Single and double ring closing metathesis in the formation of dihydropyrans and bisoxacyclic systems with a quaternary centre

Article abstract of DOI:10.1039/b004302h

Starting from α-hydroxy carboxylic acid esters, allyl homoallyl ethers with a quaternary centre become available in a one-pot reaction via a sequence of O-allylation-Wittig-rearrangement-O-allylation. Elaboration of the side chain provides various precurs

Full text of DOI:10.1039/b004302h

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Single and double ring closing metathesis in the formation of
dihydropyrans and bisoxacyclic systems with a quaternary centre
Bernd Schmidt* and Holger Wildemann
1
Universität Dortmund, Fachbereich Chemie, Organische Chemie, Otto-Hahn-Straße 6,
D-44227 Dortmund, Germany. Fax: ϩ49 (231)7555363;
E-mail: bschmidt@citrin.chemie.uni-dortmund.de
Received (in Cambridge, UK) 31st May 2000, Accepted 6th July 2000
Published on the Web 3rd August 2000
Starting from α-hydroxy carboxylic acid esters, allyl homoallyl ethers with a quaternary centre become available in
a one-pot reaction via a sequence of O-allylation–Wittig-rearrangement–O-allylation. Elaboration of the side chain
provides various precursors for dihydropyrans and bisoxacyclic systems, which become available by single or double
ring closing metathesis. Double ring closing metathesis of the substrates investigated in this study is highly
regioselective to give dihydropyrans linked via a C–C-bond to a dihydrofuran or an oxepine. The regioisomeric fused
products are not formed in the reaction.
Introduction
The discovery of ruthenium carbene complexes as efficient
catalysts for ring closing metathesis by Grubbs and co-
workers1–3 has led to a manifold of different applications of
this synthetic method. Thus, over the past few years ring
closing metathesis has turned out to be an efficient tool for
the preparation of medium-sized and large carba- and
heterocycles.4–6 In the field of heterocyclic chemistry the
majority of contributions deal with the synthesis of oxa- and
azacycles, and many efforts have been made to develop syn-
thetic methodologies for suitably functionalized precursors.
With a view towards C-glycosides7–9 and other functionalized
tetrahydropyrans10,11 we became interested in the synthesis
Scheme 1
of functionalized α,ω-unsaturated ethers as precursors for
dihydropyrans with a quaternary centre in the 2-position.12,13
While several dihydropyrans are accessible by allylation of a
homoallylic alcohol and subsequent ring closing metathesis
(RCM),2,14–17 many substitution patterns require syntheses
which are not straightforward. Some of the established solu-
tions over the past few years include Claisen rearrangement–
RCM sequences,18,19 asymmetric aldol addition–RCM strate-
gies,20,21 and the introduction of olefinic moieties onto carbo-
hydrate scaffolds.22–27 Elaboration of α-bromo acids or esters
into RCM precursors for dihydropyrans has been investigated
by us,12,28 and related strategies have been used for the construc-
tion of seven- and eight-membered oxacycles by others.29,30 In
the course of our studies towards hydroxylated dihydro-
pyrans,31 esters of α-hydroxy carboxylic acids32 were found to
be useful starting materials: O-allylation and elaboration of the
ester moiety into an allylic alcohol provides appropriately sub-
stituted metathesis precursors in two steps. In this contribution,
we present an olefin metathesis based synthesis of dihydro-
pyrans with an ester functionality in the side chain using the
same starting materials (Scheme 1).
Scheme 2 Reagents and conditions i) NaH (excess), allyl bromide,
THF, 65 ЊC, (36–44%).
commercially available and inexpensive starting materials
1a–c with NaH and allyl bromide (Scheme 2). Though yields
are moderate, this reaction can be performed on a compara-
tively large scale and does not require any protecting group
chemistry.
The effect of different functional groups in the side chain on
the efficiency of the olefin metathesis reaction was studied. The
metathesis precursors investigated here can be elaborated in two
steps into tetraenes, which may undergo a double ring closing
metathesis reaction leading to bisoxacyclic systems.
Formation of 2a–c may be regarded as a sequential reac-
tion. The first step of the sequence is an O-allylation to give
3, followed by a Wittig-rearrangement (yielding a tertiary
alcohol 4) which is finally allylated to the corresponding
allyl homoallyl ethers 2a–c. α-Allylation of hydroxy esters or
protected derivatives has also been used for the preparation
of tertiary alcohols of type 4.33–35 Elucidation of this mech-
anism was achieved by isolation of the intermediates. Reaction
of (S)-ethyl lactate with a slight excess of NaH and allyl
bromide at elevated temperature yields the O-allylated racemic
Results and discussion
Synthesis of appropriately functionalized metathesis precursors
2a–c was achieved in a one-pot reaction by treatment of the
2916
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
This journal is © The Royal Society of Chemistry 2000
DOI: 10.1039/b004302h

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product 3 exclusively.31 Reaction of methyl mandelate under
the same conditions gives a 1:2 mixture of 3 and its Wittig-
rearrangement product 4, along with unreacted starting
material. Due to the mechanism, racemisation occurs during
this sequence if enantiomerically pure α-hydroxy esters are
employed. This has been proven by measurement of the optical
rotation ([αD] = 0) of intermediate 3b and by NMR-shift
experiments (Scheme 3).
With the metathesis precursors 2,5,6,8,10,11 in hand,
efficiency of the ring closing metathesis reaction was examined.
Scheme 5 and Table 1 summarize the results. Using Grubbs’
Scheme 3
Synthetic modification of the ester functionality in 2a,b,c
provides convenient access to other functionalized metathesis
precursors (Scheme 4): addition of excess vinylmagnesium
chloride gave the product of two consecutive additions: thus,
the α,β-unsaturated ketone initially formed reacted further
through a 1,4-addition to yield exclusively the 1,4-addition
compounds 5a,b. Reduction of esters 2a,b,c or ketones 5a,b
with DIBAL-H furnishes secondary alcohols 6a,b and primary
alcohols 10a,b,c, respectively. Reduction of the carbonyl
functionality in ketone 5a proceeds with high diastereo-
selectivity to give 6a, whereas 6b is obtained as a 1:1 mix-
ture under these conditions. The stereochemical result for
the formation of 6a can be explained if chelation control
(“Cram’s cyclic model”) is assumed.36 Secondary alcohols 8a,b
are prepared by reduction of the ester groups in 2a,b to the
corresponding aldehydes and addition of vinylmagnesium
chloride in a one-pot reaction. The reaction is moderately
diastereoselective (2.4:1 for 8a, 2:1 for 8b) and the diastereo-
mer shown in Scheme 4 is formed in preference, and is the
isomer expected on the basis of the Felkin-Anh model.37 In the
case of 6a as well as in the case of 8a,b, the relative stereo-
chemistry was tentatively assigned on the basis of the
NMR-data. A metathesis precursor with an aldehyde function-
ality in the side chain is obtained by oxidation of 10a to the
corresponding aldehyde 11a using PDC. Substrates 7a,b, 9a,b
and 12c suited for the study of double ring closing metathesis
reactions become accessible by allylation of alcohols 6a,b, 8a,b
and 10c. The syntheses are summarized in Scheme 4.
Scheme 5 Reagents and conditions i) A, DCM, 20 ЊC; ii) B, toluene,
110 ЊC (see Table 1).
Scheme 4 Reagents and conditions i) H2C᎐CHMgCl (excess), ether, Ϫ70 ЊC, (64–78%); ii) DIBAL-H, ether, Ϫ78 ЊC, (64–99%); iii) DIBAL-H,
᎐
H2C᎐CHMgCl, ether, Ϫ90→20 ЊC (50–78%); iv) PDC, DCM, 20 ЊC, (67%); v) NaH, THF, 65 ЊC, allyl bromide (58–96%).
