7*, 31.8, 32.0, 33.74*, 33.75*, 33.98*,
isomer). 13C NMR (125 MHz, CDCl
): δ 13.9 (CH
22.4, 27.7, 28.7 (Z isomer), 28.9 (Z isomer), 31.3, 31.5 (Z isomer),
32.1, 59.7 (RCO CH CH of Z isomer), 60.1 (RCO CH CH of E
), 14.3 (CH ),
3 3
3
5
7
7
7
4.00*, 34.1*, 34.1*, 34.4 (br), 35.5−36.7 (br m, C-9 and C-11),
0.4*, 51.4*, 58.40*, 58.44*, 58.5*, 62.47*, 62.52*, 64.1 (br), 70.1,
0.41, 70.42, 70.45, 70.54, 70.6*, 70.7*, 71.11, 71.15, 71.19*, 71.22,
1.3, 71.4*, 71.5 (br), 72.0, 72.1* (br), 72.2*, 72.4*, 72.5 (br), 72.7*,
3
2
2
3
2
2
3
isomer), 119.6 (C-2 of Z isomer), 121.2 (C-2 of E isomer), 149.5 (C-3
of E isomer), 150.6 (C-3 of Z isomer), 166.8 ppm (C-1). GC/MS (EI)
3.7−73.8 (br), 74.05, 74.11, 74.3, 74.5, 82.9, 83.0, 83.49* and 83.53*
2
+•
+•
(
C-5 of lactone [ H ]-erythro-8), 83.6, 83.7, 172.0* (C-1 of lactone
m/z: (E isomer) 170 (1, M ), 155 (1, M − CH ), 142 (1), 141 (3,
3
4
2
2
+•
+•
+•
+•
[
H ]-erythro-8), 173.88 and 173.90 (C-1 of ester [ H ]-erythro-9),
74.26 and 174.28 ppm (C-1 of acid [ H ]-erythro-34). GC/MS (EI)
m/z: (dihydroxylactone [ H ]-erythro-8) 244 (0.1, M − H O), 241
2), 226 (0.4), 218 (1), 207 (1), 199 (1), 193 (1), 185 (25), 174 (1),
67 (11), 163 (3), 157 (2), 156 (8), 145 (59), 143 (3), 138 (21), 133
1), 129 (11), 126 (57), 121 (25), 119 (4), 111 (15), 105 (2), 101
43), 100 (95), 99 (52), 89 (6), 83 (57), 73 (24), 71 (92), 59 (37,
C H D ), 57 (68), 55 (83), 43 (100), 41 (65). HRMS (ESI) m/z:
H ]-erythro-8: [M + Na] calcd for C H D NaO : 285.1980,
M − Et), 127 (10, M − Pr), 125 (32, M − OEt), 124 (15, M −
+•
4
4
2
1
EtOH), 101 (26), 99 (27, M − C
H11), 96 (22), 88 (15), 86 (14),
5
4
2
+•
82 (20), 81 (14), 73 (38), 71 (5), 68 (25), 57 (14), 55 (100), 43 (28),
4
2
+
•
+•
4
1 (69). GC/MS (EI) m/z: (Z isomer) 170 (15, M ), 155 (1, M −
+•
(
1
(
+
•
+•
CH ), 142 (3), 141 (3, M − Et), 127 (67, M − Pr), 125 (30, M
3
+
•
+•
−
(
(
OEt), 124 (4, M − EtOH), 101 (9), 99 (100, M − C H ), 96
5
11
12), 88 (12), 86 (20), 82 (24), 81 (29), 73 (24), 71 (13), 68 (34), 57
(
13), 55 (92), 43 (56), 41 (94). HRMS (ESI) m/z: [M + Na]+ calcd
•
+
•
4
7
2
2
+•
for C H NaO : 193.1204, found 193.1207.
[
10 18
2
4
14 22
4
4
2
2
2
2
+•
Ethyl [2- H ,3- H ]octanoate ([ H ]-41). A mixture of (E)-40
found 285.1984; [ H ]-erythro-9: [M + Na]
C H D NaO : 317.2242, found 317.2255.
calcd for
0;1;2 0;1;2 2
4
(
5.00 g, 29.4 mmol) and Pd/C (5%, 25 mg) in EtOH (200 mL) was
degassed-purged twice with N (g) and then twice with H (g). The
reaction mixture was stirred under a
atmosphere at room temperature for 4 h and then was filtered through
a pad of Celite that was washed thoroughly with Et O (3 × 50 mL).
The solvent was removed in vacuo to afford a colorless oil that
contained [ H ]-41 (5.12 g, 29.4 mmol, quantitative, ∼20% [ H ]) as
the predominant deuterium-labeled product. H NMR (300 MHz,
15
26
4
5
2
Synthesis of Compounds with Dioxygenated Chains. Methyl
2
2
2
2
2
2
[
9- H ,11- H ]-6,10-dihydroxytetradecanoate ([ H ]-10) and
H
2
(D
2
, 99.7 atom % D)
0
;1;2
0;1;2
4
2
2
2
methyl [9- H ,11- H ]-5,10-dihydroxytetradecanoate ([ H ]-
0
;1;2
0;1;2
4
1
2
1). Following the procedure described for the synthesis of alcohol
2
2
2, alkene [ H ]-(E)-27 (60 mg, 0.23 mmol) was hydroborated using
borane-dimethylsulfide complex (2.0 M in THF, 0.12 mL, 0.24 mmol)
4
2
2
2
0
1
in anhydrous CH Cl (5 mL) under a N atmosphere over 2 h, and
2
2
2
then was oxidized using aqueous NaOH solution (20%, 2.0 mL, 10.00
CDCl ): δ 0.86 (t, 3H, J = 6.8 Hz, CH -8), 1.18−1.45 (m, 11H, incl.
3
3
mmol) and H O (30%, 2.0 mL, 17.64 mmol). Purification by flash
1.23 [t, 3H, J = 7.1 Hz, RO CH CH ]), 1.59 (m, 1.5H, CHD-3 of
2
2
2 2 3
2
2
2
2
column chromatography (silica gel, 20% EtOAc in n-hexane) afforded
[2,3- H ]-41 and [3- H ] or [2,2,3- H ]-analogues + CH -3 of [ H ],
2 1 3 2 0
[2- H ], or [2,2- H ]-analogues), 2.26 (br t, 1.7H, J = 7.5 Hz, CHD-2
of [2,3- H ]-41 and [2- H ] or [2,3,3- H ]-analogues + CH -2 of
2 1 3 2
[ H ], [3- H ], or [3,3- H ]-analogues), 4.10 ppm (q, 2H, J = 7.1 Hz,
2
2
2
an isomeric mixture enriched in the 6,10-dihydroxyester [ H ]-10 (18
4
1 2
2
2
2
2
2
2
mg, 64.7 μmol, 28%, ∼9:1 [ H ]-10:[ H ]-11, ≤1% [ H ]) and a
4
4
0
2
2
2
2
mixture enriched in the 5,10-dihydroxyester [ H ]-11 (12 mg, 43.1
4
0 1 2
CH
2
2
2
13
μmol, 19%, ∼9:1 [ H ]-11:[ H ]-10, ≤1% [ H ]) as colorless oils.
RO
(CH
(m), 29.1, 31.6 (br), 34.2−34.4 (m), 60.1 (RO CH CH ), 173.9 ppm
2
2
CH ). C NMR (75 MHz, CDCl ): δ 14.0 (CH ), 14.2
3
3
3
4
4
0
2
2
2
Methyl [9- H ,11- H ]-6,10-dihydroxytetradecanoate ([ H ]-
3
), 22.6, 24.9, 25.0 (minor singlet from isotope shift), 28.7−29.0
0
;1;2
0;1;2
4
1
1
0). H NMR (400 MHz, C D ): δ 0.93 (t, 3H, J = 7.0 Hz, CH -14),
6
6
3
2
2
3
+
•
+•
1
.20−1.67 (m, 14H), 2.15 (t, 2H, J = 7.3 Hz, CH -2), 3.36−3.46 ppm
(C-1). GC/MS (EI) m/z: 174 (1, M ), 143 (2), 129 (27, M
−
2
13
(
(
m, 5H, incl. 3.38 [s, 3H, RCO CH ]). C NMR (100 MHz, C D ):
Mixture of diastereomers; signals for C-9 and C-11 not observed) δ
OEt), 115 (5), 101 (22), 88 (100), 70 (40), 61 (63), 43 (53). HRMS
2 3 6 6
+
•
(ESI) m/z: [M + Na] calcd for C H D NaO : 197.1487, found
10 18 2 2
1
3
1
2
4.3 (C-14), 21.8, 21.9, 23.1, 25.2, 25.49, 25.51, 28.1, 34.0, 37.5, 37.58,
197.1497.
