Total synthesis of epothilone D: The nerol/macroaldolization approach

Article abstract of DOI:10.1021/jo401355r

A highly convergent and stereocontrolled synthesis of epothilone D (4) is reported. Key features are a cheap and Z-selective synthesis of the northern half based on nerol and acetoacetate and chromium(II)-mediated Reformatsky reactions as a powerful tool for chemoselective asymmetric carbon-carbon bond formations, including an unusual stereospecific macroaldolization.

Full text of DOI:10.1021/jo401355r

Subscriber access provided by HARVARD UNIVERSITY
Article
Total Synthesis of Epothilone D: the Nerol/Macroaldolization Approach
Ludger Wessjohann, Günther O Scheid, Uwe Eichelberger, and Sumaira Umbreen
J. Org. Chem., Just Accepted Manuscript • Publication Date (Web): 30 Sep 2013
Downloaded from http://pubs.acs.org on October 2, 2013
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a free service to the research community to expedite the
dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts
appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been
fully peer reviewed, but should not be considered the official version of record. They are accessible to all
readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered
to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published
in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just
Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor
changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers
and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors
or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
The Journal of Organic Chemistry is published by the American Chemical Society.
1155 Sixteenth Street N.W., Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 30
The Journal of Organic Chemistry
1
2
3
4
5
Total Synthesis of Epothilone D:
6
7
8
9
the Nerol/Macroaldolization Approach
Ludger A. Wessjohann*†, Günther O. Scheid†, Uwe Eichelberger and Sumaira Umbreen
Department of Bioorganic Chemistry, LeibnizꢀInstitute of Plant Biochemistry, Weinberg 3,
Dꢀ06120 Halle (Saale) Germany
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
*Corresponding author: Tel: +49 345 5582 1301; fax: +49 345 5582 1301; email:
wessjohann@ipbꢀhalle.de
Table of Contents/Abstract Graphic
S
N
S
Cr-mediated
Reformatsky
Macrocyclization
O
OH
N
Br
O
O
O
OH
O
O
OTBSO
Epothilone D
Abstract: A highly convergent and stereocontrolled synthesis of epothilone D (4) is reported.
Key features are a cheap and Zꢀselective synthesis of the northern half based on nerol and
acetoacetate, and chromium(II)ꢀmediated Reformatsky reactions as a powerful tool for
chemoselective asymmetric carbonꢀcarbon bond formations including an unusual stereospecific
macroaldolization.
Footnote:
†part of this work was performed at the Vrije University Amsterdam, NL
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 2 of 30
1
2
3
4
Introduction
5
6
7
8
Epothilones are cytotoxic macrolides, first isolated by Höfle and coꢀworkers from
myxobacterium Sorangium cellulosum strain 90.1 After the elucidation of the absolute
stereochemistry of epothilone B (2) through a combination of Xꢀray crystallography and
chemical degradation studies, various epothilones were discovered and eventually developed into
marketed drugs. The high potency of epothilones against cancer cells results from their ability to
intervene in tubulin polymerisation dynamics in which they stabilize formed microtubuli.2 These
are part of the cytoskeleton and are indespensible for cell division.3 Several total and many partial
syntheses of epothilones (Figure 1) using different strategies have been published.4 However,
new syntheses are still in demand as they can give easier access, allow new derivatives, or can be
cheaper and provide freedom to operate, e.g. for generics production.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
In comparison to the wellꢀknown Taxotere® and Taxol® (paclitaxel),5 which are frontline
anticancer agents, epothilones exhibit several important advantages. Some epothilones are
available by fermentation with (genetically engineered) bacteria.6 Furthermore, epothilones
possess unique pharmacokinetic profiles and show activity against paclitaxel resistant cell lines.
Mechanistic investigations show that they competitively bind to the same pocket of βꢀtubulin as
taxol.7 This was confirmed by comparison of structural data of the tubulin polymer complexed to
either taxol or epothilone A or B.8 However, taxanes and epothilones each occupy the binding
pocket in a unique and independent manner, which revokes the idea of a common pharmacophore
for epothilones and taxol. Although epothilones have a microtubuleꢀstabilizing mechanism of
action similar to taxanes, they express nonꢀoverlapping mechanisms of resistance.9 Therefore
they were approved by the U.S. Food and Drug Administration for the treatment of taxane and
anthracycline resistant breast cancer in 2007.10
ACS Paragon Plus Environment

Page 3 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
R
X
R1
northern
S
N
OH
7
8
9
O
southern
half
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
O
OH O
1 Epothilone A, R = H, R1 = H, X = O
2 Epothilone B, R = Me, R1 = H, X = O
3 Epothilone C, R = H, R1 = H, X = bond
4 Epothilone D, R = Me, R1 = H, X = bond
5 Epothilone E, R = H, R1 = H, X = O
6 Epothilone F, R = Me, R1 = OH, X = O
Figure 1. Structures of epothilones A–F.
Structureꢀactivity relationships (SAR) of various epothilone analogues suggest that epothilones
may not tolerate too many broad structural changes.11 This renders access to the natural
compound crucial. At first glance the arrangement of the functional groups in the macrocycle
allows a variety of retrosynthetic disconnections. The majority of reports on epothilone syntheses
follow very similar synthetic strategies. Often reꢀoccuring features are the introduction of the
thiazole sideꢀchain via a Wittig reaction,4n aldol connection of carbon atoms C6 and C7, and the
Yamaguchi macrocyclization for the construction of the macrolactone scaffold.
Results and Discussion
The retrosynthetic strategy to epothilone D (4) reported herein initially follows the classical
northernꢀsouthern half strategy. The crucial step, however, is the unusal formation of C6–C7
bond via a novel chromiumꢀReformatskyꢀmacrocyclization of the linear epothilone precursor 7
(Scheme 1).
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 4 of 30
1
2
3
4
5
6
S
21
8
16
20
7
6
OH
14
N
18
Chromium
Reformatsky
3
O
7
8
9
O
OH O
4
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
S
O
N
Br
O
Esterification
O
OR O
7
Chromium
Reformatsky
Wittig
S
N
Br
12
14
8
HO
7
OTBS
+
O
OR O
OH
Alkylation-
decarboxylation
9
8
Ph
O
O
6
2
3
15
+
1
O
N
12
+
16
Br
OtBu
7
14
O
O
Br
O
OAc
O
10
11
13
12
Scheme 1. Retrosynthetic analysis of epothilone D (4)
This chromiumꢀmediated version of an aldolꢀreaction exhibits extraordinary chemoꢀ and
diastereoselectivity.4g,12 The behavior of chromium(III) enolates was thoroughly studied in our
group, and thus we expected the reaction to provide the desired synꢀaldol product (C6/C7)
exclusively in combination with the correct antiꢀCramꢀselectivity (C7/C8).12
The other disconnections cut the ester moiety in compound 7, which separates the epothilones
northern and southern halves (8 and 9, respectively). Further disconnection of compound 8
through a Wittigꢀreaction and alkylationꢀdecarboxylation sequence leads back to acetoacetate 10
and the neryl backbone 11. Retrosynthesis of the southern half (i.e. 9) leads to a scission at C2–
ACS Paragon Plus Environment

Page 5 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
C3, leading to bromo acetimide 12 and keto aldehyde 13, featuring another (auxiliary controlled)
chromiumꢀReformatsky reaction.
7
8
9
Commencing with the forward synthesis of the northern half (Scheme 2), oxidative
acetoxylation of acetoacetate 10 was achieved via the bromination of tertꢀbutyl acetoacetate with
NBS followed by a nucleophilic substitution with sodium acetate giving compound 10 in 68%
yield.13 Later this twoꢀstep process was reduced to a one pot procedure, using elementary
bromine in the presence of a sodium alkanoate. With tertꢀbutyl acetoacetate and sodium acetate
product 10 was obtained directly in 80% yield.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Deprotonation of 10 with NaH and subsequent alkylation with neryl bromide (11) gives the
quaternary acetoacetateꢀderivative 14 in 96% to quantitative yield.
For the introduction of the terminal hydroxylꢀgroup, Sharpless allylicꢀoxidation with tꢀBuOOH
and (usually 5%) catalytic SeO2 was used.14 Although the catalytic version is lower yielding than
the overstoichiometric use of SeO2, up to date it is still the only method that allows a
regioselective catalytic oxidation of the terminal Eꢀmethyl group. The catalytic version provides a
maximum yield of 44% of C7ꢀoxidized products (15), but requires only 1.75 mol% of selenium
dioxide. The catalytic process has the better overall performance, because starting material is
readily synthesized in large amounts, unreacted material can be recovered if desired, and most
importantly, the carryover of selenium residues is avoided. These were found to be detrimental
even at very low concentration for the subsequent catalytic hydrogenation.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 6 of 30
1
2
3
4
5
6
7
8
9
NaH
neryl bromide
O
O
O
O
12
100 bar H2
[Ru{(S)-BINAP}(OAc)2]
(11)
Br2, NaOAc
DMF, 80%
O
O
OtBu
OtBu
8
8
15
15
OH
7
DMF, 96%
MeOH/H2O
89% (8S:8R= 81:19)
OAc
t
t
AcO CO2 Bu
AcO CO2 Bu
X
10
cat. SeO2, tBuOOH
14: X = H
15: X = OH
16
CH2Cl2, 45%
TFA
CH2Cl2
75%
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
21
S
17
PBu3Cl
N
12
S
O
TBSCl, Et3N
O
NaHMDS
15
OTBS
OTBS
15
7
OH
N
THF, _63 °C
96%
cat. DMAP
CH2Cl2, 80%
17
OR
OR
OAc
17
18: R = Ac
19: R = H
K2CO3
MeOH
72%
22: R = (R)-C(O)CH(OMe)Ph
8: R = OH
K2CO3, MeOH, 97%
OMe
Ph
(R)-α-PhCH(MeO)COOH, EDCI
cat. DMAP, CH2Cl2, 80%
20: R =
O
Scheme 2. Synthesis of northern half (showing resolution of Oꢀmethyl mandelates)
Hydrogenation of the C8–C9 double bond of allylic alcohol 15 utilizing Noyoriꢀcatalyst
[Ru{(S)ꢀBINAP}(OAc)2] (1.5 mol%) in methanolꢀwater (95:5) at >100 bar hydrogen pressure led
exclusively to the reduction of the C8–C9 double bond,15 yielding compound 16 (89%). The
regioselectivity results on one hand from the coordination of the allylic ωꢀhydroxy group to the
catalyst. On the other hand, and most importantly, competing hydrogenation of the C12–C13
double bond is prevented by the bulky residues at the quaternary C15 that probably hampers the
catalyst to dock to surrounding potential ligand positions. Without the bulky substituents, the
hydrogenation gives mixtures (saturation of double bonds C8–C9 or C12–C13 or both). The
1
enantiomeric ratio was determined by H NMR analysis of the C8 protons of both Rꢀ and Sꢀ
Mosher ester of compound 16. The ratio between 8S:8R is 81:19 in average. A separation of the
enantiomeric impurity is not required as a later stereoselective reaction exclusively reacts with
the desired 8Sꢀisomer (vide infra). The absolute stereochemistry at C8 was confirmed by
comparison with the Mosher ester of original northern half (courtesy of Prof. Höfle), obtained by
degradation of natural epothilone. Acidic decarboxylation of 16 using TFA takes place without
ACS Paragon Plus Environment