᎐
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
2917

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Table 1 Ring closing metathesis reactions, conditions and yields (see Scheme 4)
Catalyst
Catalyst
Starting
material
loading (%)a
(Yield) (%)
loading (%)b
(Yield) (%)
Entry
Rٞ
Product
1
2
3
4
5
6
7
8
9
10
11
12
13
COOMe
COOEt
COOBu
–C(O)(CH2)2CH᎐CH2
–C(O)(CH2)2CH᎐CH2
–CH(OH)(CH2)2CH᎐CH2
–CH(OH)(CH2)2CH᎐CH2
–CH2OH
–CH2OH
–CH2OH
–CHO
2a
2b
13a
3 (90)
3 (95)
3 (72)
10 (74)
3 (0)
3 (65)
3 (42)
3 (86)
3 93)
3 (66)
8 (69)d
3 (40)
3 (17)
3 (98)
4 (87)
4 (96)
—
13b
2c
13c
5a
14a
᎐
᎐
5b
14b
6 (—c)
—
6a
15a ؉ 20 (3:1)
᎐
᎐
6b
15b
16a
16b
16c
17a
18a
19b
—
—
—
—
—
—
—
10a
10b
10c
11a
8a
–CH(OH)CH᎐CH2
–CH(OH)CH᎐CH2
᎐
᎐
8b
a Conditions: A, DCM, 20 ЊC. b Conditions: B, toluene, 100 ЊC. c Conditions: reaction stopped at 50% conversion. d Conditions: A, toluene, 100 ЊC.
catalyst (A), ring closing metathesis is a smooth process for
most starting materials. Normally, the reaction is quantitative
with a catalyst loading of 3 mol% after 3 hours at ambient
temperature. Ketones 5a,b and aldehyde 11a do not react under
these conditions. These results are in accord with observations
recently published by Fürstner et al. in the course of their
studies directed to the synthesis of macrocyclic lactones: in
certain cases, the presence of a carbonyl oxygen may inhibit the
ring closing metathesis reaction by formation of a stable chelate
complex.38 The authors were able to circumvent this problem by
addition of TiOi-Pr4 as a Lewis-acid, in our case, however, no
effect is observed. Ketone 5a finally undergoes ring closing
metathesis when the catalyst loading is increased to 10% and
the reaction time to 24 hours. In the case of aldehyde 11a,
rapid conversion to dihydropyran 17a is achieved with a cata-
lyst loading of 8 mol% in refluxing toluene, whereas virtually
no catalysis is observed under the standard conditions. The
isolated yield, however, is moderate due to the formation of a
variety of unidentified side products. We have also investigated
the use of the novel carbene complex B for ring closing meta-
thesis.39 Its preparation is very convenient and avoids the use
of hazardous starting materials.40 Very recently, the correct
carbene complex structure, rather than an allenylidene type
structure41 was published for B.42,43 Very rapid conversion
is observed for ring closing metathesis of 2a–c with complex
B in refluxing toluene, whereas virtually no conversion is
observed at ambient temperature. Isolated yields are com-
parable to those obtained with Grubbs’ catalyst, and in the
case of 13c significantly better. Ring closing metathesis of
ketone 5b in the presence of 4 mol% of B proceeds rapidly in
refluxing toluene, however, the reaction stops at approximately
50% conversion. Thus, regardless of the catalyst employed, it
appears to be more efficient for preparative purposes to conduct
the RCM step with ester or alcohol functionalities in the side
chain and modify these subsequently, if required. Ring closing
metathesis of trienes 5, 6 and 8 may in principle yield three
different isomers. In the case of ketones 5, only one isomer was
detected as outlined above. In contrast, ring closing metathesis
of 6a yields an inseparable 3:1 mixture of dihydropyran 15a
and cycloheptene 20 (Table 1, entry 6). Under the same condi-
tions, the methyl analogue is converted to the dihydropyran
15b. From ring closing metathesis of triene 8a (employed as
a single diastereomer) the dihydropyran 18a results as the
only isolable product in moderate yield, whereas the analo-
gous methyl compound 18b (employed as a 2:1 mixture of
diastereomers) is converted in poor yield (17%) to the
dihydropyrans 19b (2:1 mixture of diastereomers). It is quite
striking that in nearly all cases where more than two olefinic
moieties are available for ring closing metathesis, the yields are
moderate (Table 1, entries 4–7) or poor (Table 1, entries 12, 13).
We assume that a considerable amount of material is lost by
intermolecular metathesis leading to oligomers in these cases,
because the mass of crude material obtained from the ring
closing metathesis reactions corresponds quite well to the
expected amount, thus, it is unlikely that a significant amount
of material is lost due to decomposition in volatile low-
molecular weight fragments. There is obviously a strong
preference for the formation of dihydropyrans over cyclo-
alkenes or larger oxacycles. If two different six membered rings
can result from the metathesis reaction (entries 12, 13, form-
ation of 18a and 19b) the steric demand of the substituents
seems to exert some influence on the regiochemical outcome
of the cyclization.
Tetraenes can undergo a double ring closing metathesis lead-
ing to bicyclic products. For the tetraenes 7a,b and 9a,b in
principle three different regioisomers may result: two annelated
bicyclic products, and a product where two oxacycles are linked
by a carbon–carbon single bond. Products of this type are the
only ones observed for double ring closing metathesis of 7a,b
and 9a,b. No carbacycles can be isolated from the reaction mix-
ture, which is in accord with observations recently published by
Mioskowski and co-workers for the formation of bisoxacyclic
systems linked by methylene or ethylene bridges.44 It is likely
that cycloalkenes are formed as intermediates, however, a ring
opening–ring closing metathesis sequence45–50 may convert
these to the final bisoxacyclic products 21 and 22. Double ring
closing metathesis of tetraene 12c is also highly regioselective,
leading to a spirocyclic product 23c (Scheme 6). A cylcopentene
can be assumed as an intermediate, however, it could not be
detected from the reaction mixture.51
Structural assignment is based on H,H-COSY experiments
and on the analysis of geminal and vicinal coupling constants.
In the case of tetraenes 9a,b, the alternative cyclization mode
(formation of a fused dihydropyran-oxepine system 24) can
3
be excluded, because the coupling constant J(H2Ј-H3Ј) of 6
Hz and the 13C NMR data for the ether carbon atoms of the
dihydrofuran fragment are indicative for the structure depicted
in Scheme 6. NMR data for fused seven membered–six mem-
bered ring systems 24 are significantly different.52 The relative
stereochemistry was determined by NOESY experiments.
Conclusions
In conclusion we have developed a ring closing metathesis
based synthesis of dihydropyrans and bisoxacyclic systems with
a quaternary centre in the 2-position starting from α-
hydroxy esters. Suitable metathesis precursors are available
fromtheseinexpensivestartingmaterialsinaone-pot-reactionby
a sequential O-allylation–Wittig-rearrangement–O-allylation
reaction. Efficiency of the ring closing metathesis reaction
2918
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925

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cedure.3 Ruthenium complex B was prepared following a
procedure by Hill and co-workers.40
General procedure for the preparation of allyl homoallyl ethers 2
from ꢀ-hydroxy esters
NaH (40.0 g, 60% dispersion in mineral oil, 1.00 mol) was
slowly added to a solution of the corresponding α-hydroxy
ester (0.87 mol) in THF (300 mL). After the addition was com-
pleted, the mixture was heated to reflux for 1 h, cooled to room
temperature and allyl bromide (93 mL, 1.08 mol) was added
dropwise. The reaction mixture was again heated to reflux for
1 h. Two further portions of NaH (40.0 g, 60% dispersion in
mineral oil, 1.00 mol) and allyl bromide (93 mL, 1.08 mol)
were added to the refluxing solution, and after each addition
heating was continued for 1 h. The reaction mixture was cooled
to room temperature, poured onto water (200 mL) and
extracted with MTBE. The combined organic layers were dried
with MgSO4, filtered and evaporated. The residue was purified
by distillation.
rac-2-Allyloxy-2-phenylpent-4-enoic acid methyl ester (2a).