[2- H0;1;2,3-2H0;1;2]-1-Octanol ([ H ]-42). A solution of ester [ H ]-
2
2
2
7.60, 37.8, 50.9 (RCO CH ), 71.1, 71.21, 71.24, 71.3, 173.5 ppm (C-
2
3
2
2
+
•
). GC/MS (EI) m/z: 278 (0.2, M ), 261 (0.3), 228 (0.2), 210 (2),
41 (4.00 g, 23.0 mmol) in anhydrous Et O (20 mL) was added
dropwise to a solution of LiAlH4 (95%, 1.74 g, 43.6 mmol) in
anhydrous Et O (100 mL) with stirring under a N atmosphere at 0
°C. The reaction mixture was allowed to warm to room temperature
and stirred for 2 h. Sodium sulfate decahydrate (20 g) was added to
quench the reaction. The mixture was stirred until it was white in color
and then filtered through a pad of Celite that was washed thoroughly
2
01 (3), 183 (8), 169 (13), 151 (17), 145 (76), 126 (30), 113 (71), 87
(
78), 71 (59), 67 (61), 59 (72), 57 (99), 55 (100), 43 (92), 41 (80).
2
2
+•
HRMS (ESI) m/z: [M + Na] calcd for C H D NaO : 301.2293,
found 301.2295.
15
26
4
4
Methyl [9- H ;1;2,11-2H0;1;2]-5,10-dihydroxytetradecanoate ([ H ]-
2
2
0
4
1
1
1). H NMR (400 MHz, C D ): δ 0.93 (t, 3H, J = 7.0 Hz, CH -14),
6
6
3
1
.20−1.81 (m, 14H), 2.15 (t, 2H, J = 7.3 Hz, CH -2), 3.32−3.44 ppm
with Et O (3 × 50 mL). The filtrate was concentrated in vacuo to
2
2
13
2
(
(
m, 5H, incl. 3.37 [s, 3H, RCO CH ]). C NMR (100 MHz, C D ):
Mixture of diastereomers; signals for C-9 and C-11 not observed) δ
afford a colorless oil that contained the alcohol [ H ]-42 (3.00 g, 22.7
2
3
6
6
2
2
mmol, 99%, ∼20% [ H ]) as the predominant deuterium-labeled
product. H NMR (300 MHz, CDCl ): δ 0.86 (t, 3H, J = 6.7 Hz, CH -
0
1
1
5
4.3 (C-14), 21.4, 23.1, 25.8, 25.9, 26.0, 28.0, 33.9, 37.2, 37.86, 37.88,
1.0 (RCO CH ), 70.9, 71.0, 71.2, 71.3, 173.6 ppm (C-1). GC/MS
3
3
2
8), 1.18−1.36 (m, 9.6H, incl. ∼1.6H for CHD-3 of [2,3- H ]-42 and
2
3
2
2 2 2 2
(
1
EI) m/z: 228 (0.1), 187 (6), 169 (22), 151 (13), 132 (5), 123 (26),
22 (33), 100 (7), 99 (46), 95 (15), 71 (100), 55 (72), 42 (74).
[3- H ] or [2,2,3- H ]-analogues + CH -3 of [ H ], [2- H ], or
1 3 2 0 1
2
2
[2,2- H ]-analogues), 1.54 (m, 1.6H, CHD-2 of [2,3- H ]-42 and
2 2
+•
2
2
2
2
HRMS (ESI): [M + Na] calcd for C H D NaO : 301.2293, found
3
[2- H ] or [2,3,3- H ]-analogues + CH -2 of [ H ], [3- H ], or
15
26
4
4
1 3 2 0 1
2
01.2296.
[3,3- H
6.6 Hz, CH
(br m, C-3), 29.2−29.4 (br m), 31.8, 32.6−32.9 (m, C-2), 63.1 ppm
2
]-analogues), 1.78 (br s, 1H, ROH), 3.61 ppm (br t, 2H, J =
2
2
13
Synthesis of Hydroxylactones [ H ]-(S,S)-12 and [ H ]-(R,R)-
2. Ethyl (E)-2-octenoate [(E)-40]. A solution of hexanal (98%, 0.26
-1). C NMR (75 MHz, CDCl ): δ 14.1 (C-8), 22.6, 25.5
2 3
2
2
1
+
•
+•
mL, 2.06 mmol) and ethyl 2-(triphenylphosphoranylidene)acetate
(br, C-1). GC/MS (EI) m/z: 115 (0.2, M − OH), 114 (0.4, M
−
(
39)23 (1.02 g, 2.93 mmol) in anhydrous CH Cl (20 mL) was heated
H O), 98 (1), 84 (32), 70 (77), 56 (100), 43 (87), 42 (88), 41 (90).
2
2
2
2
2
2
at reflux under a N atmosphere for 20 h. The reaction mixture was
cooled to room temperature and concentrated in vacuo, and the
[2- H ,3- H ]-1-Iodooctane ([ H ]-43). Following the proce-
2
0;1;2
0;1;2
2
2
dure described for the synthesis of iodide 19, alcohol [ H ]-42 (380
2
residue was purified by flash column chromatography (silica gel, 2% to
mg, 2.87 mmol) was iodinated using I (99%, 950 mg, 3.71 mmol),
2
5% EtOAc in n-hexane) to afford (E)-40 (322 mg, 1.89 mmol, 92%,
PPh (99%, 980 mg, 3.70 mmol), and imidazole (390 mg, 5.73 mmol)
3
R
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
in a mixture of anhydrous Et O (7.5 mL) and CH CN (2.5 mL) at 0
GC/MS (EI) m/z: 198 (2), 155 (1), 138 (2), 125 (4), 110 (8), 96
2
3
°
C under a N atmosphere over 2 h. Purification by flash column
(33), 82 (82), 67 (100), 55 (77).
2
Methyl [8- H0;1;2,9- H0;1;2]-(E)-5-tetradecenoate ([2H
2
2
]-(E)-47). Al-
chromatography (silica gel, 20% EtOAc in n-hexane) afforded a pale
pink oil that contained iodide [ H ]-43 (460 mg, 1.90 mmol, 66%,
2
2
2
cohol [ H
]-(E)-46 (200 mg, 0.93 mmol) was oxidized with Jones’
2
2
2
1
∼
20% [ H ]) as the predominant deuterium-labeled product.
H
reagent (8 N) in acetone (4 mL) at 0 °C following the procedure
described for the synthesis of (E)-25. The crude acid obtained was
then esterified with ethereal CH N in MeOH (5 mL) at 0 °C, as
2 2
described for the synthesis of (S,S)-32. Purification by flash column
0
NMR (300 MHz, CDCl ): δ 0.86 (t, 3H, J = 6.9 Hz, CH -8), 1.18−
3
3
2
2
1
.40 (m, 9.5H, incl. ∼1.5H for CHD-3 of [2,3- H ]-43 and [3- H ] or
2
1
2
2
2
2
[
2,2,3- H ]-analogues + CH -3 of [ H ], [2- H ], or [2,2- H ]-
3
2
0
1
2
2
analogues), 1.79 (br q, 1.6H, J = 7.1 Hz, CHD-2 of [2,3- H ]-43
and [2- H ] or [2,3,3- H ]-analogues + CH -2 of [ H ], [3- H ] or
chromatography (silica gel, 10% EtOAc in n-hexane) afforded a
2
2
2
2
2
2
colorless oil that contained [ H
]-(E)-47 (100 mg, 0.41 mmol, 44%
1
3
2
0
1
2
2
13
2
[
(
(
3,3- H ]-analogues), 3.16 ppm (t, 2H, J = 6.8 Hz, CH -1). C NMR
75 MHz, CDCl ): δ 7.2 (minor singlet from isotope shift) and 7.3
over 2 steps, ∼20% [ H
0
]) as the predominant deuterium-labeled
product. H NMR (300 MHz, CDCl ): δ 0.86 (t, 3H, J = 6.8 Hz, CH
4), 1.16−1.37 (m, ∼11H), 1.67 (quintet, 2H, J = 7.2 Hz, CH -3),
2
2
1
-
3
3
3
1
1
2
both C-1), 14.1 (C-8), 22.6, 28.3−28.6 (m), 28.7−29.1 (m), 29.6−
2
.90−2.04 (m, 4H, CH -4 and CH -7), 2.28 (t, 2H, J = 7.5 Hz, CH -
3
0.6 (m), 30.9, 31.8 (br), 32.8−33.6 ppm (m). GC/MS (EI) m/z: 242
2
2
2
C
1
3
+
•
), 3.64 (s, 3H, RCO CH ), 5.36 ppm (m, 2H, CH-5 and CH-6).