Page 7 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
detectable isomerization of the remaining double bond, in contrast to classic Krapcho
decarboxylation conditions. The tradeꢀin, however, is a partial trifluoroacetylation of the ωꢀ
alcohol, which can be reverted quantitatively by work up with aqueous NaHCO3.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
The obtained free primary alcohol 17 was subsequently protected as TBSꢀether 18, both present
as inseparable diastereomers. The distant and independent stereocenter at C15 therefore requires
enantioselective separation. One possibility is the transesterification of acetate 18 with (R)ꢀαꢀ
methoxyphenylacetic acid which allows the separation of the resulting diastereomers with
standard chromatography (40% isolated yield, 80% based on theory). Alternative methods to
obtain the correct diastereoisomer (20) are asymmetric synthesis applying Evans auxiliary, or
enzymatic resolution (e.g. by Candida antarctica lipase B).4e Since the C15 stereocenter of 20 is
in αꢀposition to a keto group, the undesired diastereomer can be racemized and reused. A
dynamic kinetic resolution therefore can be performed in a circular or phase separated system
without isolation of the undesired diastereomer, as has been reported elsewhere.16
Diastereomerically pure 20 was subjected to the Wittig olefination using thiazole phosphonium
salt 21 in the presence of NaHMDS yielding olefin 22 without racemization in excellent
yield.4n,17 Other ylids show worse reactivity or purification behavior.18 Finally, ester
saponification gave access to the northern half building block 8.
The stereoselective formation of C2–C3 aldol bond requires the chemoselective and
asymmetric transfer of a carboxymethyl unit, i.e. an "acetate Cαꢀanion” (ester enolate) to an
aldehyde (Scheme 1). This transformation can be achieved by an auxiliary controlled chromiumꢀ
Reformatsky reaction which allows βꢀinduction with soꢀcalled nonꢀEvans stereoselection,4e,4g,9,19
in contrast to lithium or other counter ions.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 8 of 30
1
2
3
4
5
6
7
8
9
In the presence of 2.2 equivalents of CrCl2, bromoacetate 12 reacts exclusively at the aldehyde
portion with βꢀketo aldehyde 13 to the desired product 23 (Scheme 3). In contrast to other
approaches to the southern half, the aldol product already has the correct oxidation state at C1.
This direct aldol reaction (without scavenging the aldolate) is only possible, because the
intermediate chromium(III) aldolates are insensitive to retroꢀaldolization. Retroaldolization is
commonly observed in sterically compressed nonꢀcyclic double aldolates like 23, which reꢀopen
at the C3ꢀC4 bond during reaction if, e.g. sodium or lithium aldolates would be the
intermediates.9 Please note, that in the final macrocycle the limited conformational freedom
allows a greater stability of the aldol portion, a fact that has been used by Danishefsky in his
macroaldolization approach.4k
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
13
Ph
CH2Br
Ph
O
O
2.2 eq. CrCl2,
O
N
O
N
Et
0.1 eq LiI,THF
76%
O
O
O
OR O
O
12
23: R = H
24: R = TBS
TBSOTf
2,6-lutidine, CH2Cl2, 93%
LiOH
H2O2
THF/H2O
90%
Br
HO
Et
PhNMe3Br3
THF, 98%
HO
O
OR
O
O
OR
O
9: R = TBS
25: R = TBS
Scheme 3. Synthesis of Southern half
The Nꢀacylation of the auxiliary with 2ꢀbromoacetyl bromide was also successfully
combined with the Reformatskyꢀreaction in a two step ꢀ one pot process. TBSꢀprotection of the
secondary alcohol 23 was followed by the cleavage of a chiral auxiliary to obtain carboxylic
ACS Paragon Plus Environment

Page 9 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
acid 25. The synthesis of the southern half was completed by a quantitative bromination of 25
at C6 and provides αꢀbromoketone 9. Several brominating agents worked on 24 or 25, but
phenyltrimethylammonium tribromide applied on free acid 25 was found to be the best choice.
In contrast to expectation, in 24 competing C2ꢀbromination was not a problem, but under the
basic auxiliary cleavage conditions, the formation of cyclic byproduct was observed.
Esterification of southern half carboxylic acid 9 with nothern half chiral alcohol 8 led to the
linear epothilone precursor 26 in 80% yield (Scheme 4). The primary TBSꢀether was then
selectively cleaved by treatment with 1Sꢀ(+)ꢀCSA to furnish alcohol 27 (91%).
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
8
+
9
S
N
EDCI, DMAP
CH2Cl2, 80%
8
R
15
Br
O
6
O
OTBSO
26: R = OTBS
27: R = OH
7: R = O
CSA, CH2Cl2/MeOH, 91%
Py·SO3, Et3N
DMSO, CH2Cl2, 88%
S
CrCl2
2.2 eq.
7
6
OH
N
7
O
0.1 eq. LiI
THF
36%
(29% abs)
O
OR O
28: R = TBS
4: R = H
TFA, CH2Cl2
79%
Scheme 4. Macrocyclization and completion of the synthesis
In a next step, alcohol 27 was converted to aldehyde 7 using a Doeringꢀoxidation. Deviation
from the reaction conditions or order of reagents, or other reactions such as Swern or Dess–
Martin oxidation gave lower yields, apart from other disadvantages.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 10 of 30
1
2
3
4
5
6
7
8
9
The linear macrocyclization precursor 7 was followed by a chromium(II)ꢀmediated
Reformatsky macrocyclization, the first one of its kind (Scheme 4) with challenging selectivity
demands. Required are synꢀselectivity at C6–C720 and antiꢀCram double stereo differentiation
between C7 and C821 and, ideally in such a way, that only the 8Sꢀdiastereomer (shown) is
reacting, and not the residual 20% 8Rꢀepimer (not shown). Induction for this selection must come
from the fully defined C3 or the C15 stereocenter. But not only stereoselection is crucial, also
chemoselectivity. Since C1 is an ester, and the C4ꢀdimethyl group exerts a strong ThorpeꢀIngold
effect, any C6ꢀenolate is bound to give a 6ꢀmembered ring Claisen product rather than a
macroaldol. Indeed, the latter reaction occurs with all other tested counterions (Li, Zn, In, Sm
etc.) different than chromium(III).
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Fortunately, the addition of compound 7 in THF via syringe pump to a suspension of CrCl2 and
LiI in THF furnished the desired product (22% based on available (8S)-7 as substrate) exclusively
as the correct diastereomer, i.e. with C6–C7ꢀsyn and C7–C8ꢀantiꢀCram configuration. The other
starting diastereomer did not cyclize to the epimeric epothilone within the reaction time, and was
not recovered. From the reaction mixture only compound 28 was isolated (see Experimental
Section) and its deprotection in the final step afforded epothilone D (4). NMR analysis confirmed
the structure of compound 4 by comparison to the natural product and literature values of
synthetic epothilone D (see Supporting Inormation page S52). Other spectroscopic and
chromatographic properties, and eventually the antimitotic activity on human and plant cells
proved to be identical.22
Also an inverted order for the connection of southern and northern half was successfully
performed, i.e. a C6–C7ꢀchromium aldol reaction with C1ꢀmethyl ester gave 97% yield of a
diastereomeric mixture, from which 60% of the correct diastereomer and precursor for a more
conventional order of construction was separated. After deꢀ and reprotection, a standard
ACS Paragon Plus Environment