Obtained from -methyl mandelate (34.7 g, 0.87 mol) as a
colourless liquid (26.0 g, 44%), bp 86 ЊC (0.07 mbar). Found: C,
73.1%; H, 7.4%. C15H18O3 requires C, 73.1%; H, 7.4%. IR
(film): ν/cmϪ1 732 m, 921 m, 1034 m, 1056 s, 1075 m, 1137 m,
1
1244 m, 1448 m, 1733 s; H NMR (400 MHz, CDCl3) δ 7.42–
7.37 (2H, Ph), 7.30–7.17 (3H, Ph), 5.87 (dddd, 1H, J = 17.3,
10.5, 5.3, 5.3, HC–CH2–O), 5.61 (dddd, 1H, J = 17.1, 10.3, 7.5,
6.3, HC–CH2–C), 5.25 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5,
H C᎐CH), 5.08 (dddd, 1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
5.01 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH), 4.97 (dm, 1H,
᎐
2
J = 10.3, H C᎐CH), 3.92 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5,
᎐
2
H2C–O), 3.76 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5, H2C–O), 3.63
(s, 3H, H3C–), 2.98 (dddd, 1H, J = 14.8, 7.5, 1.5, 1.5, H2C–C),
2.89 (dddd, 1H, J = 14.8, 6.3, 1.5, 1.5, H2C–C). 13C NMR (100
MHz, CDCl3) δ 172.7 (0), 139.2 (0), 134.4 (1), 132.1 (1), 128.2
(1), 127.9 (1), 126.1 (1), 118.5 (2), 116.4 (2), 84.0 (0), 65.5 (2),
52.3 (3), 40.1 (2). MS (EI) m/z (%) 205 (Mϩ Ϫ 41, 16), 189 (90),
157 (32), 145 (35), 129 (25), 105 (100), 71 (20).
Scheme 6 Reagents and conditions i) A (6 mol%), DCM, 20 ЊC, (41–
64%).
depends on the substitution pattern of the starting material.
While ester- or hydroxy-groups in the side chain give rapid
conversions and excellent yields with low catalyst loadings,
ketones and aldehydes do not react under the standard con-
ditions, presumably due to chelation of the catalytically active
species. If more than two terminal olefinic moities are available
for the metathesis reaction, yields drop in most cases due to
oligomerization reactions. Nevertheless, formation of six-
membered oxacycles seems to be strongly preferred over all
other regiochemical options. This becomes even more obvious
for double ring closing metathesis reactions, which proceed
with high regioselectivity to give exclusively dihydropyrans
which are linked to a five- or a seven-membered oxacycle via
a carbon–carbon bond.
rac-2-Allyloxy-2-methylpent-4-enoic acid ethyl ester (2b).
Obtained from (S)-ethyl lactate (60.0 g, 0.51 mol) as a colour-
less liquid (35.5 g, 44%), bp 85 ЊC (40 mbar). Found: C, 66.5%;
H, 9.1%. C11H18O3 requires C, 66.6%; H, 9.2%. IR (film) ν/cmϪ1
920 m, 1110 m, 1157 m, 1252 m, 1733 s, 2983 m. 1H NMR (400
MHz, CDCl3) δ 5.95 (dddd, 1H, J = 17.1, 10.5, 5.3, 5.3, HC–
CH2–O), 5.81 (dddd, 1H, J = 17.1, 10.0, 7.3, 7.3, HC–CH2–C),
5.31 (dm, 1H, J = 17.1, H C᎐CH), 5.15 (dm, 1H, J = 17.1,
᎐
2
H C᎐CH), 5.14–5.08 (2H, H C᎐CH), 4.20 (q, 2H, J = 7.3, H C–
᎐
᎐
2
2
2
O–C᎐O), 3.98 (d, 2H, J = 5.3, H C–O–C), 2.57 (dd, 1H,
᎐
2
J = 14.8, 7.3, H2C–C), 2.51 (dd, 1H, J = 14.8, 7.3, H2C–C), 1.42
(s, 3H, H3C–C), 1.30 (t, 3H, J = 7.3, H3C–CH2). 13C NMR (100
MHz, CDCl3) δ 173.6 (0), 137.4 (1), 132.4 (1), 118.3 (2), 116.3
(2), 79.8 (0), 65.7 (2), 60.7 (2), 42.7 (2), 21.1 (3), 14.1 (3). MS (EI)
m/z (%) 199 (Mϩϩ1, 100), 141 (50), 125 (30), 95 (18), 85 (20).
Experimental
General remarks
All experiments were conducted in dry reaction vessels in an
atmosphere of dry argon. Solvents were purified by standard
1
procedures. H NMR spectra were recorded at 400 MHz in
2-Allyl-2-allyloxypent-4-enoic acid butyl ester (2c). Obtained
from butyl glycolate (29.4 g, 0.22 mol) as a colourless liquid
(20.0 g, 36%), bp 80 ЊC (0.07 mbar). Deviating from the general
procedure, addition of NaH and allyl bromide was repeated
three times in this case. Found: C, 71.7%; H, 9.4%. C15H24O3
requires C, 71.4%; H, 9.6%. IR (film) ν/cmϪ1 918 s, 995 m, 1067
m, 1211 s, 1732 s, 2935 m, 2961 m. 1H NMR (400 MHz, CDCl3)
CDCl3 with CHCl3 as internal standard (δ = 7.24). 13C NMR
spectra were recorded at 100 MHz in CDCl3 with CDCl3 as
internal standard (δ = 77.0). J values are given in Hz. The num-
ber of coupled protons was analysed by DEPT experiments and
is denoted by a number in parentheses following the δC value.
Signal assignment for cyclic products follows a numbering
scheme where the oxygen atom is numbered 1 and the quater-
nary carbon C2. IR spectra were recorded as films on NaCl
plates or as KBr disks. The peak intensities are defined as
strong (s), medium (m), and weak (w). Mass spectra were
obtained at 70 eV. Melting points are not corrected. The
ruthenium catalyst A was prepared following Grubbs’ pro-
δ 5.88 (dddd, 1H, J = 17.3, 10.5, 5.5, 5.3, HC᎐CH ), 5.74 (dddd,
᎐
2
1H, J = 17.3, 10.3, 7.5, 7.5, HC᎐CH ), 5.70 (dddd, 1H, J = 17.3,
᎐
2
10.3, 7.5, 7.3, HC᎐CH ), 5.25 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5,
᎐
2
H C᎐CH), 5.10 (dddd, 1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
5.09–5.03 (4H, H C᎐CH), 4.08 (t, 2H, J = 6.8, H C–O–C᎐O),
᎐
᎐
2
3.94 (dm, 2H, J =25.5, H2C–O–C–CH2), 2.55 (dd, 2H, J = 14.8,
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
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7.5, H2C–C), 2.50 (dd, 2H, J = 14.8, 7.5, H2C–C), 1.58 (ddm,
2H, J = 15.0, 7.3, H2C–), 1.35 (ddm, 2H, J = 15.0, 7.3, H2C–),
0.89 (t, 3H, J = 7.3, H3C–). 13C NMR (100 MHz, CDCl3) δ
172.8 (0), 134.5 (1), 132.2 (1), 118.6 (2), 116.4 (2), 82.1 (0), 65.5
(2), 64.7 (2), 38.8 (2), 30.6 (2), 19.1 (2), 13.5 (3). MS (EI) m/z (%)
253 (Mϩ ϩ 1, 100), 197 (15), 151 (15), 109 (16), 93 (20), 81 (45),
69 (46).
in Et2O (200 mL) at Ϫ70 ЊC. After addition is completed, the
mixture was warmed to 20 ЊC and stirring was continued for
1 h. The reaction was quenched by addition of methanol
(15 mL), and the solution was washed with HCl (aq) (1 M).