(
1, M ), 184 (0.2), 155 (3), 141 (1), 127 (2), 115 (2), 86 (0.3), 72
2
3
NMR (75 MHz, CDCl ): δ 14.1 (C-14), 22.7, 24.8, 28.9−29.6 (m),
(
57), 71 (47), 58 (71), 57 (73), 43 (100), 41 (70).
3
2
2
30.9, 31.89, 31.91, 32.6 (br), 33.4, 51.4 (RCO CH ), 128.8 (RHC
[
8- H ,9- H0;1;2]-2-(Tetradec-5-yn-1-yloxy)tetrahydro-2H-pyran
2
3
0
;1;2
2
([ H ]-44). Following the procedure described for the synthesis of 17,
CHR), 131.7 (RHCCHR), 174.2 ppm (C-1). GC/MS (EI) m/z:
2
+•
alkyne 18 (700 mg, 3.84 mmol) was deprotonated with n-BuLi (1.50
M in hexanes, 3.07 mL, 4.61 mmol) in THF (38 mL) at −40 °C under
an Ar atmosphere over 2 h and then was reacted with iodide [ H ]-43
242 (1, M ), 223 (0.1), 210 (6), 192 (3), 181 (1), 167 (11), 152 (2),
139 (5), 125 (11), 111 (16), 96 (47), 84 (43), 81 (39), 74 (100), 55
2
(
61).
2
2
2
(
6S)-6-([3- H ,4- H ]-(1S)-1-Hydroxynonyl)tetrahydro-2H-
(
1.10 g, 4.54 mmol) in the presence of HMPA (99%, 1.90 mL, 10.81
0;1;2
0;1;2
2
pyran-2-one ([ H ]-(S,S)-12). Following the procedure described for
mmol) over 12 h. Purification by flash column chromatography (silica
gel, 10% EtOAc in n-hexane) afforded a colorless oil that contained
alkyne [ H ]-44 (800 mg, 2.70 mmol, 70%, ∼20% [ H ]) as the
predominant deuterium-labeled product. H NMR (300 MHz,
CDCl ): δ 0.86 (t, 3H, J = 6.8 Hz, CH -14), 1.22−1.87 (m, ∼21H),
2
CH-1), 3.48 (m, 1H, CH-6′), 3.73 (dt, 1H, J = 9.7, 6.5 Hz, CH-1),
3
2
2
the synthesis of (S,S)-28, alkene [ H ]-(E)-47 (50 mg, 0.21 mmol)
was dihydroxylated with AD-mix-α (Aldrich, 290 mg) and
methanesulfonamide (97%, 21 mg, 0.21 mmol) in a mixture of t-
2
2
2
2
0
1
BuOH and H O (1:1, 6 mL) at 4 °C over 24 h. Purification by flash
2
3
3
column chromatography (silica gel, 40% EtOAc in n-hexane) afforded
.08−2.21 (m, 4H, CH -4 and CH -7), 3.39 (dt, 1H, J = 9.7, 6.3 Hz,
2
2
2
a white solid that contained hydroxylactone [ H ]-(S,S)-12 (4.40 mg,
2
2
13
18.0 μmol, 9%, ∼20% [ H
0
]) as the predominant deuterium-labeled
.85 (m, 1H, CH-6′), 4.56 ppm (dd, 1H, J = 4.3, 2.9 Hz, CH-2′).
C
1
product. Mp: 50−52 °C. H NMR (400 MHz, C D ): δ 0.83−1.58
6
6
NMR (75 MHz, CDCl ): δ 14.1 (C-14), 18.55, 18.63, 18.8, 19.6, 22.7,
2
3
(
m, ∼21H, incl. 0.95 [t, 3H, J = 6.8 Hz, CH -14]), 1.90−2.20 (m, 2H,
3
5.4, 25.5, 26.0, 28.9, 29.0, 29.1 (br), 30.8, 30.9, 31.9, 62.3 (C-6′), 67.1
13
CH -2), 3.22 (m, 1H), 3.58 ppm (m, 1H). C NMR (100 MHz,
2
(
(
(
(
C-1), 79.8 (RCCR), 80.6 (RCCR), 98.8 ppm (C-2′). GC/MS
+
•
C
6
D
6
): δ 14.3 (C-14), 18.4, 23.1, 24.0, 25.8, 25.9, 29.0−30.3 (obscured
EI) m/z: 296 (0.1, M ), 251 (0.1), 223 (2), 195 (1), 181 (4), 167
+
•
m), 29.7, 32.26, 32.28, 32.8−33.2 (m), 73.3, 82.6, 169.8 ppm (C-1).
1), 153 (1), 137 (1), 111 (5), 101 (6), 95 (15), 85 (100, THP ), 67
+
•
+
•
GC/MS (EI) m/z: 243 (0.03, M − H), 225 (0.1), 165 (0.1), 144
0.3), 129 (1), 112 (1), 100 (100), 85 (3), 71 (14), 55 (28), 43 (27),
23), 55 (19). HRMS (ESI) m/z: [M + Na]
calcd for
(
C H D NaO 319.2582, found 319.2563.
1
9
[
32
2
2
+•
2
2
41 (26). HRMS (ESI) m/z: [M + Na] calcd for C14H D NaO
24 2 3
8- H ,9- H0;1;2]-(E)-2-(Tetradec-5-en-1-yloxy)tetrahydro-2H-
0
;1;2
2
267.1905, found 267.1903.
pyran ([ H ]-(E)-45). Following the procedure described for the
synthesis of (E)-23, alkyne [ H ]-44 (400 mg, 1.35 mmol) was
reduced with lithium metal (50 mg, 7.20 mmol) in a mixture of t-
BuOH (3 mL), THF (5 mL), and liquid NH (50 mL) at −78 °C over
2
EtOAc in n-hexane) afforded a colorless oil that contained [ H ]-(E)-
4
deuterium-labeled product. H NMR (300 MHz, CDCl ): δ 0.86 (t,
3
CH -4 and CH -7), 3.36 (dt, 1H, J = 9.6, 6.6 Hz, CH-1), 3.47 (m, 1H,
CH-6′), 3.71 (dt, 1H, J = 9.3, 6.8 Hz, CH-1), 3.84 (m, 1H, CH-6′),
4
CH-6). C NMR (75 MHz, CDCl ): δ 14.1 (C-14), 19.7, 22.7, 25.5,
2
2
2
2
2
(6R)-6-([3- H0;1;2,4- H0;1;2]-(1R)-1-Hydroxynonyl)tetrahydro-2H-
2
2
pyran-2-one ([ H ]-(R,R)-12). Following the procedure described for
2
2
the synthesis of (S,S)-28, alkene [ H ]-(E)-47 (50 mg, 0.21 mmol)
was dihydroxylated with AD-mix-β (Aldrich, 290 mg) and
methanesulfonamide (97%, 21 mg, 0.21 mmol) in a mixture of t-
2
3
h. Purification by flash column chromatography (silica gel, 1%
2
2
BuOH and H O (1:1, 6 mL) at 4 °C over 24 h. Purification by flash
2
2
5 (320 mg, 1.07 mmol, 79%, ∼20% [ H ]) as the predominant
0
column chromatography (silica gel, 40% EtOAc in n-hexane) afforded
1
3
2
a white solid that contained hydroxylactone [ H ]-(R,R)-12 (4.80 mg,
2
H, J = 6.6 Hz, CH -14), 1.18−1.87 (m, ∼21H), 1.90−2.00 (m, 4H,
2
3
1
9.6 μmol, 10%, ∼20% [ H ]) as the predominant deuterium-labeled
0
2
2
product. Mp: 53−54 °C. This compound was spectroscopically
identical to [ H ]-(S,S)-12. HRMS (ESI) m/z: [M + Na] calcd for
2
+•
2
.55 (dd, 1H, J = 4.4, 2.8 Hz, CH-2′); 5.37 ppm (m, 2H; CH-5 and
C H D NaO 267.1905, found 267.1900.