Page 11 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
Yamaguchi macrolactonization used in many former syntheses gave the product after a final
deprotection. The intermolecular chromiumꢀReformatsky reaction expectedly gave much higher
yields than the cyclizing one, but this is counterbalanced by a lower selectivity towards the 8Sꢀ
isomer requiring a subsequent separation effort, and a lower yield of the macrolactonization vs.
the esterification. The macrolactonization variant also required additional protection/deprotection
steps. Thus despite higher yields in the C6–C7 aldol formation, of the macrolactonization
approach, the unusual chromium(II) mediated macrocyclizing Reformatsky variant provides less
purification effort, a better overall yield, and a reduced step count.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Conclusion
A highly convergent and stereocontrolled synthesis of epothilone D (4) is presented. Some
crucial steps to the major building blocks and the unusual chromium(II)ꢀmediated
macroaldolization variant are clearly distinct from other syntheses. The use of cheap, available
nerol avoids problems with C12–C13 cisꢀselectivity, enzymatic (or other) resolution of a cheap
2ꢀacetylꢀacetoacetate derivative gives perfect stereoselection at C15 (formally this is
diastereoselection, but there is no influence of the remote C8 center on the process, which thus
behaves like an enantioselection). The two chromiumꢀReformatsky steps provide the perfect
chemoꢀ and diastereoselectivity in two aldolizations which both fail with other counterions, one
of them being the first chromiumꢀmacroaldolization. In direct comparison with the
macrolactonization approach, the macroaldolization route provided a better overall performance
with respect to step count, separation effort and overall yield.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 12 of 30
1
2
3
4
Experimental Section
5
6
7
8
9
tert-Butyl-2-acetoxyacetoacetate (10). tertꢀButylꢀ2ꢀbromoꢀacetoacetate (59.27 g, 250 mmol)
was added dropwise to a suspension of sodium acetate (30.76 g, 375 mmol) in DMF (250 mL).
After stirring at ambient temperature for 90 min, water (415 mL) was added, followed by
extraction with ethyl acetate (3 × 325 mL). The combined organic layers were washed with water
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(3 × 325 mL) and brine (325 mL), dried over anhydrous Na2SO4 and after filtration, the solvent
was removed in vacuum. The resulting oil was purified via distillation (12 mbar, 128 °C; yield
1
36.52 g, 68%): H NMR (300 MHz, CDCl3) δ 1.50 (s, 9H), 2.22 (s, 3H), 2.34 (s, 3H), 5.40 (s,
1H); 13C NMR (APT, 75 MHz, CDCl3) δ (–) 20.5, (–) 27.3, (–) 27.8, (–) 78.4, (+) 84.0, (+) 163.1,
(+) 169.3, (+) 197.5; IR (KBr) 841 (w), 1094 (m), 1152 (s), 1221 (s), 1250 (s), 1395 (w), 1420
(w), 1456 (w), 1748 (s), 2938 (m), 2980 (m) cm–1; C10H16O5 (216.23, 216.10); MS (CI) m/z (%)
117 (19), 143 (12), 161 (100), 205 (43), 207 (12), 217 (18); HRMS (ESI) m/z [M + H]+ calcd
217.1076, found 217.1046.
Z-2-Acetoxy-2-acetyl-5,9-dimethyl-deca-4,8-dienoic-acid-tert-butyl ester (14). tertꢀButylꢀ
2ꢀacetoxyacetoacetate (10) (19.5 g, 90 mmol) was added dropwise to a stirred suspension of NaH
(2.59 g, 108 mmol) in THF (180 mL) at 0 °C. After the complete liberation of hydrogen gas,
nerylbromide (19.6 g, 90 mmol) was added dropwise at 0 °C. The solution was warmed to room
temperature and then allowed to stir for 16 h. The resulting mixture was diluted with ether
(750 mL), washed with water (3 × 200 mL), brine (1 × 200 mL), dried over anhydrous Na2SO4,
filtered and concentrated in vacuum. The crude product was used without further purification
1
(yield 30.3 g, 96%): H NMR (400 MHz, CDCl3) δ 1.43 (s, 9H), 1.58 (s, 3H), 1.65 (s, 3H), 1.67
(s, 3H), 1.90–2.05 (m, 4H), 2.16 (s, 3H), 2.28 (s, 3H), 2.75–2.90 (m, 2H), 4.95–5.09 (m, 2H); 13C
ACS Paragon Plus Environment

Page 13 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
NMR (100.5 MHz, CDCl3) δ 18.1, 21.1, 24.0, 28.1, 26.8, 26.9, 28.1, 32.4, 32.8, 83.8, 88.1, 116.5,
124.0, 132.0, 140.2, 166.1, 169.6, 201.0; IR (KBr) 845 (w), 1024 (w), 1072 (w), 1086 (w), 1115
(w), 1157 (s), 1236 (s), 1256 (s), 1314 (w), 1370 (s), 1389 (w), 1437 (w), 1452 (w), 1746 (s),
2861 (w), 2882 (w), 2932 (m), 2976 (m) cm–1; C20H32O5 (352.47, 352.22), MS (CI) m/z (%) 353
(13), 298 (21), 297 (100), 279 (14), 255 (10), 253 (13), 237 (27), 219 (20), 209 (65), 193 (10),
175 (6), 153 (7), 137 (16); HRMS (ESI) m/z [M + H]+ calcd 353.2328, found 353.2324.
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(4Z,8E)-2-Acetoxy-2-acetyl-5,9-dimehtyl-10-hydroxy-deca-4,8-dienoic-acid-tert-butyl
ester (15). Powdered seleniumdioxide (0.16 g, 1.42 mmol) was suspended in CH2Cl2 (50 mL),
followed by the addition of 70% tertꢀbutylhydroperoxide solution (10.2 g, 79.5 mmol). The
resulting mixture was stirred at room temperature for 30 min and then treated with compound 14
(10.0 g, 28.4 mmol). The reaction mixture was stirred for further 48 h and then concentrated
under reduced pressure. Toluene (3 × 50 mL) was added to it and subsequently removed in
vacuum (for the removal of excess tertꢀbutylhydroperoxide). Slightly yellow oil was obtained
1
and purified by flash chromatography (ethyl acetate/petroleum ether, 1:2; yield 4.65 g, 44%): H
NMR (300 MHz, CDCl3) δ 1.45 (s, 9H), 1.67 (s, 3H), 1.71 (s, 3H), 1.90–2.15 (m, 4H), 2.16 (s,
13
3H), 2.31 (s, 3H), 2.85–2.88 (m, 2H), 3.99 (s, 2H), 5.01−5.03 (m, 1H), 5.36−5.38 (m, 1H); C
NMR (75.5 MHz, CDCl3) δ 13.7, 20.8, 23.5, 25.8, 27.1, 27.8, 31.6, 32.3, 68.7, 83.2, 87.9, 116.5,
124.8, 135.2, 139.5, 165.8, 169.4, 201.2; IR (KBr) 755 (w), 845 (w), 1018 (w), 1049 (w), 1072
(w), 1157 (m), 1236 (m), 1258 (m), 1371 (m), 1395 (w), 1435 (w), 1456 (w), 1742 (s), 2854 (w),
2934 (w), 2978 (w) cm–1; C20H32O6 (368.46, 368.22), MS (CI) m/z (%) 369 (6), 329 (6), 311 (26),
295 (100), 271 (11), 253 (24), 235 (14), 203 (10), 169 (9), 135 (10); HRMS (ESI) m/z [M + H]+
calcd 369.2277, found 369.2288.
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 14 of 30
1
2
3
4
Z-(9S)-2-Acetoxy-2-acetyl-5,9-dimethyl-10-hydroxy-deca-4-enoic-acid-tert-butyl
ester
5
6
7
8
(16). Compound 15 (7.94 g, 21.6 mmol) was dissolved in a mixture of absolute methanol
(15.0 mL) and water (750 ꢁL). The solution was degassed with three freezeꢀthawꢀcycles before
the addition of [Ru{(S)ꢀBINAP}(OAc)2] (185 mg, 1 mol%) and then placed in an autoclave
under nitrogen atmosphere together with a magnetic stirring bar. After threefold purging with
hydrogen (5.0 quality) the autoclave was set under a pressure of 100 bar hydrogen (5.0 quality)
and stirred at room temperature for 22 h. The hydrogen pressure was carefully released and the
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
solution was concentrated in vacuum to yield brown oil which was purified by flash
25
D
chromatography (ethyl acetate/petroleum ether, 1:2; yield 7.08 g, 88%):
[α
]
= −5.2° (c = 0.62,
1
CHCl3); H NMR (300 MHz, CDCl3)
δ 0.91 (d, 3H, J = 6.4 Hz), 1.24–1.27 (m, 2H), 1.33–1.42
(m, 2H), 1.45 (s, 9H), 1.55–1.66 (m, 1H), 1.68 (s, 3H), 1.99–2.03 (m, 2H), 2.16 (s, 3H), 2.31 (s,
3H), 2.56–2.95 (m, 2H), 3.41 (dd, 1H,
J
= 6.3 Hz, 10.5 Hz), 3.49 (dd, 1H,
J = 5.9 Hz, 10.5 Hz),
13
5.00 (t, 1H,
J
= 6.0 Hz); C NMR (75.5 MHz, CDCl3)
δ
16.6, 20.8, 23.6, 25.2, 27.1, 27.8, 32.0,
32.3, 32.9, 35.7, 68.2, 83.2, 87.9, 116.0, 140.2, 165.7, 169.4, 201.1; IR (KBr) 756 (w), 845 (w),
1045 (m), 1065 (m), 1080 (m), 1157 (s), 1235 (s), 1258 (s), 1371 (s), 1395 (w), 1429 (w), 1456
(w), 1744 (s), 2874 (w), 2934 (m), 2972 (m) cm–1; C20H34O6 (370.48, 370.24), MS (CI)
m/
z
(%) 369 (6); HRMS (ESI)
m/z
[M + H]+ calcd 371.2433, found 371.2420.
Z-(10S)-3-Acetoxy-11-hydroxy-6,10-dimethyl-5-undecen-2-one (17). TFA (2.80 mL) was
added dropwise to a solution of compound 16 (1.03 g, 2.79 mmol) in CH2Cl2 (28 mL) and
allowed to stir for 2 h at room temperature. After completion of reaction all volatile matter was
removed in vacuum and the remaining oil was dissolved in methanol (28 mL). Saturated
NaHCO3 solution (5.6 mL) was added to the reaction mixture and the suspension was stirred for
140 min at ambient temperature followed by dilution with ether (200 mL). The organic layer was
ACS Paragon Plus Environment