The aqueous layer was extracted with methyl tert-butyl ether
(MTBE) (3 times 20 mL), and the combined organic extracts
were dried with MgSO4, filtered and evaporated.
General procedure for the preparation of butenoic ketones (5)
(4S*,5R*)-4-Allyloxy-4-phenylnona-1,8-dien-5-ol
(6a).
Obtained from 5a (6.10 g, 22.6 mmol) as a colourless liquid
(3.50 g, 64%). Found: C, 79.4%; H, 8.9%. C18H24O2 requires C,
79.4%; H, 8.9%. IR (film) ν/cmϪ1 705 s, 916 s, 1069 s, 1446 m,
1640 m, 2925 m, 2979 w, 3568 brw. 1H NMR (400 MHz,
CDCl3) δ 7.35–7.15 (5H, Ph), 6.00 (dddd, 1H, J = 17.1, 10.5,
7.5, 6.3, HC–CH2–C), 5.84 (dddd, 1H, J = 17.1, 10.5, 5.3, 5.0,
HC–CH2–O), 5.62 (dddd, 1H, J = 17.1, 10.3, 6.5, 6.5, HC–
Vinylmagnesium chloride (36 mL, 1.7 M solution in THF, 61
mmol) was added to a solution of the corresponding ester 2 (20
mmol) in Et2O (100 mL) at Ϫ70 ЊC. The reaction mixture was
stirred at this temperature for 1 h and then at 20 ЊC for 12 h. The
reaction mixture was poured into saturated NH4Cl solution,
extracted with MTBE (3 times with 50 mL), dried with MgSO4,
filtered and evaporated. The residue was distilled.
CH –CH ), 5.24 (dm, 1H, J = 17.1, H C᎐CH), 5.14 (dddd, 1H,
᎐
2
2
J = 217.1, 1.5, 1.5, 1.5, H C᎐CH), 5.07 (dm, 1H, J = 10.3,
᎐
2
rac-4-Allyloxy-4-phenylnona-1,8-dien-5-one (5a). Obtained
from 2a (5.00 g, 20 mmol) as a colourless liquid (3.50 g, 64%),
bp 90 ЊC (0.08 mbar). Found: C, 80.1%; H, 8.3%. C18H22O2
requires C, 80.0%; H, 8.2%. IR (film) ν/cmϪ1 702 s, 916 s, 996 s,
1072 s, 1447 m, 1642 m, 1716 s, 2924 m, 3078 m. 1H NMR (400
MHz, CDCl3) δ 7.45–7.27 (5H, Ph), 6.00 (dddd, 1H, J = 17.3,
10.5, 5.0, 4.8, HC–CH2–O), 5.66 (dddd, 1H, J = 17.3, 10.3, 6.5,
6.5, HC–CH2–CH2), 5.59 (dddd, 1H, J = 17.3, 10.3, 7.3, 6.5,
HC–CH2–C–O), 5.45 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5,
H C᎐CH), 5.06 (dm, 1H, J = 10.3, H C᎐CH), 4.85 (dddd, 1H,
᎐
᎐
2
2
J = 17.1, 1.5, 1.5, 1.5, H C᎐CH), 4.81 (dddd, 1H, J = 10.3, 1.5,
᎐
2
1.5, 1.5, H2C᎐CH), 3.88 (dddd, 1H, J = 12.6, 5.3, 1.5, 1.5, H2C–
᎐
O), 3.69 (dm, 1H, J = 12.6, H2C–O), 3.69 (m, 1H, HC–OH),
3.05 (dd, 1H, J = 15.5, 7.5, H2C–C–O), 2.70 (dd, 1H, J = 15.5,
6.3, H2C–C–O), 2.14 (m, 1H, H2C–CH2–C–OH), 1.94 (m, 1H,
H2C–CH2–C–OH), 1.94 (brs, 1H, HO–), 1.57 (dddd, 1H,
J = 15.5, 9.0, 7.0, 1.5, H2C–C–OH), 1.03 (dddd, 1H, J = 15.5,
9.3, 5.0, 1.5, H2C–C–OH). 13C NMR (100 MHz, CDCl3)
δ 140.4 (0), 138.5 (1), 134.9 (1), 134.0 (1), 128.1 (1), 127.4 (1),
127.3 (1), 117.6 (2), 115.5 (2), 114.5 (2), 83.0 (0), 76.4 (1), 63.6
(2), 36.2 (2), 30.6 (2), 30.2 (2). MS (EI) m/z (%) 215 (Mϩ Ϫ 57,
50), 197 (70), 187 (45), 145 (25), 131 (27), 105 (100), 91 (20), 69
(20), 55 (22).
H C᎐CH), 5.24 (dddd, 1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
5.10 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C ᎐CH), 5.04 (dddd,
᎐
2
1H, J = 10.3, 1.5, 1.5, 1.5, H C᎐CH), 4.92 (dddd, 1H, J = 17.3,
᎐
2
1.5, 1.5, 1.5, H C᎐CH), 4.87 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5,
᎐
2
H C᎐CH), 4.05 (dddd, 1H, J = 12.8, 4.8, 1.5, 1.5, H C–O), 3.85
᎐
2
2
(dddd, 1H, J = 12.8, 5.0, 1.5, 1.5, H2C–O), 3.18 (dddd, 1H,
J = 15.5, 7.3, 1.5, 1.5, H2C–C–O), 2.85 (dddd, 1H, J = 15.5, 6.5,
1.5, 1.5, H2C–C–O), 2.68 (ddd, 1H, J = 15.1, 8.5, 6.5, H2C–
(4R*,5R*)- and (4R*,5S*)-4-Allyloxy-4-methylnona-1,8-dien-
5-ol (6b). Obtained from 5b (5.00 g, 24 mmol) as a colourless
liquid (5.02 g, 99%). 2:1 mixture of diastereomers. Found: C,
74.1%; H, 10.5%. C13H22O2 requires C, 74.2%; H:,10.5%. IR
(film) ν/cmϪ1 914 s, 997 m, 1066 s, 1380 w, 1641 m, 2927 m, 2979
C᎐O), 2.58 (ddd, 1H, J = 15.1, 8.5, 6.5, H C–C᎐O), 2.23
᎐
᎐
2
(dddddd, 1H, J = 18.1, 8.5, 6.5, 6.5, 1.5, 1.5, H C–CH –C᎐O),
᎐
2
2
2.14 (dddddd, 1H, J = 18.1, 8.5, 6.5, 6.5, 1.5, 1.5, H2C–CH2–
C᎐O). 13C NMR (100 MHz, CDCl3) δ 210.4 (0), 139.1 (0), 137.2
᎐
1
m, 3476 brw. H NMR (400 MHz, CDCl3) δ 5.93–5.74 (3H,
(1), 134.2 (1), 132.3 (1), 128.5 (1), 127.7 (1), 125.9 (1), 118.3 (2),
116.0 (2), 114.9 (2), 87.7 (0), 64.4 (2), 37.2 (2), 36.0 (2), 27.5 (2).
MS (EI) m/z (%) 213 (Mϩ Ϫ 57, 42), 195 (30), 187 (60), 171 (15),
145 (18), 129 (15), 105 (100), 69 (20).