13
14 24
2
3
3
Synthesis of Deuterium-Labeled Monooxygenated Esters.
,10-Tetradecanediol (51). Reduction of 17 (580 mg, 1.45 mmol)
6.3, 29.0−29.7 (obscured m), 29.2, 30.8, 30.9, 31.9, 32.4, 32.5
1
(
obscured m), 62.3 (C-6′), 67.5 (C-1), 98.8 (C-2′), 129.9 (RHC
was carried out with H (g) and Pd/C (10%, 72 mg) in MeOH (10
2
+•
CHR), 130.8 ppm (RHCCHR). GC/MS (EI): m/z: 298 (0.1, M ),
mL) over 18 h following the procedure described for the synthesis of
erythro-29. The THP moiety of the crude product was then cleaved
2
1
54 (0.1), 225 (1), 195 (1), 183 (0.2), 167 (0.3), 156 (0.1), 125 (1),
+•
11 (1), 101 (2), 97 (2), 85 (100, THP ), 67 (17), 55 (15). HRMS
with p-TsOH·H O (100 mg, cat.) in MeOH (10 mL) over 4 h, as
2
+•
(
ESI) m/z: [M + Na] calcd for C H D NaO 321.2739, found
19 34 2 2
described for the synthesis of erythro-38. Purification by flash column
3
21.2724.
chromatography (silica gel, 9% to 67% Et O in petroleum spirits 40−
2
2
2
2
[
8- H ,9- H ]-(E)-5-Tetradecen-1-ol ([ H ]-(E)-46). As de-
60) afforded the diol 51 (328 mg, 1.42 mmol, 98% over 2 steps) as a
0
;1;2
0;1;2
2
2
1
scribed for the synthesis of (E)-24, the THP moiety of [ H ]-(E)-
4
white solid. Mp: 55−56 °C. H NMR (400 MHz, CDCl ): δ 0.89 (t,
2
3
5 (320 mg, 1.07 mmol) was cleaved with p-TsOH.H O (5 mg, cat.)
3H, J = 7.0 Hz, CH -14), 1.20−1.50 (m, 22H), 1.54 (m, 2H), 3.56 (m,
2
3
1
3
in MeOH (10 mL) over 2 h to afford a colorless oil that contained
1H, CH-10), 3.62 ppm (t, 2H, J = 6.6 Hz, CH -1). C NMR (100
2
2
2
[
H ]-(E)-46 (230 mg, 1.07 mmol, quantitative, ∼20% [ H ]) as the
MHz, CDCl ): δ 14.1 (C-14), 22.8, 25.6, 25.7, 27.8, 29.4, 29.5 (2C),
2
0
3
1
predominant deuterium-labeled product. H NMR (300 MHz,
CDCl ): δ 0.86 (t, 3H, J = 6.8 Hz, CH -14), 1.18−1.46 (m, ∼15H),
1
29.7, 32.8, 37.2, 37.5, 63.1 (C-1), 72.0 ppm (C-10). GC/MS (EI) m/z:
207 (0.4), 186 (0.3), 173 (12), 155 (5), 137 (26), 124 (2), 109 (4),
101 (1), 95 (68), 87 (37), 86 (38), 81 (70), 69 (100), 67 (32), 57
3
3
.90−2.04 (m, 4H, CH -4 and CH -7), 3.62 (t, 2H, J = 6.5 Hz, CH -
2
2
2
13
+•
1
), 5.38 ppm (m, 2H, CH-5 and CH-6). C NMR (75 MHz, CDCl ):
(32), 55 (45), 43 (22), 41 (39). HRMS (ESI) m/z: [M + Na] calcd
3
δ 14.1 (C-14), 22.7, 25.7, 28.9−29.7 (m), 31.9 (br), 32.3, 32.4−32.6
for C H NaO 253.2143, found 253.2141. Anal. Calcd for C H O :
C, 72.99; H, 13.12. Found: C, 72.99; H, 13.20.
14
30
2
14 30
2
(
m), 62.9 (C-1), 129.7 (RHCCHR), 130.9 ppm (RHCCHR).
S
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
1
0-Oxotetradecanoic acid (48). Jones’ reagent (8 N) was added
(13), 71 (55), 59 (35), 43 (35). HRMS (ESI) m/z: [M + Na]+ calcd
•
dropwise to a solution of diol 51 (280 mg, 1.22 mmol) in acetone (10
mL) with stirring at 0 °C until the orange color of the reaction mixture
persisted. The reaction mixture was allowed to warm to room
temperature with stirring over 30 min and then was quenched with
for C H D NaO 285.2344, found 285.2333.
1-(Tetrahydro-2H-pyran-2-yloxy)tetradecan-6-ol (52). 1-Bro-
mooctane (0.2 mL, 1.15 mmol) was added dropwise to a mixture of
15
26
4
3
magnesium (217 mg, 8.93 mmol) and I
mL) with stirring at 0 °C under a N atmosphere, in order to initiate
formation of the Grignard reagent. When the resulting yellow solution
became colorless, it was diluted with anhydrous Et O (4 mL), and
(cat.) in anhydrous Et O (2
2
2
water (20 mL). The mixture was extracted with Et O (6 × 20 mL),
2
2
and the combined organic extract was washed with brine (2 × 20 mL)
and then extracted with aqueous NaOH solution (5%, 6 × 20 mL).
The combined basic aqueous extract was cooled to 0 °C, and
concentrated aqueous HCl (32%, 30 mL) was added dropwise until
the solution was strongly acidic. The acidic aqueous solution was
2
additional 1-bromooctane (0.4 mL, 2.29 mmol) was added dropwise.
The Grignard reagent mixture was allowed to warm to room
temperature with continuous stirring for 1 h and then was cooled to
2
4
0
°C. A solution of aldehyde 50 (360 mg, 1.80 mmol) in anhydrous
2
extracted with Et O (6 × 20 mL), and the combined organic extract
2
Et O (1 mL) was added dropwise, and the reaction mixture was
was then washed with brine (20 mL), dried over anhydrous MgSO4,
allowed to warm to room temperature and stirred for a further 1.5 h.