Page 15 of 30
The Journal of Organic Chemistry
1
2
3
4
separated, washed with water (2 × 50 mL), brine (50 mL) and dried over anhydrous Na2SO4.
5
6
Filtration and removal of the solvents in vacuum gave slightly yellow oil which was purified by
7
22
D
8
9
flash chromatography (ethyl acetate/petroleum ether, 2:3; yield 568 mg, 75%):
[α
]
= −4.95° (c
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
1
= 0.48, CHCl3); H NMR (300 MHz, CDCl3)
δ 0.92 (d, 3H, J = 6.6 Hz), 1.24–1.27 (m, 2H),
1.33–1.42 (m, 2H), 1.55–1.67 (m, 1H), 1.70 (s, 3H), 1.99–2.03 (m, 2H), 2.14 (s, 3H), 2.16 (s,
= 6.0 Hz); 13C
3H), 2.46–2.50 (m, 2H), 3.44–3.49 (m, 2H), 5.11 (t, 1H,
J
NMR (75.5 MHz, CDCl3)
δ 16.6, 20.8, 23.5, 25.2, 26.8, 29.1, 32.1, 33.0, 35.7, 68.2, 78.5, 117.7,
139.6, 170.4, 205.2; IR (KBr) 755 (w), 986 (w), 1047 (m), 1175 (w), 1242 (s), 1375 (m), 1435
(w), 1456 (w), 1730 (s), 1744 (s), 2872 (m), 2932 (s) cm–1; C15H26O4 (270.36, 270.18), MS (ESIꢀ
MS)
Z-(10S)-3-Acetoxy-11-tert-butyldimethylsilyloxy-6,10-dimethyl-5-undecen-2-one
m/z
(%) 563.3 (100) [2M + Na]+, 293.0 (54) [M + Na]+, 271.1 (7) [M + H]+.
(18).
Triethylamine (541 ꢁL, 3.90 mmol) and 4ꢀdimethylaminopyridine (DMAP, 12 mg, 0.10 mmol)
were added to a solution of compound 17 (528 mg, 1.95 mmol) in absolute CH2Cl2 (10.0 mL).
The mixture was cooled to 0 °C and stirred for 5 min at this temperature. TBDMSCl (368 mg,
2.44 mmol) was added to it and the solution was stirred over night at room temperature. After
completion of reaction, methanol (460 ꢁL) was added to the reaction mixture and was allowed to
stir for another 30 min. All solvents were removed under reduced pressure, and the resulting
residue was suspended in ether (15 mL) and saturated NH4Cl solution (15 mL). The organic layer
was separated and the aqueous layer was extracted with ether (2 × 10 mL). The combined organic
layers were washed with brine (15 mL), dried over anhydrous Na2SO4, filtered and concentrated
in vacuum to yield an oil which was purified by flash chromatography (ethyl acetate/petroleum
25
D
1
ether, 1:10; yield 597 mg, 80%):
0.00 (s, 6H), 0.83 (d, 3H,
[α
]
= −2.38° (c = 0.68, CHCl3); H NMR (300 MHz, CDCl3)
δ
J
= 6.4 Hz), 0.86 (s, 9H), 0.94–1.07 (m, 1H), 1.20–1.42 (m, 3H),
57
58
59
60
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 16 of 30
1
2
3
4
1.46–1.58 (m, 1H), 1.66 (s, 3H), 1.89–2.01 (m, 2H), 2.10 (s, 3H), 2.12 (s, 3H), 2.38–2.47 (m,
5
6
2H), 3.33 (dd, 1H,
J
= 6.4 Hz, 9.8 Hz), 3.39 (dd, 1H,
J
= 6.0 Hz, 10 Hz), 4.94 (t, 1H,
J = 6.4 Hz),
7
8
9
5.03–5.07 (m, 1H); 13C NMR (75.5 MHz, CDCl3)
δ
–5.2, 16.8, 18.4, 20.8, 23.5, 25.3, 26.0, 26.7,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
29.0, 32.2, 33.1, 35.8, 68.3, 78.5, 117.6, 139.7, 170.3, 205.0; IR (KBr) 775 (m), 837 (m), 1053
(w), 1092 (m), 1248 (s), 1373 (w), 1458 (w), 1472 (w), 1734 (s), 1748 (s), 2857 (m), 2891 (w),
2905 (w), 2932 (m), 2955 (m) cm–1; C21H40O4Si (384.63, 384.27), MS (CI)
m/
z
(%) 385 (13) [M
[M + H]+
+ H]+, 327 (13), 267 (26), 253 (6), 193 (40), 175 (62), 117 (100). HRMS (ESI)
calcd 385.2774, found 385.2785.
m/z
Z-(10S)-11-(tert-Butyldimethylsilyloxy)-3-hydroxy-6,10-dimethyl-5-undecen-2-one (19).
Saturated potassium carbonate solution (400 ꢁL) was added to a solution of compound 18 (1.94
g, 5.05 mmol) in methanol (20.0 mL) and allowed to stir for 14 min at ambient temperature.
After completion of reaction the solvent was removed under reduced pressure and extracted with
diethylether (5 × 30 mL), washed with brine (30 mL) and dried over anhydrous Na2SO4. After
filtration and removal of the solvent in vacuum, the remaining oil was purified via flash
25
D
chromatography (ethyl acetate/petroleum ether, 1:4; yield 1.69 g, 97%):
CHCl3); 1H NMR (300 MHz, CDCl3)
[α
]
= −2.13°(c = 0.72,
δ
0.04 (s, 6H), 0.87 (d, 3H,
J
= 6.4 Hz), 0.89 (s, 9H), 1.00–
1.65 (m, 5H), 1.70 (s, 3H), 1.96–2.04 (m, 2H), 2.19 (s, 3H), 2.34–2.41 (m, 1H), 2.52–2.58 (m,
13
1H), 3.30–3.44 (m, 2H), 4.19–4.23 (m, 1H), 5.08–5.11 (m, 1H); C NMR (APT, 75.5 MHz,
CDCl3)
δ (−) −5.2, (−) 16.8, (+) 18.4, (−) 23.6, (+) 25.4, (−) 25.6, (−) 26.0, (+) 32.1, (+) 32.3, (+)
33.1, (−) 35.7, (+) 68.3, (−) 76.7, (−) 117.9, (+) 139.6, (+) 209.4; IR (KBr) 667 (w), 775 (m),
837 (s), 1006 (w), 1093 (s), 1147 (w), 1163 (w), 1249 (s), 1362 (m), 1373 (m), 1387 (w),
1419 (w), 1436 (w), 1457 (m), 1464 (m), 1472 (m), 1653 (w), 1684 (w), 1700 (w), 1733 (s),
ACS Paragon Plus Environment

Page 17 of 30
The Journal of Organic Chemistry
1
2
3
4
5
1747 (s), 2855 (m), 2881 (w), 2902 (m), 2907 (m), 2929 (m), 2950 (m), 2956 (m) cm–1;
C19H38O3Si (342.59, 342.26), HRMS: [M+H]+ calcd. 342.2590, found 342.2583.
6
7
8
9
(R)-
dimethylnon-3-enyl ester (20). (1ꢀEthylꢀ3ꢀ(3ꢀdimethylaminopropyl)carbodiimide) (EDCI,
2.70 g, 14.09 mmol) was added to a solution of compound 19 (2.41 g, 7.04 mmol), ( )ꢀαꢀ
α-Methoxyphenylacetic acid Z-(1S,8S)-1-acetyl-9-(tert-butyldimethylsilyloxy)-4,8-
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
R
methoxyphenylacetic acid (1.28 g, 7.75 mmol) and DMAP (86 mg, 0.70 mmol) in CH2Cl2
(72.0 mL). The reaction mixture was allowed to stir for 2 h at ambient temperature followed by
the extraction with diethylether (250 mL), washing with water (2 × 100 mL) and brine (100 mL).
The organic layer was dried over anhydrous Na2SO4, filtered and concentrated under reduced
pressure. The remaining yellow oil contained two diastereomeric esters, which were separated by
flash chromatography (ethyl acetate/petroleum ether, 1:10; yield of the desired diastereomer:
25
D
1
2.796 g, 81%):
[α
]
= −28.54° (c = 0.51, CHCl3); H NMR (400 MHz, CDCl3) δ 0.01 (s, 6H),
0.83 (d, 3H, = 6.8 Hz), 0.86 (s, 9H), 1.12–1.62 (m, 5H), 1.52 (s, 3H), 1.84–2.01 (m, 2H), 2.07
J
(s, 3H), 2.25–2.45 (m, 2H), 3.35–3.39 (m, 2H), 3.41 (s, 3H), 4.35 (s, 1H), 4.93–5.30 (m, 2H),
7.35–7.49 (m, 5H). 13C NMR (75.5 MHz, CDCl3)
δ
–5.2, 16.8, 18.4, 23.4, 25.3, 26.0, 26.6, 29.2,
32.1, 33.1, 35.7, 57.5, 68.3, 79.0, 82.2, 117.3, 127.1, 128.5, 128.7, 135.8, 139.7, 170.1, 204.3; IR
(KBr): 665 (w), 697 (w),733 (w), 756 (w), 776 (m), 814 (w), 837 (s), 916 (w), 939 (w), 1005 (w),
1032 (w), 1043 (w), 1098 (s), 1114 (s), 1171 (s), 1200 (m), 1254 (m), 1388 (m), 1459 (m),
1470 (m), 1731 (s), 1757 (s), 2855 (m), 2897 (m), 2929 (s), 2952 (s) cm–1; C28H46O5Si (490.75,
490.31), HRMS (ESI)
(R)- -Methoxyphenylacetic acid Z-(1S,8S)-9-(tert-butyldimethylsilyloxy)-4,8-dimethyl-1-
[E-1-methyl-2-(2-methylthiazol-4-yl)-vinyl]-non-3-enyl ester (22). Sodium
m/z
[M + H]+ calcd 490.3115, found 490.3107.
α
hexamethyldisilazide (2 M solution in THF, 1.56 mL, 3.12 mmol) was added dropwise to a
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 18 of 30
1
2
3
4
5
6
7
8
9
cooled solution of tributylꢀ(2ꢀmethylthiazolꢀ4ꢀylmethyl)ꢀphosphonium chloride (21, 1.02 g,
2.92 mmol) in abs. THF (19.0 mL) at –65 °C. After stirring for 10 min, a solution of compound
22 (1.19 g, 2.43 mmol) in abs. THF (8.0 mL) was added slowly and then allowed to stir for 60
min at –65 °C. A saturated NH4Cl solution (45 mL) was added to the reaction mixture and
extracted with ether (5 × 25 mL). The combined organic extracts were washed with water (3 ×
30 mL), brine (1 × 50 mL), dried over anhydrous Na2SO4, filtered and then concentrated under
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
reduced pressure. The crude product was purified by flash chromatography (ethyl
25
acetate/petroleum ether, 1:5; yield 1.37 g, 96%):
NMR (250 MHz, CDCl3) 0.04 (s, 6H), 0.84 (d, 3H,
7H), 1.51 (s, 3H), 2.05 (s, 3H), 2.29 (t, 2H, = 7.2 Hz), 2.70 (s, 3H), 3.30–3.46 (m, 2H), 3.41 (s,
[α
]
= −27.6° (c
= 1.0, CHCl3); 1H
D
δ
J = 6.9 Hz), 0.89 (s, 9H), 0.95–2.05 (m,
J
3H), 4.75–4.80 (m, 1H), 4.78 (s, 1H), 5.25 (t, 1H,
J
= 6.6 Hz), 6.48 (s, 1H), 6.90 (s, 1H), 7.32–
(−) −5.3, (−) 14.9, (−)
13
7.37 (m, 3H), 7.43–7.46 (m, 2H); C NMR (APT, 100.5 MHz, CDCl3)
δ
16.7, (+) 18.4, (−) 19.2, (−) 23.3, (+) 25.2, (−) 25.9, (+) 31.5, (+) 32.1, (+) 33.0, (−) 35.7, (−)
57.3, (+) 68.3, (−) 79.7, (−) 82.6, (−) 116.3, (−) 118.9, (−) 120.4, (−) 127.2, (−) 128.5, (−) 128.4,
(+) 136.4, (+) 137.2, (+) 138.5, (+) 152.5, (+) 164.6, (+) 169.9; IR (KBr) 665 (w), 697 (w), 757
(s), 774 (m), 837 (s), 1006 (w), 1032 (w), 1040 (w), 1098 (s), 1112 (s), 1153 (m), 1177 (s), 1198
(m), 1253 (m), 1340 (w), 1361 (w), 1375 (w), 1388 (w), 1459 (m), 1470 (m), 1497 (w), 1751 (s),
2855 (m), 2928 (s), 2952 (s) cm–1; C33H51NO4Ssi (585.91, 585.33), HRMS (ESI)
calcd 586.3390, found 586.3381.
m/z
[M + H]+
(1E,5Z,3S,10S)-11-(tert-Butyldimethylsilyloxy)-2,6,10-trimethyl-1-(2-methylthiazol-4-yl)-
undeca-1,5-dien-3-ol (8). K2CO3 (0.28 g, 2.00 mmol) was added to a solution of compound 22
(0.59 g, 1.00 mmol) in methanol (10.0 mL) at ambient temperature. The reaction mixture was
stirred for 90 min at room temperature and then solvents were removed in vacuum. The residue
ACS Paragon Plus Environment