HC᎐CH ), 5.24 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
5.10 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5, H2C᎐CH), 5.08–4.99
᎐
(3H, H C᎐CH), 4.94 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5,
᎐
2
H C᎐CH), 3.95–3.89 (2H, H C–O), 3.55 (ddd, 1H, J = 9.8, 3.3,
᎐
2
2
3.0, HC–OH), 2.40 (m, 1H, HO–), 2.40–2.03 (4H, H2C–), 1.60–
1.40 (2H, H2C–), 1.08 (s, 3H, H3C–). 13C NMR (100 MHz,
CDCl3) δ 138.6 (1), 135.3 (1), 133.3 (1), 117.7 (2), 115.9 (2),
114.7 (2), 79.4 (0), 74.1 (1), 62.5 (2), 38.9 (2), 30.8 (2), 30.2 (2),
17.8 (3). MS (EI) m/z (%) 153 (Mϩ Ϫ 57, 100), 135 (60), 111 (8),
95 (15), 81 (5), 70 (5). NMR-data of the minor diastereomer:
13C NMR (100 MHz, CDCl3) δ 138.6 (1), 135.5 (1), 134.3 (1),
117.3 (2), 115.6 (2), 114.7 (2), 79.0 (0), 74.8 (1), 62.5 (2), 39.1 (2),
31.0 (2), 30.3 (2), 19.0 (3).
rac-4-Allyloxy-4-methylnona-1,8-dien-5-one (5b). Obtained
from 2b (10.00 g, 50 mmol) as a colourless liquid (8.20 g, 78%),
bp 100 ЊC (0.12 mbar). Found: C, 75.0%; H, 9.6%. C13H20O2
requires C, 75.0%; H, 9.7%. IR (film) ν/cmϪ1 917 m, 996 m, 1071
w, 1716 s, 2934 w, 2981 w. 1H NMR (400 MHz, CDCl3) δ 5.94
(dddd, 1H, J = 17.1, 10.3, 5.0, 5.0, HC–CH2–O), 5.83 (dddd,
1H, J = 17.1, 10.3, 6.8, 6.3, HC–CH2–CH2), 5.72 (dddd, 1H,
J = 16.1, 11.3, 7.3, 7.0, HC–CH2–C–O), 5.34 (dddd, 1H,
J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.19 (dddd, 1H, J = 10.3, 1.5,
᎐
2
1.5, 1.5, H C᎐CH), 5.10 (dm, 1H, J = 16.1, H C᎐CH), 5.10 (dm,
᎐
᎐
2
2
rac-2-Allyloxy-2-phenylpent-4-en-1-ol (10a). Obtained from
2a (12.0 g, 49 mmol) as a colourless liquid (8.33 g, 78%), bp
90 ЊC (0.06 mbar). Found: C, 76.8%; H, 8.3%. C14H18O2
requires C, 77.0%; H, 8.3%. IR (film) ν/cmϪ1 702 s, 770 m, 919 s,
997 s, 1070 s, 1126 s, 1446 m, 1495 m, 1641 m, 2881 m, 2918 m,
2979 m, 3076 m, 3443 brm. 1H NMR (400 MHz, CDCl3)
δ 7.40–7.25 (5H, Ph), 5.93 (dddd, 1H, J = 17.3, 10.5, 5.3, 5.3,
HC–CH2–O), 5.73 (dddd, 1H, J = 17.3, 10.3, 7.0, 7.0, HC–
1H, J = 11.3, H C᎐CH), 5.06 (dm, 1H, J = 17.1, H C᎐CH), 4.98
᎐
᎐
2
(dm, 1H, J = 10.5, H C᎐CH), 3.93 (dddd, 1H, J = 212.5, 5.0, 1.5,
᎐
2
1.5, H2C–O), 3.87 (dddd, 1H, J = 12.5, 5.0, 1.5, 1.5, H2C–O),
2.74 (dd, 1H, J = 7.5, 4.5, H C–C᎐O), 2.72 (dd, 1H, J = 7.5, 4.5,
᎐
2
H C–C᎐O), 2.52 (dd, 1H, J = 14.6, 7.0, H C–C–O), 2.43 (dd,
᎐
2
2
1H, J = 14.6, 7.3, H2C–C–O), 2.31 (dm, 1H, J = 13.8, H2C–
CH –C᎐O), 2.31 (dm, 1H, J = 13.8, H C–CH –C᎐O), 1.31
᎐
᎐
2
2
2
(s, 3H, H3C–). 13C NMR (100 MHz, CDCl3) δ 213.4 (0), 137.4
(1), 134.5 (1), 132.4 (1), 118.5 (2), 116.1 (2), 115.1 (2), 84.1 (0)
64.8 (2), 40.9 (2), 36.1 (2), 27.4 (2), 20.3 (3). MS (EI) m/z (%)
209 (Mϩ ϩ 1, <5), 191 (12), 151 (100), 133 (20), 125 (15), 109
(12), 95 (15), 81 (18).
CH –C), 5.32 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.16
᎐
2
2
(dddd, 1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH), 5.12 (dddd, 1H,
᎐
2
J = 17.3, 1.5, 1.5, 1.5, H2C᎐CH), 5.07 (dddd, 1H, J = 10.3, 1.5,
᎐
1.5, 1.5, H C᎐CH), 3.85 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5, H C–
᎐
2
2
O–C), 3.84 (d, 2H, J = 6.5, H2C–OH), 3.78 (dddd, 1H, J = 12.3,
5.3, 1.5, 1.5, H2C–O–C), 2.77 (dddd, 1H, J = 14.6, 7.0, 1.5, 1.5,
H2C–C), 2.71 (dddd, 1H, J = 14.6, 7.0, 1.5, 1.5, H2C–C), 1.96
(t, 1H, J = 6.5, HO–). 13C NMR (100 MHz, CDCl3) δ 141.1 (0),
134.8 (1), 133.1 (1), 128.3 (1), 127.4 (1), 126.4 (1), 118.2 (2),
General procedure for the preparation of alcohols 6 and 10
DIBAL-H (19 mL, 107 mmol) was added dropwise to a solu-
tion of the corresponding ester (50 mmol) or ketone (90 mmol)
2920
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925

View Online
116.1 (2), 81.0 (0), 65.6 (2), 63.5 (2), 39.5 (2). MS (EI) m/z (%)
161 (Mϩ Ϫ 57, 10), 142 (20), 131 (100), 116 (35), 105 (20), 91
(72), 65 (22), 51 (11).
(1), 127.7 (1), 127.5 (1), 127.3 (1), 118.3 (2), 118.1 (2), 116.0 (2),
82.1 (0), 77.1 (1), 63.8 (2), 36.7 (2). MS (EI) m/z (%) 203
(Mϩ Ϫ 41, <5), 187 (100), 169 (33), 145 (22), 117 (23), 105 (95),
69 (28), 55 (15). NMR data for the minor diastereomer (partial
1
overlapping of signals with the major isomer): H NMR (400
rac-2-Allyloxy-2-methylpent-4-en-1-ol (10b). Obtained from
2b (3.20 g, 16 mmol) as a colourless liquid (2.50 g, 99%). IR
(film) ν/cmϪ1 917 s, 999 m, 1055 s, 1125 m, 2873 m, 2931 m, 2978
MHz, CDCl3) δ 7.37–7.26 (5H, Ph), 6.09 (dddd, 1H, J = 17.1,
10.3, 6.8, 6.5, HC᎐CH ), 4.00 (dddd, 1H, J = 13.1, 5.3, 1.5, 1.5,
᎐
2
H2C–O), 3.81 (dddd, 1H, J = 13.1, 4.8, 1.5, 1.5, H2C–O), 3.12
(ddm, 1H, J = 15.3, 7.5, H2C–C), 2.78 (ddm, 1H, J = 15.3, 6.5,
H2C–C), 2.72 (brs, 1H, HO–). 13C NMR (100 MHz, CDCl3):
δ = 140.0 (0), 135.8 (1), 134.8 (1), 133.9 (1), 127.9 (1), 127.5 (1),
127.3 (1), 117.8 (2), 116.3 (2), 115.5 (2), 83.0 (0), 77.6 (1), 63.7
(2), 36.5 (2).