The reaction mixture was quenched with saturated aqueous NH Cl
and filtered. The solvent was removed in vacuo to afford ketoacid 48
4
7
(
6
285 mg, 1.18 mmol, 97%) as a white solid. Mp: 66−68 °C (lit. mp:
4
1
(20 mL) and extracted with Et O (3 × 10 mL). The combined organic
7.6−68.6 °C). H NMR (400 MHz, CDCl ): δ 0.88 (t, 3H, J = 7.3
2
3
extract was washed with brine (3 × 10 mL), dried over anhydrous
Hz, CH -14), 1.18−1.36 (m, 10H), 1.47−1.65 (m, 6H), 2.29−2.39
3
MgSO , filtered, and concentrated in vacuo. The crude product was
ppm (m, 6H, CH -2, CH -9 and CH -11, incl. 2.32 [t, 2H, J = 7.5 Hz,
4
2
2
2
13
purified by flash column chromatography (silica gel, 9% EtOAc in n-
hexane) to afford 52 (398 mg, 1.27 mmol, 70%) as a yellow oil. H
CH -2]). C NMR (100 MHz, CDCl ): δ 13.8 (C-14), 22.4, 23.8,
2
3
1
2
4.6, 26.0, 28.9, 29.0, 29.1 (2C), 34.0, 42.5, 42.7, 179.7 (C-1), 211.8
+
•
NMR (500 MHz, CDCl ): δ 0.86 (t, 3H, J = 7.0 Hz, CH -14), 1.20−
ppm (C-10). GC/MS (EI) m/z: (as methyl ester) 256 (1, M ), 227
3
3
+•
1.65 (m, 27H), 1.69 (m, 1H), 1.80 (m, 1H), 3.37 (dt, 1H, J = 9.6, 6.6
Hz, CH-1), 3.48 (m, 1H, CH-6′), 3.57 (m, 1H, CH-6), 3.72 (m, 1H,
(
1
3), 225 (15, M − OCH ), 214 (23), 199 (25), 182 (6), 171 (9),
3
69 (10), 157 (30), 155 (1), 143 (1), 141 (5), 139 (37), 125 (85), 121
1
3
+
•
CH-1), 3.85 (m, 1H, CH-6′), 4.55 ppm (m, 1H, CH-2′). C NMR
(
28), 113 (13), 101 (17), 97 (52), 87 (12, C H O ), 85 (100,
4 7 2
+
•
+•
(125 MHz, CDCl ): (mixture of diastereomers) δ 14.1 (C-14), 19.72,
3
C H O ), 74 (12), 69 (40), 59 (21, C H O ), 58 (69), 57 (99,
C H ), 55 (67), 43 (30), 41 (50). HRMS (ESI) m/z: [M + Na]
5
9
2
3
2
+•
+•
19.74, 22.7, 25.4, 25.5, 25.7, 26.28, 26.34, 29.3, 29.6, 29.7, 30.8, 31.9,
4
9
3
(
7.4, 37.5, 62.39 (C-6′), 62.43 (C-6′), 67.5 (C-1), 67.6 (C-1), 71.89
C-6), 71.93 (C-6), 98.89 (C-2′), 98.91 ppm (C-2′). GC/MS (EI) m/
z: 229 (0.2), 213 (0.2), 171 (0.1), 157 (1), 143 (0.4), 129 (0.3), 115
calcd for C H NaO 265.1780, found 265.1778. Anal. Calcd for
14
26
3
C H O : C, 69.38; H, 10.81. Found: C, 69.38; H, 10.83.
1
4
26
3
2
2
2
Methyl [9- H ,11- H ]-10-oxotetradecanoate ([ H ]-13). Fol-
0
;1;2
0;1;2
4
+•
+•
2
(1), 101 (22, THPO ), 99 (8), 85 (100, THP ), 84 (11), 83 (13), 81
lowing the procedure described for the synthesis of [ H ]-(S,S)-32,
4
(
(
3
1
11), 69 (21), 67 (12), 57 (34), 56 (15), 55 (52), 44 (9), 43 (44), 42
14), 41 (57). HRMS (ESI) m/z: [M + Na] calcd for C H NaO
37.2719, found 337.2708. Anal. Calcd for C H O : C, 72.56; H,
2.18. Found: C, 72.43; H, 12.19.
1,6-Tetradecanediol (53). The THP moiety of 52 (202 mg, 0.64
ketoacid 48 (218 mg, 0.90 mmol) was deuterated with NaOD/D O
2
+•
1
9
38
3
over 7 days and esterified with ethereal CH N in MeOH (5 mL) at 0
2
2
1
9
38
3
°
6
C. Purification by flash column chromatography (silica gel, 5% to
6% Et O in petroleum spirits 40−60) afforded a pale yellow, low-
2
2
melting solid that contained ketoester [ H ]-13 (223 mg, 0.86 mmol,
9
product. H NMR (400 MHz, CDCl ): δ 0.88 (t, 3H, J = 7.3 Hz, CH -
4
mmol) was cleaved with p-TsOH.H O (5 mg, cat.) in MeOH (5 mL)
2
2
5% over two steps, ≤1% [ H ]) as the major deuterium-labeled
0
over 3 h, as described for the synthesis of (E)-24. Purification by flash
column chromatography (silica gel, 50% EtOAc in n-hexane) afforded
1
3
3
1
7
4), 1.18−1.33 (m, 10H), 1.51 (m, 4H), 1.59 (m, 2H), 2.27 (t, 2H, J =
diol 53 (142 mg, 0.62 mmol, 96%) as a pale yellow solid. Mp: 56−58
.5 Hz, CH -2), 2.30−2.37 (m, 0.1H, residual hydrogen from CH or
1
2
2
°
C. H NMR (500 MHz, CDCl ): δ 0.86 (t, 3H, J = 7.0 Hz, CH -14),
2
2
3
3
CHD at C-9 and/or C-11 of [ H ]-[ H ]-analogues), 3.64 ppm (s, 3H,
RCO CH ). C NMR (100 MHz, CDCl ): δ 13.8 (C-14), 22.3, 23.7,
0
3
1
.18−1.60 (m, 24H), 3.57 (m, 1H, CH-6), 3.63 ppm (t, 2H, J = 6.6
Hz, CH -1). C NMR (125 MHz, CDCl ): δ 14.1 (C-14), 22.7, 25.4,
13
2
3
3
13
2
3
2
4.9, 25.8, 29.0 (2C), 29.1, 29.2, 34.1, 41.3−42.7 (m, incl. 41.8
2
5.7, 25.8, 29.3, 29.6, 29.7, 31.9, 32.7, 37.4, 37.6, 62.9 (C-1), 71.9 ppm
[
quintet, J = 19.0 Hz, CD ], 42.2 [quintet, J = 19.0 Hz, CD ], C-
C,D
2
C,D
2
(C-6). GC/MS (EI) m/z: 157 (0.1), 145 (0.2), 143 (3), 117 (17,
9
and C-11), 51.4 (RCO CH ), 174.3 (C-1), 211.9 ppm (C-10). GC/
+•
2
3
C H O ), 99 (36), 85 (2), 83 (20), 82 (12), 81 (68), 71 (10), 70
+
•
+•
6
13
2
MS (EI) m/z: 260 (2, M ), 231 (3), 229 (23, M − OCH ), 218
3
(
4
21), 69 (55), 67 (14), 57 (66), 56 (11), 55 (100), 44 (25), 43 (89),
2 (44), 41 (98). HRMS (ESI) m/z: [M + Na] calcd for
(
31), 201 (27), 186 (8), 169 (10), 159 (9), 157 (42), 145 (7), 143 (7),
+•
+•
141 (41), 125 (92), 115 (9), 97 (50), 87 (91, C H D O and/or
5 7 2
C H NaO 253.2143, found 253.2135. Anal. Calcd for C H O :
14
30
2
14 30
2
+
•
+•
+•
C H O ), 74 (31), 62 (79), 59 (100, C H D and/or C H O ),
5
4
7
2
4
7
2
2
3
2
C, 72.99; H, 13.12. Found: C, 72.82; H, 13.32.
-Oxotetradecanoic acid (49). Diol 53 (136 mg, 0.59 mmol) was
+•
5 (65), 43 (48). HRMS (ESI) m/z: [M + Na] calcd for
6
C H D NaO 283.2187, found 283.2184.
15
24
4
3
oxidized with Jones’ reagent (8 N) in acetone (5 mL) at 0 °C, as
described for the synthesis of 48. Purification by acid−base extraction
afforded ketoacid 49 (138 mg, 0.57 mmol, 96%) as a white solid. Mp:
2
2
2
Methyl [9- H ,11- H ]-10-hydroxytetradecanoate ([ H ]-14).