Page 19 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
was dissolved in ethyl acetate (40 mL) and washed with water (3 × 10 mL), brine (10 mL), dried
over anhydrous Na2SO4, filtered and then concentrated under reduced pressure. The slightly
yellow oil residue was purified by flash chromatography (ethyl acetate/petroleum ether, 1:3; yield
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
25
D
1
0.31 g, 70%):
0.86 (d, 3H,
[
α
]
= −11.14° (
c
= 0.95, CHCl3); H NMR (300 MHz, CDCl3)
δ 0.03 (s, 6H),
J
= 6.7 Hz,), 0.89 (s, 9H), 1.00–1.65 (m, 5H), 1.71 (s, 3H), 2.01−2.08 (m, 2H), 2.05
(s, 3H), 2.34−2.36 (m, 2H), 2.71 (s, 3H), 3.35 (dd, 1H,
J = 6.5 Hz, 9.7 Hz), 3.44 (dd, 1H, J =
5.9 Hz, 9.7 Hz), 4.13−4.15 (m, 1H), 5.15−5.17 (m, 1H), 6.56 (s, 1H), 6.94 (s, 1H); 13C
NMR (APT, 75.5 MHz, CDCl3)
δ (−) −5.4, (−) 14.4, (−) 16.8, (+) 18.3, (−) 19.1, (−) 23.6, (+)
25.5, (−) 25.9, (+) 32.3, (+) 33.1, (+) 34.1, (−) 35.7, (+) 68.3, (−) 77.2, (−) 115.4, (−) 118.8, (−)
120.1, (+) 139.3, (+) 141.7, (+) 152.9, (+) 164.4; IR (KBr) 775 (s), 837 (s), 1007 (w), 1053 (m),
1092 (s), 148 (w), 1186 (w), 1254 (m), 1362 (w), 1375 (w), 1387 (w), 1420 (w), 1437 (w), 1462
(m), 1472 (m), 1507 (m), 2857 (s), 2899 (s), 2928 (s), 2953 (s) cm–1; C24H43NO2SSi (437.75,
437.28), MS (CI)
m
/
z
(%) 438 (13) [M + H]+, 420 (27), 396 (4), 380 (12), 364 (4), 259 (27), 213
m/z
[M + Na]+ calcd 460.268, found 460.2676.
(100); HRMS (ESI)
(4S)-3-[3S-4,4-Dimethyl-1,5-dioxo-3-hydroxyheptyl]-4-benzyl-oxazolidin-2-on (23).
butyllithium solution (1.6 M, 9 mL, 14.4 mmol) was added dropwise at –63 °C to a solution of
)ꢀ4ꢀbenzyloxazolidinꢀ2ꢀon (2.55 g, 14.4 mmol) in 50 mL THF. The reaction mixture was
A
(S
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
further treated with bromoacetyl bromide (1.25 mL, 14.4 mmol), stirred for 30 min at –63 °C and
then allowed to come to room temperature. To this reaction mixture were added 2,2ꢀdimethylꢀ3ꢀ
oxopentanal (2.03 g, 15.8 mmol), CrCl2 (4.42 g, 36 mmol) and LiI (0.19 g, 1.44 mmol) under
argon. The mixture was stirred for 8 h at ambient temperature and after addition of brine (20 mL)
it was vigorously stirred for additional 15 min. The organic phase was separated and the aqueous
phase was extracted with Et2O (3 × 30 mL). The combined organic extracts were dried over
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 20 of 30
1
2
3
4
anhydrous MgSO4, filtered and concentrated under reduced pressure to provide dark oil which
5
6
was purified by flash chromatography (ethyl acetate/petroleum ether, 1:1; yield 3.8 g, 76%):
7
8
9
22
D
[
α
]
= +13.6°
;
1H NMR (300 MHz, CDCl3)
= 1.5 Hz, 7.2 Hz), 2.79 (dd, 1H, J
δ
1.04 (t, 3H,
J = 7.2 Hz), 1.16 (s, 3H), 1.26 (s, 3H),
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
2.57 (dq, 2H,
J
= 9.5 Hz, 13.4 Hz), 3.04–3.07 (m, 2H), 3.28–
3.33 (m, 2H), 4.18–4.24 (m, 2H), 4.35 (ddd, 1H,
J
= 1.2 Hz, 5.6 Hz), 4.66–4.74 (m, 1H), 7.20–
13
7.36 (m, 5H); C NMR (62.5 MHz, CDCl3)
δ
7.9, 19.6, 21.4, 31.2, 37.7, 38.1, 51.2, 55.2, 66.3,
72.6, 127.4, 129.0, 129.4, 135,1, 153.5, 172.6, 216.2; IR (KBr) 3522 (br), 3063 (w), 3029 (w),
2976 (w), 2938 (w), 2879 (w), 1783 (s), 1700 (s), 1498 (w), 1471 (w), 1454 (w), 1390 (m) 1354
(w), 1294 (w), 1213 (m), 1199 (m), 1111 (w), 1100 (w), 1076 (w), 1053 (w), 973 (w), 762 (w),
704 (w) cm–1; C19H25NO5 (347.41, 347.17), MS (ESIꢀMS): m/z (%) 348 (5) [M + H]+, 329 (24),
273 (56), 248 (24), 178 (85), 153 (14), 117 (34), 100 (68), 96 (100). HRMS (ESI)
calcd 347.1733, found 347.1728.
m/z
[M + H]+
(4S)-3-[3S-4,4-Dimethyl-1,5-dioxo-3-(tert-butyl-dimethylsilanyloxy)-heptyl]-4-benzyl-
oxazolidin-2-on (24). 2,6ꢀLutidin (1.11 mL, 9.5 mmol) and TBSOTf (1.49 mL, 6.48 mmol) were
added to a cooled solution of compound 23 (1.5 g, 4.32 mmol) in 20 mL CH2Cl2 at 0 °C. The
solution was allowed to stir for 1.5 h at 0 °C and then diluted with CH2Cl2 (30 mL) followed by
the addition of 2N NaOH (4 mL). The organic layer was separated and washed with 2N HCl (30
mL), brine (30 mL) and subsequently dried over anhydrous MgSO4. Filtration and removal of the
solvents in vacuum gave yellow oil which was purified by flash chromatography (ethyl
22
D
1
acetate/petroleum ether, 5:1; yield 1.85 g, 93%);
0.08 (s, 3H), 0.12 (s, 3H), 0.88 (s, 9H), 0.99 (t, 3H,
(q, 2H, = 7.0 Hz), 2.69 (dd, 1H, = 10.3 Hz), 3.05 (d, 2H,
13.2 Hz), 4.11–4.21 (m, 2H), 4.60–4.68 (m, 1H), 4.72 (t, 1H,
[α
]
= +15.8°; H NMR (400 MHz, CDCl3)
δ
J = 7.0 Hz), 1.14 (s, 3H), 1.17 (s, 3H), 2.55
J
J
J
= 5.2 Hz), 3.38 (dd, 1H,
J = 3.4 Hz,
J
= 5.2 Hz), 7.09–7.24 (m, 5H). 13C
ACS Paragon Plus Environment