1
m, 3427 brm. H NMR (400 MHz, CDCl3) δ 5.82 (dddd, 1H,
J = 17.1, 10.3, 5.3, 5.3, HC–CH2–O), 5.71 (dddd, 1H, J = 17.1,
10.3, 7.3, 7.3, HC–CH2–C), 5.19 (dddd, 1H, J = 17.1, 1.5, 1.5,
1.5, H C᎐CH), 5.04 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5,
᎐
2
H C᎐CH), 5.00 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
5.00 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5, H C᎐CH), 3.86 (d, 2H,
᎐
2
J = 5.3, H2C–O), 3.40 (d, 1H, J = 11.5, H2C–OH), 3.35 (d, 1H,
J = 11.5, H2C–OH), 2.41 (brs, 1H, HO–), 2.25 (dddd, 1H,
J = 15.8, 7.3, 1.5, 1.5, H2C–C), 2.21 (dddd, 1H, J = 15.8, 7.3,
1.5, 1.5, H2C–C), 1.17 (s, 3H, H3C–). 13C NMR (100 MHz,
CDCl3) δ 135.3 (1), 133.5 (1), 117.7 (2), 115.8 (2), 77.1 (0), 66.9
(2), 62.6 (2), 39.8 (2), 19.5 (2). MS (EI) m/z (%) 125 (Mϩ Ϫ 31,
10), 115 (12), 99 (95), 81 (100), 69 (28), 57 (15).
(3S*,4S*)- and (3S*,4R*)-4-Allyloxy-4-methylhepta-1,6-dien-
3-ol (8b). Obtained from 2b (10.00 g, 50 mmol) as a mixture of
two diastereomers (dr = 1.8:1). After distillation (bp 90 ЊC/0.08
mbar) 8b was isolated as a colourless liquid, yield: 7.20 g (78%).
Found: C, 72.4%; H, 10.0%. C11H18O2 requires C, 72.5%; H,
10.0%. IR (film) ν/cmϪ1 919 s, 996 s, 1065 s, 1129 m, 1378 m,
1423 m, 1458 m, 2981 m, 3464 brm. 1H NMR (400 MHz,
CDCl ) δ 5.95–5.76 (3H, HC᎐CH ), 5.32 (dm, 1H, J = 17.5,
᎐
3
2
rac-2-Allyloxy-2-allylpent-4-en-1-ol (10c). Obtained from 2c
(1.75 g, 6.9 mmol) as a colourless liquid (1.23 g, 97%). Found:
C, 71.9%; H, 9.8%. C11H18O2 requires C, 72.5%; H, 9.9%. IR
(film) ν/cmϪ1 916 s, 1071 s, 1439 m, 1640 s, 2925 m, 3076 m, 3445
s. H NMR (400 MHz, CDCl3) δ 5.84 (ddt, 1H, J = 17.3, 10.3,
5.3, HC–CH2–O), 5.76 (ddt, 2H, J = 17.1, 10.3, 7.3, HC–CH2–
H C᎐CH), 5.25 (dm, 1H, J = 17.1, H C᎐CH), 5.20 (dm, 1H,
᎐
᎐
2
2
J = 10.5, H C᎐CH), 5.12–5.01 (3H, H C᎐CH), 4.07 (d, 1H,
᎐
᎐
2
2
J = 5.8, HC–OH), 3.96 (d, 2H, J = 5.0, H2C–O), 2.59, 2.46 (s,
1H, HO–), 2.43 (dd, 1H, J = 14.8, 7.0, H2C–C), 2.36 (dd, 1H,
J = 14.8, 7.5, H2C–C), 2.25 (dd, 1H, J = 14.8, 7.5, H2C–C), 2.17
(dd, 1H, J = 14.8, 7.0, H2C–C), 1.13, 1.09 (s, 3H, H3C–). 13C
NMR (100 MHz, CDCl3) δ 136.4 (1), 135.8 (1), 135.3 (1), 135.1
(1), 134.1 (1), 133.2 (1), 118.0 (2), 117.7 (2), 117.5 (2), 116.9 (2),
116.0 (2), 155.7 (2), 79.0 (0), 78.8 (0), 76.7 (1), 76.2 (1), 62.7 (2),
62.7 (2), 39.2 (2), 38.9 (2), 19.0 (3), 17.9 (3). MS (EI) m/z (%)
165 (Mϩ Ϫ 17, <5), 141 (8), 125 (100), 107 (60), 95 (20), 81 (22),
69 (18), 55 (78).
1
C), 5.22 (dddd, 1H, J = 17.1, 1.8, 1.8, 1.8, H C᎐CH), 5.10–5.01
᎐
2
(3H, H C᎐CH), 3.92 (ddd, 1H, J = 5.3, 1.5, 1.5, OCH -
᎐
2
2
CH᎐CH), 3.44 br (d, 2H, J = 4.3, –CH OH), 2.31 (dd, 2H,
᎐
2
J = 14.3, 7.3, CHHCH᎐CH ), 2.22 (dd, 1H, J = 14.3, 7.3,
᎐
2
CHHCH᎐CH ), 2.05 br (t, 1H, J = 4.3, H C–OH). 13C NMR
᎐
2
2
(100 MHz, CDCl3) δ 135.0 (1), 133.1 (1), 118.1 (2), 116.0 (2),
78.7 (0), 64.5 (2), 62.4 (2), 37.3 (2). MS (EI) m/z (%) 125
(Mϩ Ϫ 57, 60), 107 (100), 81 (95).
rac-2-Allyloxy-2-phenylpent-4-enal (11a).
A solution of
alcohol 10a (5.00 g, 22.9 mmol) in DCM (20 mL) was added
dropwise to a suspension of PDC (12.93 g, 34.3 mmol) in DCM
(80 mL). The mixture was stirred at 20 ЊC for 24 hours, filtered
and evaporated. The residue was dissolved in ether (100 mL)
and filtered through a 10 cm pad of silica. The organic layer
was subsequently washed with ice-cold diluted HCl (aq),
NaHCO3 (aq) and brine, dried with MgSO4, filtered, evapor-
ated and purified by Kugelrohr distillation at 140 ЊC (0.13
mbar) to give 11a as a colourless liquid. Yield: 3.33 g (67%). IR
(film) ν/cmϪ1 706 s, 929 m, 990 s, 1071 m, 1732 s, 2809 w, 3079 w.
1H NMR (400 MHz, CDCl3) δ 9.48 (s, 1H, –CHO), 7.35–7.18
(5H, Ph), 5.87 (dddd, 1H, J = 17.3, 10.3, 5.3, 5.3, HC–CH2–O),
5.56 (dddd, 1H, J = 17.3, 10.3, 7.0, 6.8, HC–CH2–C), 5.29
General procedure for the preparation of alcohols 8
Under an atmosphere of dry argon, DIBAL-H (8.1 mL, 45
mmol) was slowly added to a solution of the ester 2 (41 mmol)
in ether at Ϫ90 ЊC. The reaction mixture was stirred at Ϫ70 ЊC
for 30 min, and then vinylmagnesium chloride (36 mL 1.7 M
solution in THF, 61 mmol) was added. The reaction mixture
was allowed to warm to 20 ЊC, and stirring was continued for
12 h. The mixture was hydrolyzed with diluted hydrochloric
acid (1 M), extracted with ether, and then dried with MgSO4.
The solvent was evaporated and the crude product purified by
column chromatography on silica (using cyclohexane–MTBE
mixture (20:1) as eluent) or by distillation.
(dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.11 (dddd, 1H,
J = 10.3, 1.5, 1.5, 1.5, H C᎐CH), 5.03 (dddd, 1H, J = 17.3, 1.5,
᎐
2
᎐
2
(3S*,4R*)-4-Allyloxy-4-phenylhepta-1,6-dien-3-ol
(8a).