0
;1;2
0;1;2
4
2
Ketoester [ H ]-13 (122 mg, 0.47 mmol) was reduced with NaBH
4
4
4
9
1
(
31 mg, 0.82 mmol) in a mixture of MeOH (2 mL) and Et O (2 mL)
2
67−69 °C (lit. mp: 68−69 °C). H NMR (500 MHz, CDCl ): δ
3
over 2 h, as described for the synthesis of (S,S)-33. Purification by flash
0
.85 (t, 3H, J = 7.2 Hz, CH -14), 1.20−1.30 (m, 10H), 1.55 (m, 2H,
3
column chromatography (silica gel, 17% to 66% Et O in petroleum
2
CH -8), 1.60 (m, 4H, CH -3 and CH -4), 2.31−2.42 ppm (m, 6H,
2
2
2
13
spirits 40−60) afforded a white solid that contained hydroxyester
CH -2, CH -5 and CH -7). C NMR (100 MHz, CDCl ): δ 14.0 (C-
2
2
2
3
2
2
[
H ]-14 (116 mg, 0.44 mmol, 94%, ≤1% [ H ]) as the major
4
0
14), 22.6 (C-13), 23.1 (C-4), 23.9 (C-8), 24.2 (C-3), 29.1, 29.2, 29.3,
48
deuterium-labeled product. Mp: 34−36 °C (lit. mp: (unlabeled
3
1.8 (C-12), 33.7 (C-2), 42.2 (C-5), 42.9 (C-7), 179.0 (C-1), 211.0
1
+•
compound) 35.5−36 °C). H NMR (500 MHz, CDCl ): δ 0.88 (t,
3
ppm (C-6). GC/MS (EI) m/z: (as methyl ester) 225 (0.5, M
−
3H, J = 7.0 Hz, CH -14), 1.20−1.45 (m, 15H), 1.59 (m, 2H), 2.27 (t,
2H, J = 7.6 Hz, CH -2), 3.53 (m, 1H, CH-10), 3.63 ppm (s, 3H,
OCH ), 171 (1), 158 (23), 143 (8), 141 (11), 126 (41), 115 (6), 111
3
3
2
(38), 101 (13), 98 (17), 84 (16), 83 (18), 73 (16), 71 (37), 59 (33),
13
RCO CH ). C NMR (125 MHz, CDCl ): δ 14.1 (C-14), 22.7, 24.9,
58 (19), 57 (63), 55 (94), 43 (100), 41 (95). HRMS (ESI) m/z: [M +
2
3
3
+
•
2
5
2
2
5.4, 27.6, 29.1, 29.2, 29.4, 29.5, 34.1, 35.9−36.9 (m, C-9 and C-11),
Na] calcd for C H NaO 265.1780, found 265.1775. Anal. Calcd
14 26 3
1.4 (RCO CH ), 71.7 (C-10), 174.3 ppm (C-1). GC/MS (EI) m/z:
for C H O : C, 69.38; H, 10.81. Found: C, 69.31; H, 10.69.
2
3
14 26
3
+•
+•
+•
2
2
2
61 (0.1, M − H), 245 (0.4, M − OH), 244 (0.4, M − H O),
Methyl [5- H ,7- H ]-6-oxotetradecanoate ([5,5,7,7- H ]-15).
As described for the synthesis of [ H ]-(S,S)-32, ketoacid 49 (116 mg,
2
0;1;2
0;1;2
4
+•
+•
2
31 (1, M − OCH ), 229 (2), 212 (4), 203 (28, M − C H D
3
4
7
2
4
+
•
and/or M − C H O ), 193 (1), 174 (38), 171 (100), 157 (3), 153
0.48 mmol) was deuterated with NaOD/D O over 9 days, and the
2
3
2
2
2
(
(
6), 143 (34), 131 (33), 129 (10), 125 (18), 115 (5), 105 (1), 101
15), 89 (17), 87 (99, C H D O and/or C H O ), 74 (66), 73
crude [ H ]-49 was then esterified with CH N in Et O (2 mL) at 0
4
2
2
2
+
•
+•
°C. Purification by flash column chromatography (silica gel, 25% to
5
7
2
4
7
2
T
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
+
•
6
6% Et O in petroleum spirits 40−60) afforded a yellow, low-melting
109 (2), 101 (4), 85 (100, THP ), 67 (11), 57 (8), 55 (20), 43 (9),
2
2
+•
solid that contained ketoester [5,5,7,7- H ]-15 (79 mg, 0.30 mmol,
41 (16). HRMS (ESI) m/z: [M + Na] calcd for C H NaO
417.2981, found 417.2975. Anal. Calcd for C H O : C, 73.05; H,
10.73. Found: C, 73.09; H, 10.61.
4
24 42
4
2
6
3% over two steps, ≤1% [ H ]) as the major deuterium-labeled
0
24 42 4
1
product. H NMR (400 MHz, CDCl ): δ 0.87 (t, 3H, J = 7.2 Hz, CH -
3
3
2
2
2
1
4
3
4), 1.21−1.29 (m, 10H), 1.50−1.57 (m, 2H, CH -8), 1.57−1.67 (m,
[7- H ,8- H ]-1,6-Tetradecanediol ([ H ]-53). A solution of 54
2
0;1;2 0;1;2 4
H, CH -3 and CH -4), 2.32 (t, 2H, J = 6.6 Hz, CH -2), 3.66 ppm (s,
H, RCO CH ). C NMR (100 MHz, CDCl ): δ 14.1 (C-14), 22.6
(276 mg, 0.70 mmol) in benzene (8 mL) was degassed−purged twice
with N2 (g) and then twice with 2
(g). Wilkinson’s catalyst
2
2
2
13
H
2
2
3
3
(
C-13), 23.1 (C-4), 23.7 (C-8), 24.4 (C-3), 29.1, 29.2, 29.4, 31.8, 33.8
(tris(triphenylphosphine)rhodium(I) chloride, 150 mg, 0.16 mmol)
2
(
C-2), 41.1−42.6 (m, incl. 41.5 [quintet, J = 19.0 Hz, CD ], 42.1
was added, and the reaction mixture was stirred under a H (D , 99.98
C,D
2
2
2
[
quintet, J = 19.2 Hz, CD ], C-5 and C-7), 51.5 (RCO CH ), 173.9
atom % D) atmosphere at room temperature for 18 h. The mixture
was diluted with n-hexane (50 mL) and filtered through a pad of Celite
that was washed thoroughly with additional n-hexane. The filtrate was
concentrated under reduced pressure, and the residue was dissolved in
C,D
2
2
3
+
•
(
C-1), 211.2 ppm (C-6). GC/MS (EI) m/z: 260 (0.2, M ), 229 (1,
+
•
M
(
− OCH ), 173 (1), 162 (27), 145 (10), 143 (12), 130 (46), 117
3
9), 113 (28), 112 (32), 102 (23), 101 (28), 99 (8), 87 (8), 85 (20),
7
5
5 (18), 74 (15), 73 (35), 71 (15), 62 (18), 59 (82), 57 (88), 56 (49),
MeOH (10 mL). p-TsOH·H
reaction mixture was stirred at room temperature for 16 h. Solid
NaHCO (200 mg) was added to quench the reaction, and the solvent
2
O (50 mg, cat.) was added, and the
5 (47), 45 (47), 44 (49), 43 (100), 41 (84). HRMS (ESI) m/z: [M +
+
•
Na] calcd for C H D NaO 283.2187, found 283.2182.