Page 21 of 30
The Journal of Organic Chemistry
1
2
3
4
NMR (62.5 MHz, CDCl3)
δ
–4.9, –4.2, 7.7, 18.2, 19.4, 22.2, 26.0, 31.5, 38.0, 40.7, 52.7, 55.4,
5
6
7
8
66.2, 71.9, 127.3, 129.0, 129.4, 135.5, 153.5, 171.3, 215.7; IR (KBr) 3027 (w), 2956 (m), 2931
(m), 2885 (w), 2858 (w), 1784 (s), 1702 (s), 1598 (w), 1572 (m), 1455 (w), 1378 (s) 1351 (m),
1309 (m), 1253 (m), 1216 (m), 1088 (s), 1054 (w), 1024 (w), 1006 (w), 972 (w) cm–1;
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
C25H39NO5Si (461.67, 461.26), MS (ESIꢀMS):
m/z
(%) 461 (2) [M]+, 404 (98), 362 (18), 348 (9),
330 (13), 304 (100), 276 (10), 252 (25), 227 (20), 185 (17), 91 (9).
(3S)-3-(tert-butyl-dimethylsilanyloxy)-4,4-dimethyl-5-oxo-heptanoic
acid
(25).
30%
Hydrogen peroxide (1.11 mL, 9.66 mmol) and lithiumhydroxideꢀhydrate (0.14 g, 3.22 mmol)
were added to a cooled solution of compound 24 (0.74 g, 1.61 mmol) in THF/water (3:1, 36 mL)
at 0 °C. The reaction mixture was stirred for 1 h, followed by the addition of a solution of sodium
sulphite (1.4 g) in water (20 mL) and then buffered with NaHCO3. The volatile solvent was
removed in vacuum and the remaining aqueous phase was extracted with CH2Cl2 (3 × 5 mL). The
aqueous phase was acidified to pH 1 with 2N HCl and extracted again with CH2Cl2 (5 × 10 mL).
The combined organic layers were dried over anhydrous Na2SO4, filtered and concentrated in
vacuum. The remaining oil was purified by flash chromatography (ethyl acetate/petroleum ether,
22
D
1
1:2 + 1% acetic acid; yield 0.44 g, 90%):
[α
]
= −19.3°; H NMR (400 MHz, CDCl3)
δ
0.04 (s,
3H), 0.06 (s, 3H), 0.85 (s, 9H), 1.00 (t, 3H,
J
= 7.1 Hz), 1.09 (s, 3H), 1.15 (s, 3H), 2.29–2.55 (m,
13
4H), 4.47 (dd, 1H,
J = 3.6 Hz, 6.9 Hz). C NMR (62.5 MHz, CDCl3) δ –4.9, –4.3, 7.7, 18.2,
20.6, 21.1, 25.9, 31.8, 39.3, 52.6, 73.5, 178.0, 215.2; IR (KBr) 3300 (br), 2956 (s), 2932 (s), 2887
(w), 1736 (s), 1712 (s), 1472 (m), 1410 (m), 1389 (m) 1363 (w), 1303 (w), 1255 (m), 1216 (w),
1092 (s), 1026 (w), 1006 (w), 973 (w) cm–1; C15H30O4Si (302.48, 302.19), MS (CI, isobut.):
m/
z
(%) 303 (6) [M + H]+, 245 (95), 227 (58), 203 (25), 183 (18), 171 (43), 153 (60), 145 (79),
54
55
56
57
58
59
60
125 (46), 101 (100), 75 (94).
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 22 of 30
1
2
3
4
5
6
7
8
9
(3S)-6-Bromo-3-(tert-butyl-dimethylsilanyloxy)-4,4-dimethyl-5-oxo-heptanoic acid (9,
mixture of diastereomers). Phenyltrimethylammonium bromide (0.42 mL, 1.13 mmol) was
added to a cooled solution of compound 25 (0.33 g, 1.08 mmol) in THF at 0 °C. The reaction
mixture was stirred for 15 min at 0 °C and then allowed to come to room temperature followed
by an additional stirring for 1 h. Water (13 mL) was added to the reaction mixture and the organic
layer was separated while aqueous phase was extracted with Et2O (3 × 20 mL). The combined
organic layers were washed with 1N HCl (25 mL), brine (25 mL), dried over anhydrous Na2SO4,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
filtered and concentrated in vacuum. The remaining oil was purified by flash chromatography
22
D
(ethyl acetate/petroleum ether, 1:4 containing 2% acetic acid; yield 0.41 g, 98%):
1H NMR (400 MHz, CDCl3)
[α
]
= −40.8°;
δ
0.05 (s, 3H), 0.07 (s, 3H), 0.09 (s, 3H), 0.83 (s, 9H), 1.22 (s, 3H),
1.24 (s, 3H), 1.37 (s, 3H), 1.60–1.70 (m, 6H), 2.26 (dd, 1H,
J = 6.2 Hz, 16.9 Hz), 2.41 (dd, 1H, J
= 6.5 Hz, 16.8 Hz), 2.55 (dd, 1H,
(dd, 1H,
NMR (62.5 MHz, CDCl3)
J
= 3.6 Hz, 16.7 Hz), 2.69 (dd, 1H,
J = 4.1 Hz, 16.9 Hz), 4.25
J
= 4.2 Hz, 6.2 Hz), 4.49 (dd, 1H, J
= 3.6 Hz, 6.5 Hz), 4.75–4.88 (m, 2H); 13C
δ
–4.7, –4.6, –4.5, –4.3, 18.1, 20.4, 20.5, 21.1, 21.6, 21.9, 22.7, 25.6,
26.0, 39.5, 39.7, 41.5, 41.7, 52.7, 53.3, 73.3, 75.4, 177.2, 177.5, 208.3, 208.5; C15H29BrO4Si
(%) 383 (11) [M + H]+, 303 (25), 137 (27), 135 (27), 105
(381.38, 380.10), MS (CI, isobut.)
m/z
(20), 93 (30), 88 (100), 76 (49), 71 (46); HRMS (ESI)
381.1068.
m/z
[M + H]+ calcd 381.1907; found
(3S)-6-Bromo-3-(tert-butyldimethylsilyloxy)-4,4-dimethyl-5-oxo-heptanoic
acid-
(3Z,1S,8S)-9-(tert-butyldimethylsilyloxy)-4,8-dimethyl-1-[E-1-methyl-2-(2-methylthiazol-4-
yl)-vinyl]-non-3-enyl ester (26, mixture of diastereomers). EDCI (0.25 g, 1.29 mmol) was
added to a cooled solution of compound
8 (0.28 g, 0.64 mmol), (3S)ꢀ6ꢀbromoꢀ3ꢀ(tertꢀ
butyldimethylsilanyloxy)ꢀ4,4ꢀdimethylꢀ5ꢀoxoꢀheptanoic acid (9, 26 g, 0.64 mmol) and DMAP
ACS Paragon Plus Environment