Obtained from 2a (10.00 g, 41 mmol) as a mixture of two
diastereomers (dr = 2.4:1). After removal of the minor dias-
tereomer by chromatography (3S*,4R*)-8a was isolated as a
colourless liquid, yield: 5.00 g (50%). Found: C, 78.7%; H,
8.3%. C16H20O2 requires C, 78.7%; H, 8.3%. IR (film) ν/cmϪ1
706 s, 920 s, 1069 s, 1233 m, 1446 m, 1732 m, 3077 m, 3512 brm.
1H NMR (400 MHz, CDCl3) δ 7.37–7.26 (5H, Ph), 6.01–5.90
1.5, 1.5, H C᎐CH), 4.98 (dddd, 1H, J = 10.3, 1.3, 1.3, 1.3,
᎐
2
H C᎐CH), 3.92 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5, H C–O–C),
᎐
2
2
3.87 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5, H2C–O–C), 2.96 (ddm,
1H, J = 15.1, 7.0, H2C–C), 2.78 (ddm, 1H, J = 15.1, 7.0, H2C–
C). 13C NMR (100 MHz, CDCl3) δ 200.1 (0), 136.4 (0), 134.1
(1), 131.5 (1), 128.7 (1), 128.2 (1), 126.7 (1), 118.8 (2), 116.7 (2),
85.9 (0), 64.7 (2), 36.4 (2). MS (EI) m/z (%) 217 (Mϩ ϩ 1, 30),
187 (70), 131 (80), 105 (100).
(2H, HC᎐CH ), 5.39 (ddd, 1H, J = 17.5, 10.3, 7.0, HC–CH–
᎐
2
OH), 5.32 (dddd, 1H, J = 17.5, 1.5, 1.5, 1.5, H C᎐CH), 5.22
᎐
2
(dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH), 5.19 (dddd, 1H,
᎐
2
General procedure for the preparation of tetraenes 7, 9, 12
J = 17.5, 1.5, 1.5, 1.5, H C᎐CH), 5.18 (dddd, 1H, J = 10.3, 1.5,
᎐
2
1.5, 1.5, H C᎐CH), 5.19 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5,
NaH (0.35 g, 60% dispersion in mineral oil, 8.8 mmol) was
slowly added to a solution of the corresponding alcohol (7.3
mmol) in THF (50 mL) and heated to reflux for 1 h. Allyl
bromide (1.0 mL, 11.0 mmol) was added and the reaction mix-
ture was again refluxed for 1 h. After cooling to ambient tem-
perature water (100 mL) was added and the solution was
extracted with MTBE (3 times 50 mL). The combined organic
᎐
2
H C᎐CH), 5.11 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
4.41 (dm, 1H, J = 7.0, HC–OH), 3.97 (dddd, 1H, J = 12.3, 5.8,
1.5, 1.5, H2C–O), 3.83 (dddd, 1H, J = 12.3, 5.3, 1.5, 1.5, H2C–
O), 2.94 (ddm, 1H, J = 15.5, 7.0, H2C–C), 2.83 (dddd, 1H,
J = 15.5, 5.5, 1.5, 1.5, H2C–C), 2.73 (d, 1H, J = 2.5, HO–). 13C
NMR (100 MHz, CDCl3) δ 139.0 (0), 135.7 (1), 134.6 (1), 133.1
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
2921

View Online
layers were dried with MgSO4, filtered and evaporated. The
residue was purified by flash chromatography on silica to give
the corresponding tetraene as a colourless liquid.
CDCl3) δ 140.3 (0), 135.2 (1), 135.0 (1), 134.7 (1), 133.7 (1),
127.8 (1), 127.4 (1), 126.8 (1), 119.0 (2), 118.1 (2), 115.9 (2),
115.0 (2), 82.9 (1), 82.5 (0), 69.4 (2), 63.6 (2), 38.8 (2). MS (EI)
m/z (%) 227 (Mϩ Ϫ 57, <5), 187 (30), 169 (15), 157 (15), 145
(20), 129 (15), 117 (20), 105 (100), 91 (18), 81 (18), 69 (30), 55
(20).
[(1S*,2R*)-1-Allyl-1,2-bis(allyloxy)hex-5-enyl]benzene (7a).
Obtained from alcohol 6a (2.00 g, 7.3 mmol). Yield: 2.20 g
(96%). Found: C, 81.0%; H, 9.1%. C21H28O2 requires C, 80.7%;
H, 9.0%. IR (film) ν/cmϪ1 704 s, 916 s, 994 m, 1070 s, 1096 m,
(3R*,4R*)- and (3R*,4S*)-3,4-Bis(allyloxy)4-methylhepta-
1,6-diene (9b). Obtained from 8b (2.40 g, 13.2 mmol) as a mix-
ture of two diastereomers (dr = 1.8:1). Yield: 1.80 g (61%).
Found: C, 75.8%, H: 9.9%. C14H22O2 requires C, 75.6%; H,
10.0%. IR (film) ν/cmϪ1 917 s, 995 m, 1074 s, 1128 m, 1641 w,
1
1132 m, 1446 w, 2860 w, 3076 w. H NMR (400 MHz, CDCl3)
δ 7.43–7.38 (2H, Ph), 7.35–7.30 (2H, Ph), 7.28–7.22 (1H, Ph),
6.06–5.89 (3H, HC᎐CH ), 5.71 (dddd, 1H, J = 17.3, 10.3, 7.0,
᎐
2
6.3, HC᎐CH ), 5.35 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5,
᎐
2
1
2862 w, 2980 m, 3078 w. H NMR (400 MHz, CDCl3) δ 5.92–
H C᎐CH ), 5.28 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH),
᎐
᎐
2
2
2
5.75 (4H, HC᎐CH ), 5.23 (dddd, 1H, J = 17.3, 2.0, 2.0, 2.0,
5.19 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.18–5.11
᎐
2
᎐
2
H C᎐CH), 5.23 (dddd, 1H, J = 17.3, 2.0, 2.0, 2.0, H C᎐CH),
(3H, H C᎐CH), 4.94 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5,
᎐
᎐
2
2
᎐
2
5.22 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.12 (dddd,
H C᎐CH), 4.90 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5, H C᎐CH),
᎐
2
᎐
᎐
2
2
1H, J = 10.3, 1.5, 1.5, 1.5, H C᎐CH), 5.08–5.01 (3H, H C᎐CH),
4.24 (dddd, 1H, J = 12.8, 5.3, 1.5, 1.5, H2C–O), 4.16 (dddd, 1H,
J = 12.8, 5.3, 1.5, 1.5, H2C–O), 3.96 (dddd, 1H, J = 12.8, 5.0,
1.5, 1.5, H2C–O), 3.84 (dddd, 1H, J = 12.8, 4.5, 1.5, 1.5, H2C–
O), 3.57 (dd, 1H, J = 9.3, 2.8, HC–O), 3.13 (ddm, 1H, J = 15.6,
7.5, H2C–C), 2.82 (dd, 1H, J = 15.6, 5.8, H2C–C), 2.12 (dm,
1H, J = 15.1, H2C–CH2–CH), 2.02 (dm, 1H, J = 15.1, H2C–
CH2–CH), 1.66 (dddd, 1H, J = 14.1, 9.3, 6.8, 2.8, H2C–CH–C),
1.16 (dddd, 1H, J = 14.3, 9.3, 9.3, 5.3, H2C–CH–C). 13C NMR
(100 MHz, CDCl3) δ 141.0 (0), 138.8 (1), 135.3 (1), 135.1 (1),
134.3 (1), 127.6 (1), 127.5 (1), 126.9 (1), 117.5 (2), 115.9 (2),
115.1 (2), 114.5 (2), 83.5 (0), 83.0 (1), 73.7 (2), 63.1 (2), 37.2 (2),
30.9 (2), 30.1 (2). MS (EI) m/z (%) 255 (Mϩ Ϫ 57, 28), 197 (100),
187 (90).