3
15
24
4
3
2
2
Methyl [5- H
,7- H
]-6-hydroxytetradecanoate
was evaporated in vacuo. The residue was purified by flash column
0
;1;2
0;1;2
2
2
([5,5,7,7- H ]-16). Ketoester [5,5,7,7- H ]-15 (44 mg, 0.17 mmol)
chromatography (silica gel, 10% to 66% Et O in petroleum spirits 40−
4
4
2
2
was reduced with NaBH (11 mg, 0.29 mmol) in MeOH (5 mL) over
60) to afford a white solid that contained [ H ]-53 (131 mg, 0.56
4
4
2
25 min, as described for the synthesis of (S,S)-33. Purification by flash
mmol, 80% over 2 steps, ≤1% [ H ]) as the major deuterium-labeled
0
1
column chromatography (silica gel, 17% EtOAc in n-hexane) afforded
a yellow, crystalline solid that contained [5,5,7,7- H ]-16 (39 mg, 0.15
product. Mp: 54−55 °C. H NMR (400 MHz, CDCl ): δ 0.86 (t, 3H,
3
2
4
J = 6.9 Hz, CH -14), 1.18−1.50 (m, 18H), 1.57 (m, 2H), 3.57 (m, 1H,
3
2
13
mmol, 88%, ≤1% [ H ]) as the major deuterium-labeled product. Mp:
CH-6), 3.62 ppm (t, 2H, J = 6.6 Hz, CH -1). C NMR (100 MHz,
0
2
1
3
2−34 °C. H NMR (400 MHz, CDCl ): δ 0.86 (t, 3H, J = 7.2 Hz,
CDCl ): (signals for C-7 and C-8 not observed) δ 14.1 (C-14), 22.7,
3
3
CH -14), 1.18−1.70 (m, 17H), 2.31 (t, 2H, J = 6.6 Hz, CH -2), 3.56
25.4, 25.8, 29.3, 29.4, 29.5, 31.9, 32.7, 37.3, 62.9 (C-1), 71.8 ppm (C-
3
2
13
(
m, 1H, CH-6), 3.65 ppm (s, 3H, RCO CH ). C NMR (100 MHz,
6). GC/MS (EI) m/z: 215 (0.2), 207 (0.2), 198 (0.1), 186 (0.1), 173
2
3
+•
CDCl ): δ 14.1 (C-14), 22.6 (C-13), 24.8, 25.0, 25.4, 29.2, 29.57,
2
Hz, CD ], 36.8 [quintet, J = 19.2 Hz, CD ], C-5 and C-7), 51.5
(1), 160 (1), 147 (15), 129 (3), 117 (47, C H D
and/or
C H O ), 99 (90), 87 (11), 85 (25), 81 (100), 73 (14), 71 (45), 70
3
8
13
4
+
•
9.61, 31.9, 34.0 (C-2), 35.6−37.1 (m, incl. 36.1 [quintet, JC,D = 19.0
6
13
2
(62), 59 (17), 57 (45), 55 (58), 45 (12), 43 (48). HRMS (ESI) m/z:
2
C,D
2
+
•
(
RCO CH ), 71.5 (C-6), 174.2 ppm (C-1). GC/MS (EI) m/z: 147
[M + Na] calcd for C H D NaO 257.2395, found 257.2395.
2
3
14 26 4 2
2
2
2
(
21), 118 (26), 115 (57), 101 (3), 99 (3), 88 (40), 87 (100), 85 (7),
Methyl [7- H ,8- H ]-6-oxotetradecanoate ([7,7,8,8- H ]-15).
Diol [ H ]-53 (118 mg, 0.50 mmol) was oxidized with PDC (98%,
0;1;2
0;1;2
4
2
7
5
4 (11), 73 (5), 71 (10), 70 (11), 69 (26), 68 (15), 59 (27), 58 (19),
7 (35), 56 (24), 55 (34), 45 (20), 44 (22), 43 (59), 42 (28), 41 (51).
4
924 mg, 2.41 mmol) in DMF (10 mL) under an Ar atmosphere over
18 h, following the procedure described for the synthesis of (S,S)-31.
The crude acid obtained was then esterified with ethereal CH N in
+•
HRMS (ESI) m/z: [M + Na] calcd for C H D NaO 285.2344,
found 285.2336.
15
26
4
3
2
2
2
-(6-(Tetrahydro-2H-pyran-2-yloxy)tetradec-7-ynyloxy)tetra-
MeOH (5 mL) at 0 °C, as described for the synthesis of (S,S)-32.
hydro-2H-pyran (54). A solution of n-BuLi (1.10 M in hexanes, 4.0
Purification by flash column chromatography (silica gel, 5% to 66%
mL, 4.40 mmol) was added dropwise to a solution of 1-octyne (96%,
.0 mL, 6.51 mmol) in anhydrous THF (5 mL) with stirring under a
Et O in petroleum spirits 40−60) afforded a pale yellow, low-melting
2
2
1
solid that contained [7,7,8,8- H ]-15 (93 mg, 0.36 mmol, 71% over
4
2
1
N atmosphere at −40 °C. The solution was stirred at −40 °C for 3 h,
two steps, ≤1% [ H ]) as the major deuterium-labeled product. H
2
0
24
then a solution of aldehyde 50 (257 mg, 1.28 mmol) in anhydrous
THF (5 mL) was added dropwise. The reaction mixture was allowed
to warm to room temperature and stirred for a further 42 h. Saturated
NMR (400 MHz, CDCl ): δ 0.85 (t, 3H, J = 6.9 Hz, CH -14), 1.17−
3
3
1.30 (m, 10H), 1.51−1.64 (m, 4H), 2.29 (t, 2H, J = 7.1 Hz, CH -2),
2
1
3
2.39 (t, 2H, J = 7.0 Hz, CH -5), 3.64 ppm (s, 3H, RCO CH ).
C
2
2
3
aqueous NH Cl solution (20 mL) was added to quench the reaction,
and the mixture was extracted with Et O (6 × 20 mL). The combined
organic extract was washed with brine (20 mL), dried over anhydrous
MgSO , filtered, and concentrated in vacuo. The crude propargylic
alcohol was dissolved in CH Cl (30 mL), and p-TsOH·H O (200 mg,
NMR (100 MHz, CDCl ): δ 14.1 (C-14), 22.6 (C-13), 23.0 (obscured
4
3
2
quintet, JC,D = 19.3 Hz, CD at C-8), 23.1, 24.5, 29.0, 29.1, 29.3, 31.8
2
(C-12), 33.8 (C-2), 42.0 (obscured quintet, JC,D = 19.1 Hz, CD at C-
2
4
7), 42.2 (C-5), 51.5 (RCO CH ), 173.8 (C-1), 211.1 ppm (C-6). GC/
2
3
+•
+•
2
2
2
MS (EI) m/z: 260 (1, M ), 229 (3, M − OCH ), 211 (5), 183 (2),
173 (4), 160 (69), 159 (10), 145 (30, C H D O ), 143 (21, M
3
+
•
+•
cat.) was added. The solution was cooled to 0 °C with stirring under a
−
9
13
4
+
•
N atmosphere, and DHP (97%, 0.4 mL, 4.25 mmol) was added
C H D ), 128 (100), 117 (2), 115 (17, M − C H D O), 111 (71),
2
8
13
4
9
13
4
dropwise. The reaction mixture was allowed to warm to room
temperature and stirred for a further 18 h. Aqueous NaOH solution
5%, 50 mL) was added to quench the reaction, and the layers were
separated. The aqueous layer was extracted with CH Cl (6 × 20 mL),
and the combined organic extract was washed with brine (2 × 20 mL),
dried over anhydrous MgSO , filtered, and concentrated in vacuo. The
101 (34), 100 (35), 87 (14), 85 (21), 83 (39), 73 (45), 71 (11), 59
(49), 57 (23), 55 (54), 43 (40). HRMS (ESI) m/z: [M + Na]+ calcd
for C H D NaO 283.2187, found 283.2181.
•
(
1
5
24
4
3
2
2
2
2
Methyl [7,7,8,8- H ]-6-hydroxytetradecanoate ([7,7,8,8- H ]-16).
Ketoester [7,7,8,8- H ]-15 (25 mg, 96.0 μmol) was reduced with
4
4
2
4
4
NaBH (7 mg, 185.0 μmol) in a mixture of MeOH (2 mL) and Et O
4
2
crude product was purified by flash column chromatography (silica gel,
(2 mL) at 0 °C over 4 h, as described for the synthesis of (S,S)-33.