Page 23 of 30
The Journal of Organic Chemistry
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
(8 mg, 0.064 mmol) in CH2Cl2 (3.50 mL) at 0 °C. The reaction mixture was stirred for 10 min at
0 °C and then 18 h at room temperature. The reaction mixture was extracted with diethyl ether
(50 mL). The combined organic extracts were washed with a half concentrated NaCl solution
(20 mL), brine (20 mL), dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The
remaining oil was purified by flash chromatography (ethyl acetate/petroleum ether, 1:4; yield
0.36 g, 70%): 1H NMR (250 MHz, CDCl3)
(m, 12H), 1.67 (s, 3H), 1.69 (dd, 3H, = 4.4 Hz), 1.92–2.05 (m, 2H), 2.08 (s, 3H), 2.22 (dd, 1H,
= 5.6 Hz), 2.33–2.54 (m, 2H), 2.66 (dd, 1H, = 4.8 Hz), 2.71 (s, 3H), 3.36 (dd, 1H, = 6.8 Hz,
δ 0.01–0.12 (m, 12H), 0.81–0.95 (m, 21H), 0.90–1.63
J
J
J
J
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
9.6 Hz), 3.45 (dd, 1H,
5.11 (m, 1H), 5.20 (dd, 1H,
CDCl3)
J
= 5.6 Hz, 9.6 Hz), 4.25 (dd, 1H), 4.56 (dd, 1H), 4.81–4.89 (m, 1H), 5.00–
J
= 3.2 Hz, 7.5 Hz), 6.50 (s, 1H), 6.96 (s, 1H); 13C NMR (62.5 MHz,
δ
−5.3, −4.8, −4.5, −4.2, −4.0, 14.9, 16.8, 18.1, 18.3, 19.2, 20.9, 21.3, 21.4, 21.5, 22.7,
22.9, 23.5, 26.0, 26.2, 31.6, 32.3, 33.2, 35.8, 39.8, 40.1, 41.7, 42.1, 52.6, 53.3, 68.3, 73.5, 75.6,
79.8, 116.3, 119.3, 121.0, 137.1, 138.6, 152.6, 164.5, 170.9, 208.3, 208.6; IR (KBr) 667 (w), 758
(s), 777 (s), 814 (w), 837 (s), 1005 (w), 1024 (w), 1094 (s), 1181 (m), 1215 (w), 1254 (m), 1294
(w), 1362 (w), 1375 (w), 1387 (w), 1447 (w), 1471 (m), 1507 (w), 1709 (m), 1734 (m), 2857 (s),
2928 (s) 2955 (s) cm–1; C39H70BrNO5SSi2 (801.12, 799.37), MS (CI):
m/
z
(%) 802 (0.9) [M +
H]+, 800 (0.6) [M + H]+, 420 (75), 168 (100). HRMS (ESI)
824.3568.
m/z
[M + Na]+ 824.3557; found
(3S)-6-Bromo-3-(tert-butyldimethylsilyloxy)-4,4-dimethyl-5-oxo-heptanoic acid (3Z,1S,
8S)-9-hydroxy-4,8-dimethyl-1-[E-methyl-2-(2-methyl-thiazol-4-yl)-vinyl]-non-3-enyl ester
(27, mixture of diastereomers). Compound 26 (0.32 g, 0.41 mmol) was dissolved in a (1:1)
mixture of CH2Cl2 and MeOH (12.4 mL) and cooled to 0 °C. CSA (97 mg, 0.42 mmol) was
added to this solution and allowed to stir for 2.5 h at 0 °C. The reaction mixture was treated with
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 24 of 30
1
2
3
4
5
6
triethylamine (64 mg, 87 ꢁL, 0.63 mmol) and concentrated under reduced pressure. The residue
oil was purified by flash chromatography (ethyl acetate/petroleum ether, 1:2; yield 0.24 g, 86%):
7
8
9
1H NMR (250 MHz, CDCl3)
0.99–1.67 (m, 4H), 1.07 (s, 3H), 1.17 (s, 3H), 1.37 (s, 3H), 1.57–1.63 (m, 3H), 1.60 (s, 3H),
1.72–1.88 (bs, 1H) 1.89–2.10 (m, 2H), 2.00 (s, 3H), 2.16 (dd, 1H, = 5.6 Hz), 2.53–2.49 (m,
2H), 2.60 (dd, 1H, = 4.8 Hz), 2.65 (s, 3H), 3.37 (dd, 1H, = 6.8 Hz), 3.43 (dd, 1H, = 6.0 Hz),
δ 0.00–0.03 (m, 6H), 0.72–0.89 (m, 9H), 0.85 (d, 3H, J = 6.8 Hz),
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
J
J
J
J
4.16–4.40 (m, 1H), 4.75–4.81 (m, 1H), 4.99–5.35 (m, 1H), 5.11–5.17 (m, 1H), 6.45 (s, 1H), 6.92
(s, 1H); 13C NMR (62.5 MHz, CDCl3)
δ
−5.1, −5.0, −4.6, −4.4, 14.5, 16.5, 19.0, 19.4, 20.2, 21.3,
21.5, 22.6, 22.9, 23.7, 25.8, 26.2, 31.5, 32.1, 33.9, 35.5, 39.7, 40.2, 41.5, 42.4, 52.4, 53.1, 67.8,
73.7, 75.5, 79.8, 116.2, 119.2, 121.0, 137.0, 138.3, 152.3, 164.5, 170.8, 208.2, 208.7; IR (KBr)
733 (s), 756 (w), 779 (m), 837 (s), 910 (w), 1003 (w), 1024 (w), 1061 (m), 1094 (m), 1182 (s),
1255 (m), 1294 (w), 1375 (m), 1386 (m), 1420 (w), 1437 (w), 1447 (w), 1456 (m), 1472 (m),
1507 (m), 1520 (w), 1541 (m), 1559 (m), 1653 (m), 1684 (w), 1701 (s), 1717 (s), 1734 (s), 2859
(m), 2934 (s), 2955 (s) cm–1. C33H56BrNO5SSi2 (686.86, 685.28), MS (CI)
m/
z
(%) 688 (1.6) [M
+ H]+, 686 (1.1) [M + H]+, 306 (100), 168 (100). HRMS (ESI)
found 710.2704.
m/z
[M + Na]+ calcd 710.2685;
(3S)-6-Bromo-3-(tert-butyl-dimethyl-silanyloxy)-4,4-dimethyl-5-oxo-heptanoic acid (1S
,3Z,8S)-9-hydroxy-4,8-dimethyl-1-[(1E)-methyl-2-(2-methyl-thiazol-4-yl)-vinyl]-9-oxo- non-
3-enyl ester (7, mixture of diastereomers). SO3•Pyridine complex (0.20 g, 1.22 mmol) was
added to a cooled solution of compound 27 (0.18 g, 0.26 mmol), DMSO (1.72 mL), triethylamine
(0.16 mg, 0.21 mL, 1.53 mmol) and CH2Cl2 (5.30 mL) at 0 °C. The resulting mixture was stirred
for 60 min at 0 °C and then extracted with diethyl ether (40 mL), washed with water (2 × 50 mL)
and brine (10 mL). The organic layer was dried over anhydrous Na2SO4, filtered and
ACS Paragon Plus Environment

Page 25 of 30
The Journal of Organic Chemistry
1
2
3
4
concentrated in vacuum to yield slightly yellow oil which was used in the following reaction step
5
6
without any further purification (yield 0.15 g, 84%): 1H NMR (250 MHz, CDCl3)
δ 0.09 (s, 6H),
7
8
9
0.75 (s, 12H), 0.98–1.17 (m, 6H), 1.36–1.51 (m, 4H), 1.65 (s, 3H), 1.94–2.11 (m, 3H), 2.14–2.65
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
(m, 10H), 2.63 (s, 3H), 4.18–4.45 (m, 1H), 4.72–4.86 (m, 1H), 5.01–5.12 (m, 1H), 5.14–5.21 (m,
13
1H), 6.41 (s, 1H), 6.88 (s, 1H), 9.53 (d, 1H,
J
= 1.6 Hz). C NMR (62.5 MHz, CDCl3)
δ
–4.5, –
4.4, –4.0, –3.8, 13.8, 15.1, 18.5, 19.6, 20.8, 21.0, 21.1, 22.1, 22.6, 23.8, 25.6, 26.4, 30.7, 31.5,
32.3, 40.2, 41.1, 41.6, 42.6, 46.7, 53.0, 53.7, 73.9, 76.0, 80.2, 116.8, 120.3, 121.6, 124.7, 137.4,
137.7, 138.2, 152.9, 153.0, 164.6, 170.3, 205.3, 208.8, 209.0; C33H54BrNO5SSi (684.84, 683.27),
MS (CI)
m
/
z
(%) 684 (4) [M + H]+, 606 (16) [M + H − Br]+, 474 (20), 372 (49), 355 (18), 306
[M + H]+ 684.2753; found 684.2753.
(18), 304 (17), 271 (100). HRMS (ESI) m/z
(13Z,4S,7R,8S,9S,16S)-4-(tert-Butyldimethylsilyloxy)-8-hydroxy-5,5,7,9,13-pentamethyl-
16-[E-1-methyl-2-(2-methylthiazol-4-yl)-vinyl]-oxacyclohexadec-13-ene-2,6-dione (28).
solution of compound (80 mg, 0.12 mmol) in THF (5.0 mL) was added to a suspension of
A
7
CrCl2 (35 mg, 0.28 mmol) and LiI (30 mg, 0.22 mmol) in dry THF (25 mL) over a period of
80 min via syringe pump. The resulting suspension was stirred a further 2 h at ambient
temperature and then quenched with half concentrated NH4Cl (20 mL). The organic phase was
extracted with ether (5 × 15 mL), washed with demineralised water (2 × 15 mL), brine (15 mL),
dried over anhydrous Na2SO4, filtered and concentrated in vacuum. The residue oil was purified
1
by flash chromatography (ethyl acetate/petroleum ether, 5:1; yield 16.2 mg, 22%): H
NMR (250 MHz, CDCl3)
3H, = 7.2 Hz), 1.14–1.17 (m, 9H), 1.66 (s, 3H), 1.98–2.89 (m, 4H), 2.10 (s, 3H), 2.71 (s, 3H),
2.95–3.04 (bs, 1H), 3.03–3.07 (m, 1H), 3.80–3.89 (m, 1H), 4.06 (dd, 1H, = 4.0 Hz, 8.8 Hz),
δ 0.07 (s, 3H), 0.12 (s, 3H), 0.83 (s, 9H), 0.86–1.86 (m, 7H), 1.03 (d,
J
51
52
53
54
55
56
57
58
59
60
J
4.98 (dd, 1H,
J
= 10.0 Hz), 5.13–5.17 (m, 1H), 6.48 (s, 1H), 6.94 (s, 1H). 13C
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 26 of 30
1
2
3
4
NMR (62.5 MHz, CDCl3)
δ
–4.3, –3.6, 13.0, 15.3, 15.8, 18.2, 19.3, 22.3, 22.9, 23.0, 25.9, 31.9,
5
6
7
8
32.5, 37.9, 34.2, 40.1, 41.4, 53.7, 72.8, 73.3, 79.6, 116.2, 120.1, 120.8, 137.7, 138.3, 152.6,
164.7, 170.3, 220.1; IR (KBr) 731 (m), 777 (s), 835 (s), 937 (w), 974 (w), 986 (w), 1063 (w),
1094 (m), 1134 (w), 1163 (m), 1179 (m), 1204 (w), 1252 (w), 1412 (m), 1451 (m), 1468 (s),
1501 (m), 1512 (m), 1530 (w), 1547 (m), 1564 (w), 1582 (w), 1688 (s), 1740 (s), 2857 (m), 2930
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(s), 2959 (m) cm−1. C33H55NO5SSi (605.94, 605.36), HRMS (ESI)
found 628.3462.
m/z
[M + Na]+ 628.3452;
(13Z,4S,7R,8S,9S,16S)-4,8-Dihydroxy-5,5,7,9,13-pentamethyl-16-[E-1-methyl-2-(2-
methylthiazol-4-yl)-vinyl]-oxacyclohexadec-13-ene-2,6-dione (epothilone D, 4). TFA (200
ꢁL) was added to a cooled solution of 28 (7 mg, 0.012 mmol) in methylene chloride (1 mL) at 0
°C. The solution was stirred at 0 °C over a period of 90 min and then extracted with methylene
chloride (20 mL). The organic extract was washed with saturated NaHCO3 solution (2 × 10 mL),
water (10 mL), brine (10 mL), dried over anhydrous Na2SO4, filtered and concentrated in
vacuum. The residue yellow oil was purified by flash chromatography (ethyl acetate/petroleum
ether, 1:2; yield 4.1 mg, 69%): 1H NMR (400 MHz, CD3OD)
Hz), 1.20 (d, 3H, = 7.0 Hz), 1.25–1.56 (m, 5H), 1.32 (s, 3H), 1.69 (s, 3H), 1.69–1.78 (m, 1H),
1.84–1.91 (m, 1H), 2.05 (s, 3H), 2.22 (dd, 1H, = 6.0 Hz, 15.0 Hz), 2.35–2.16 (m, 2H), 2.69 (s,
3H), 2.68–2.75 (m, 1H), 3.23 (dq, 1H, = 7.0 Hz), 3.30–3.31 (m, 2H), 3.65 (dd, 1H,
6.7 Hz), 4.30 (dd, 1H,
NMR (125 MHz, CD3OD)
δ 1.00 (s, 3H), 1.01 (d, 3H, J = 7.5
J
J
J
J
= 3.0 Hz,
13
J
= 4.0 Hz, 10.0 Hz), 5.18–5.23 (m, 2H), 6.57 (s, 1H), 7.22 (s, 1H). C
δ
15.7, 16.2, 17.5, 18.6, 18.9, 19.3, 19.5, 23.4, 23.4, 32.8, 38.5, 39.9,
40.8, 45.5, 49.3, 72.5, 77.5, 80.7, 117.4, 120.0, 121.6, 140.2, 140.3, 166.0, 167.0, 220.3;
[M + Na]+ 614.2594; found 614.2598.
C27H41NO5S (491.68, 491.27), HRMS (ESI) m/z
ACS Paragon Plus Environment

Page 27 of 30
The Journal of Organic Chemistry
1
2
3
4
Acknowledgments
5
6
7
8
We thank Dr. Andrea Porzel for NMRꢀsupport, Dr. Sander van Berkel for manuscript help,
Florenz Sasse (GBF/HZI) and Annika Denkert for bioassays, and Prof. Höfle (GBF/HZI) for
reference compounds and spectra. Part of this work was financed by the HWP program through
the state of SaxonyꢀAnhalt. Very special thanks go to the late Gisela Schmidt for her valuable
technical assistance.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Supporting Information
1
General experimental procedures and copies of H and 13C NMR spectra. This material is
available free of charge via the Internet at http://pubs.acs.org.
References and Footnotes
(1) (a) Gerth, K.; Bedorf, N.; Höfle, G.; Irschitk, H.; Reichenbach, H. J. Antibiot. 1996
560. (b) Höfle, G.; Bedorf, N.; Steinmetz, H.; Schomburg, D.; Gerth, K.; Reichenbach, H.
Angew. Chem. 1996 108, 1671; Angew. Chem. Int. Ed. 1996 35, 1567.
(2) (a) Feyen, F.; Cachoux, F.; Gertsch, J.; Wartmann, M.; Altmann, K.ꢀH. Acc. Chem. Res.
2008 41, 21. (b) Altmann, K.ꢀH.; Cachoux, F.; Caravatti, G.; Isarno, T.; Wartmann, M.
ARKIVOC 2006 , 131.
(3) (a) Kingston, D. G. I. J. Nat. Prod. 2009
Wartmann, K.ꢀH. Altmann, Org. Lett. 2008 10, 1183.
(4) (a) Mulzer, J.; Altmann, K.ꢀH.; Höfle G.; Müller, R.; Pratz, K. C. R. Chimie 2008
, 49,
,
,
,
,
8
,
72, 507. (b) Kuzniewski, C. N.; J. Gertsch, M.
,
,
,
11, 1336.
(b) Hurski, A. L.; Kulinkovich, O. G. Russ J Org Chem 2011, 47, 1653. (c) Harrison, M.;
ACS Paragon Plus Environment

The Journal of Organic Chemistry
Page 28 of 30
1
2
3
4
Swanton, C. Expert Opin. Invest. Drugs 2008
,
17, 523. (d) Wessjohann, L. A.; Angew. Chem.
5
6
1997
,
109, 738; Angew. Chem. Int. Ed. 1997, 36, 715. (e) Scheid, G.; Ruijter, E.; Konarzyckaꢀ
7
8
9
Bessler, M.; Bornscheuer, U. T.; Wessjohann, L. A. TetrahedronꢀAsymmetry 2004, 2861. (f)
Wessjohann, L. A.; Scheid, G. in Organic Synthesis Highlights Ed.: WileyꢀVCH, Weinheim
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
2000, 251. (g) Gabriel, T.; Wessjohann L. A. Tetrahedron Lett. 1997
corrigendum of the stereochemical assignment). (h) Gabriel, T.; Wessjohann L. A. Tetrahedron
Lett. 1997 38, 4387. (i) Hurski, A. L.; Kulinkovich, O. G. Tetrahedron Lett. 2010, 51, 3497. (j)
Martin, N.; Thomas, E. J. Org. Biomol. Chem. 2012 10, 7952. (k) Balog, A.; Harris, C.; Savin,
K.; Zhang, X. G.; Chou, T. C.; Danishefsky, S. J. Angew. Chem. Int. Ed. 1998 37, 2675. (l)
Nicolaou, K. C.; Ninkovic, S.; Sarabia, F.; Vourloumis, D.; He, Y.; Vallberg, H.; Finlay, M. R.
V.; Yang, Z. J. Am. Chem. Soc. 1997 119, 7974. (m) May, S. A.; Grieco, P. A. Chem. Commun.
1998, 1597. (n) Mulzer, J.; Mantoulidis, A.; Öhler, E. Tetrahedron Lett. 1998 39, 8633. (o)
Altmann, K.ꢀH.; Gertsch, J. Nat. Prod. Rep 2007 24, 327.
(5) (a) Doi, T.; Fuse, S.; Miyamoto, H.; Nakai, K.; Sasuga, D.; Takahashi, T.; Chem.ꢀAsian J.
2006 , 370. (b) Baloglu, E.; Kingston, D. G. I. J. Nat. Prod 1999 62, 1068. (c) Nicolaou, K.
C.; Dai, W.ꢀM.; Guy, R. K. Angew. Chem 1994 106, 38; Angew. Chem. Int. Ed. 1994 33, 15.
, 38, 1363 (see ref. 4h for a
,
,
,
,
,
.
,
,
1
.
,
.
,
,
(d) Luo, C.; Wang, Y.; Chen, Q.; Han, X.; Liu, X.; Sun, J.; He, Z. MiniꢀRev. Med. Chem. 2012
12, 434.
,
(6) Tang, L.; Shah, S.; Chung, L.; Carney, J.; Katz, L.; Khosla, C.; Julien, B. Science 2000
287, 640.
,
(7) (a) Ter Haar, E.; Kowalski, R. J.; Hamel, E.; Lin, C. M.; Longley, R. E.; Gunasekera, S. P.;
Rosenkranz, H. S.; Day, B. W. Biochemistry 1996 35, 243. (b) Hamel, E.; Sackett, D. L.;
Vourloumis, D.; Nicolaou, K. C. Biochemistry 1999 38, 5490.
,
,
ACS Paragon Plus Environment

Page 29 of 30
The Journal of Organic Chemistry
1
2
3
4
(8) (a) Snyder, J. P.; Nettles, J. H.; Cornett, B.; Downing, K. H.; Nogales, E. Proc. Natl. Acad.
5
6
7
8
Sci. U.S.A. 2001
(c) Nettles, J. H.; Li, H.; Cornett, B.; Krahn, J. M.; Snyder, J. P.; Downing, K. H. Science 2004
305, 866. (d) Carlomagno, T.; Blommers, M. J. J.; Meiler, J.; Jahnke, W.; Schupp, T.; Petersen,
F.; Schinzer, D.; Altmann, K. H.; Griesinger, C. Angew. Chem. Int. Ed. 2003 42, 2511. (e) Prota,
A. E.; Bargsten, K.; Zurwerra, D.; Field, J. J.; Díaz, J. F.; Altmann, K. H.; Steinmetz, M. O.
Science 2013 339, 587.
(9) Ferrandina, G.; Mariani, M.; Andreoli, M.; Shahabi, S.; Scambia, G.; Ferlini, C. Curr.
Pharm. Design 2012 18, 2793.
(10) (a) Krause, W.; Klar, U. Curr. Cancer Ther. Rev. 2011
D. ; Lyman, G. H. Curr. Breast Cancer Rep. 2013 , 51. (c) DiazꢀPadilla, I.; Oza, A. M. Future
Oncol. 2011 , 559.
(11) (a) Kuzniewski, C. N.; Gertsch, J.; Wartmann, M.; Altmann, K.ꢀH. Org. Lett.
, 98, 5312. (b) Nogales, E.; Wolf, S. G.; Downing, K. H. Nature 1998, 391, 199.
,
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
,
,
,
, 7, 10. (b) Hirsch, B. R.; Reed, S.
,
5
,
7
,
2008, 10,
1183. (b) Nicolaou, K. C.; Ritzen, A.; Namoto, K. Chem. Commun. 2001, 1523. (c) Bold, G.;
Wojeik, S.; Caravatti, G.; Lindauer, R.; Stierlin, C.; Gertsch, J.; Wartmann, M.; Altmann, K.ꢀH.
ChemMedChem 2006
ChemBioChem 2006
Agents 2002
1277. (g) Altmann, K.ꢀH. Curr. Opin. Chem. Biol. 2001
Giannakakou, P.; Hamel, E. J. Biol. Chem. 1997 272, 2534. (i) Wolff, A.; Technau, A.;
Brandner, G. Int. J. Oncol. 1997 11, 123. (j) Nicolaou, K. C.; Vourloumis, D.; Li, T.; Pastor, J.;
Winssinger, N.; He, Y.; Ninkovic, S.; Sarabia, F.; Vallberg, H.; Roschangar, F.; King, N. P.;
,
1
, 37. (d) Cachoux, F.; Isarno, T.; Wartmann, M.; Altmann, K.ꢀH.
,
7
, 54. (e) Wartmann, M.; Altmann, K.ꢀH. Curr. Med. Chem. AntiꢀCancer
,
2
, 123. (f) Stachel, S. J.; Biswas, K.; Danishefsky, S. J. Curr. Pharm. Des. 2001
, 7,
,
5
, 424. (h) Kowalski, R. J.;
,
,
Finlay, M. R. V.; Giannakakou, P.; VerdierꢀPinard, P.; Hamel, E. Angew. Chem. 1997, 109,
ACS Paragon Plus Environment