1
% to 5% Et O in petroleum spirits 40−60) to afford 54 (374 mg, 0.95
Purification by flash column chromatography (silica gel, 17% to 66%
2
1
mmol, 74% over 2 steps) as a colorless oil. H NMR (500 MHz,
Et O in petroleum spirits 40−60) afforded a white solid that contained
2
2
2
CDCl ): δ 0.87 (t, 3H, J = 7.1 Hz, CH -14), 1.20−1.65 (m, 22H),
[7,7,8,8- H ]-16 (22 mg, 83.8 μmol, 87%, ≤1% [ H ]) as the major
3
3
4
0
1
1
.65−1.75 (m, 4H), 1.75−1.88 (m, 2H), 2.17 (td, 2H, J = 7.1, 1.9 Hz,
2
deuterium-labeled product. Mp: 34−36 °C. H NMR (400 MHz,
CDCl ): δ 0.86 (t, 3H, J = 6.9 Hz, CH -14), 1.19−1.55 (m, 15H), 1.63
CH -9), 3.37 (m, 1H, CH-1), 3.48 (m, 2H, CH-6′ and CH-6″), 3.72
3
3
(
m, 1H, CH-1), 3.78 (m, 1H), 3.85 (m, 1H), 4.36 (tt, 1H, J = 6.7, 1.9
(m, 2H), 2.31 (t, 2H, J = 7.5 Hz, CH -2), 3.56 (m, 1H, CH-6), 3.65
2
13
Hz, CH-6), 4.55 (dd, 1H, J = 4.3, 2.8 Hz, CH-2′), 4.95 ppm (dd, 1H, J
ppm (s, 3H, RCO CH ). C NMR (100 MHz, CDCl ): (Signals for
2
3
3
1
3
=
4.0, 2.9 Hz, CH-2″). C NMR (125 MHz, CDCl ): (mixture of
C-7 and C-8 not observed) δ 14.1 (C-14), 22.7, 24.9, 25.2, 29.3, 29.4,
29.5, 31.9, 34.0, 37.0 (C-5), 51.5 (RCO CH ), 71.6 (C-6), 174.2 ppm
3
diastereomers) δ 14.0 (C-14), 18.7, 19.5, 19.7, 22.6, 25.40, 25.41,
2
3
+
•
2
6
7
5.50, 25.53, 26.05, 26.06, 28.5, 28.7, 29.7, 30.6, 30.8, 31.3, 36.1 (C-5),
2.3 (2C, C-6′ and C-6″), 65.2 (C-6), 67.6 (C-1), 78.9 (C-8), 86.0 (C-
), 95.3 (C-2″), 98.8 ppm (C-2′). GC/MS (EI) m/z: 309 (0.2), 293
(C-1). GC/MS (EI) m/z: 244 (0.3), 231 (0.4, M − OCH ), 229 (1),
212 (3), 194 (1), 170 (3), 161 (2), 160 (15), 145 (32, M
C H D ), 128 (24), 116 (33), 113 (69), 101 (13), 100 (16), 87
3
+
•
−
8
13
4
(
1), 275 (0.3), 225 (1), 207 (1), 171 (1), 135 (1), 121 (1), 115 (1),
(100), 85 (63), 74 (29), 73 (20), 71 (19), 67 (30), 59 (34), 57 (37),
U
dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Featured Article
5
5 (66), 43 (55), 41 (52). HRMS (ESI) m/z: [M + Na]+• calcd for
C H D NaO 285.2344, found 285.2340.
In Vivo Deuterium Incorporation Studies. Fruit Flies. No
Markus Riegler (Hawkesbury Institute for the Environment,
University of Western Sydney) for the supply of fruit fly pupae.
15
26
4
3
permission from national or local authorities was required to perform
in vivo studies with fruit flies. B. cacuminata pupae were hatched out
and housed in a cotton mesh cage at room temperature. They were fed
a diet of sugar (sucrose), water, and a concentrated yeast extract and
were subjected to a normal light−dark cycle. Feeding experiments
were conducted at least 10 days after emergence because B. cacuminata
are sexually mature at this time.
Preparation of Precursors and Equipment. The potential
precursors and β-oxidation inhibitor 2-fluorostearic acid were dissolved
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(
4
1) Booth, Y. K.; Kitching, W.; De Voss, J. J. Nat. Prod. Rep. 2009, 26,
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9) When referring to an aliphatic chain, this notation describes the
33
(
(
in Et O and enough sucrose was added to form ∼2% w/w compound-
2
to-sucrose mixtures. The mixtures were thoroughly stirred, then Et O
2
(
was evaporated and the mixtures were placed under high vacuum for
∼2 h. Feeding experiments were carried out at 28 °C in 100 mL
(
conical flasks sealed with fresh rubber septa. The conical flasks were
thoroughly rinsed with n-hexane, ethanol, concentrated aqueous HCl
solution, water, and acetone and were then baked in an oven at 150 °C
for several days prior to their use.
(
(
Administration of Potential Spiroacetal Precursors to Flies and
Deuterium Incorporation Analysis. Five male flies were placed in a
flask with three small pieces of sponge soaked in water and
approximately 10 mg of the compound−sucrose mixture. Control
groups were fed sucrose in a similar manner. In experiments involving
the coadministration of 2-fluorostearic acid, the deuterated com-
pound−sugar mixture was introduced to the flies ∼6−18 h following
the administration of the 2-fluorostearic acid−sugar mixture. Sampling
of the headspace volatile emissions was carried out using Supelco
SPME units with 75 μm carboxen-PDMS fibers. The SPME fiber was
inserted into the experiment flask through the rubber septum and
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the septum was removed from the flask for 15 s to allow air to enter
and carbon dioxide to escape from the flask. The SPME fiber was then
inserted into the GC/MS injection port, allowing direct analysis of the
adsorbed volatiles. SPME sampling34 was carried out once a day
following administration of the deuterated compounds for 5 days or
until the flies had died. GC/MS program: DB-5 column (30 m, J&W
2
(
distance between the position of interest and the chain terminus (often
a methyl group), referred to as the ω position. The position adjacent
to the terminus is described as the ω-1 position, the one two bonds
away from the terminus is the ω-2 position, then the ω-3 position, and
so forth. Thus, ω-n describes the position n bonds away from the
terminus.
10) Fletcher, M. T.; Mazomenos, B. E.; Georgakopoulos, J. H.;
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(
(
2
(
−1
Scientific): splitless mode; column flow 1.6 mL min ; total flow 78.8
−1
mL min ; injector 250 °C; detector 250 °C; oven 40 °C (1.0 min
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−1
equilibration) held for 4.0 min, ramp 10 °C min to 270 °C and held
for 25.0 min (total program time 52.0 min). Masses monitored in SIM
experiments: m/z 55, 57, 58, 73, 77, 83, 85, 86, 98, 99, 100, 101, 102,
1
03, 104, 105, 111, 113, 114, 115, 126, 128, 130, 156, 157, 158, 159,
160, 161, 162.
(
16) All of the synthesized (S,S) compounds had negative optical
rotations, while all the (R,R) isomers exhibited positive optical
ASSOCIATED CONTENT
■
24
24
rotations, e.g., (S,S)-28: [α]D −18.2 (c 0.61, MeOH); (R,R)-28: [α]D
19.6 (c 0.75, MeOH). A similar result was observed previously with
* Supporting Information
S
+
Materials and general methods, copies of H and 13C NMR
spectra of new compounds and final products, an explanation of
the categories and criteria used for qualitative classification of in
vivo deuterium incorporation from labeled substrates into
spiroacetals, and characteristic spiroacetal mass fragmentation
patterns. This material is available free of charge via the Internet
at http://pubs.acs.org.
1
(7S,8S)- and (7R,8R)-methyl 7,8-dihydroxytetradecanoate synthesized
via SAD (Singh, A. A.; Zulkifli, S. N. A.; Meyns, M.; Hayes, P. Y.; De
Voss, J. J. Tetrahedron: Asymmetry 2011, 22, 1709−1719), where
stereochemical assignments were confirmed by comparison with
material derived from chiral, nonracemic tartrate substrates (Cryle, M.
J.; De Voss, J. J. Chem. Commun. 2004, 86−87). This result strongly
supports our stereochemical assignments of (S,S)-28 and (R,R)-28.
(17) Lohray, B. B.; Rao, B. S.; Baskaran, S.; Venkateswarlu, S.;
Bhushan, V. Indian J. Chem., Sect B 1998, 37, 209−218.
AUTHOR INFORMATION
(
(
18) Plate, M.; Overs, M.; Schaefer, H. J. Synthesis 1998, 1255−1258.
19) Greene, T. W.; Wuts, P. G. M. Protecting Groups in Organic
■
Corresponding Author
E-mail: j.devoss@uq.edu.au.
Synthesis, 3rd ed.; Wiley: New York, 1999.
20) Coutrot, P.; Grison, C.; Bomont, C. J. Organomet. Chem. 1999,
*
(
Notes
5
86, 208−217.
The authors declare no competing financial interest.
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24) Banfi, L.; Cabri, W.; Poli, G.; Potenza, D.; Scolastico, C. J. Org.
ACKNOWLEDGMENTS
■
(
(
We are grateful for Australian Postgraduate Award scholarship
support for A.A.S. and to Thelma Peek (Queensland
Department of Primary Industries and Fisheries) and Dr.
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dx.doi.org/10.1021/jo500791y | J. Org. Chem. XXXX, XXX, XXX−XXX