᎐
᎐
2
2
4.97 (dm, 1H, J = 10.3, H C᎐CH), 4.09–3.95 (3H, H C–O), 3.77
᎐
2
2
(dddd, 1H, J = 12.8, 1.5, 1.5, 1.5, H2C–O), 3.68 (d, 1H, J = 7.0,
HC–O), 2.48 (dd, 1H, J = 14.5, 7.3, H2C–C), 2.27 (dd, 1H,
J = 14.5, 7.3, H2C–C), 1.13 (s, 3H, H3C–). 13C NMR (100 MHz,
CDCl3) δ 135.8 (1), 135.0 (1), 134.9 (1), 134.2 (1), 118.3 (2),
117.4 (2), 116.8 (2), 115.3 (2), 83.8 (0), 78.4 (0), 69.8 (2), 63.2 (2),
40.2 (2), 18.0 (3). MS (EI) m/z (%) 165 (Mϩ Ϫ 57, 18), 125 (30),
107 (55), 95 (37), 81 (54), 55 (100). NMR data of the minor
1
diastereomer: H NMR (400 MHz, CDCl3) δ 5.65 (dddd, 1H,
J = 17.1, 10.0, 7.0, 7.0, HC᎐CH ), 3.62 (d, 1H, J = 7.8, HC–O),
᎐
2
2.56 (dd, 1H, J = 14.5, 7.0, H2C–C), 1.24 (s, 3H, H3C–). 13C
NMR (100 MHz, CDCl3) δ 136.1 (1), 136.0 (1), 135.1 (1), 134.8
(1), 117.4 (2), 116.3 (2), 116.2 (2), 115.6 (2), 85.4 (0), 78.5 (0),
69.7 (2), 63.8 (2), 39.8 (2), 20.4 (3).
(4S*,5S*)- and (4R*,5S*)-4,5-Bis(allyloxy)4-methylnona-1,8-
diene (7b). Obtained from 6b (3.20 g, 15.2 mmol) as a 2:1
mixture of diastereomers after chromatography. Yield: 2.20 g
(58%). Found: C, 76.9%; H, 10.5%. C16H26O2 requires C, 76.8%;
H, 10.5%. IR (film) ν/cmϪ1 914 s, 1072 m, 1095 m, 1130 m, 1641
4,4-Bis(allyloxy)methylhepta-1,6-diene (12c). Obtained from
10c (1.20 g, 6.6 mmol). Yield: 0.87 g (59%). IR (film) ν/cmϪ1
1
811 s, 916 s, 1090 s, 1640 m, 2861 s, 3077 s. H NMR (400
1
MHz, CDCl ) δ 5.95–5.75 (4H, –HC᎐CH ), 5.27–5.03 (8H,
᎐
3
2
m, 2858 m, 2928 m, 2979 m, 3077 m. H NMR (400 MHz,
–HC᎐CH ), 4.01 (ddd, 2H, J = 5.3, 1.5, 1.5, –OCH CH᎐CH ),
᎐
᎐
2
2
2
CDCl ) δ 5.96–5.74 (4H, HC᎐CH ), 5.24 (dddd, 1H, J = 17.1,
᎐
3
2
3.94 (ddd, 2H, J = 5.4, 1.5, 1.5, –OCH CH᎐CH ), 3.33 (s, 2H,
᎐
2
2
1.5, 1.5, 1.5, H C᎐CH ), 5.13–5.02 (5H, H C᎐CH), 5.01 (dddd,
᎐
᎐
2
2
2
H COCH –), 2.33 (d, 4H, J = 7.0, H C–CH᎐CH ). 13C NMR
᎐
2
2
2
2
1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH), 4.94 (dm, 1H, J = 10.0,
᎐
2
(100 MHz, CDCl3) δ 135.6 (1), 134.9 (1), 133.7 (1), 117.8 (2),
116.7 (2), 115.7 (2), 78.2 (0), 72.3 (2), 72.2 (2), 63.0 (2), 38.0 (2).
MS (EI) m/z (%) 223 (Mϩ ϩ 1, 5), 107 (40), 95 (50), 81 (100).
H C᎐CH), 4.17 (dddd, 1H, J = 12.6, 5.5, 1.5, 1.5, H C–O),
᎐
2
2
4.09–3.87 (3H, H2C–O), 3.26 (dd, 1H, J = 9.8, 2.0, HC–O), 2.44
(ddm, 1H, J = 14.8, 7.0, H2C–), 2.33–2.23 (2H, H2C–), 2.08
(ddm, 1H, J = 14.8, 7.3, H2C–), 1.65 (dddm, 1H, J = 13.8, 7.0,
2.3, H2C–), 1.52 (dddm, 1H, J = 13.8, 9.3, 5.3, H2C–), 1.15
(s, 3H, H3C–). 13C NMR (100 MHz, CDCl3) δ 138.7 (1), 135.9
(1), 135.5 (1), 134.2 (1), 117.2 (2), 115.9 (2), 115.2 (2), 114.7 (2),
84.1 (1), 80.0 (0), 74.0 (1), 63.1 (2), 39.6 (2), 30.9 (2), 30.0 (2),
19.7 (3). MS (EI) m/z (%) 193 (Mϩ Ϫ 57, 80), 165 (10), 151 (20),
135 (30), 125 (45), 115 (50), 95 (40), 81 (100), 67 (76), 55 (56).
NMR-data of the minor diastereomer (obtained from the mix-
General procedure for the ring closing metathesis reaction
Method A. Grubbs’ catalyst (A) (50 mg, 3 mol% except
otherwise stated for the individual compounds) was added to a
solution of the metathesis precursor (2.0 mmol) in DCM (10
mL) and the mixture was stirred at 20 ЊC for 12 h. For double
ring closing metathesis of tetraenes 7, 9 and 12, 8 mol% of
catalyst A were employed. The solvent was evaporated and the
crude dihydropyrans purified by flash chromatography on silica
using hexanes–MTBE mixtures as eluent, or by Kugelrohr
distillation. Method B. Complex B (34 mg, 3 mol%) was added
to a solution of the metathesis precursor (1.2 mmol) in toluene
(10 mL) and the mixture was heated to reflux for 2 hours. The
solvent was evaporated and the crude product was purified by
flash chromatography or Kugelrohr distillation.
1
ture): H NMR (400 MHz, CDCl3) δ 2.33 (ddm, 1H, J = 14.5,
7.0, H2C–), 1.76 (ddm, 1H, J = 13.8, 6.5, H2C–). 13C NMR (100
MHz, CDCl3) δ 138.9 (1), 135.7 (1), 135.3 (1), 134.4 (1), 117.3
(2), 115.9 (2), 115.3 (2), 114.6 (2), 82.8 (1), 79.4 (0), 73.5 (2), 62.7
(2), 40.1 (2), 31.2 (2), 29.8 (2), 18.7 (3).
(1S*,2R*)-[1-Allyl-1,2-bis(allyloxy)but-3-enyl]benzene (9a).
Obtained from (3S*,4R*)-8a (2.70 g, 11.0 mmol). Yield: 2.00 g
(64%). Found: C, 80.4%, H: 8.6%. C19H24O2 requires C, 80.2%;
H, 8.5%. IR (film) ν/cmϪ1 712 m, 919 s, 994 m, 1072 s, 1124 m,
rac-2-Phenyl-3,6-dihydro-2H-pyran-2-carboxylic acid methyl
ester (13a). Obtained from 2a, (0.50 g, 2.0 mmol) as a colourless
solid (0.40 g, 90%), mp 69 ЊC. Purification by Kugelrohr distill-
ation at 175 ЊC (0.11 mbar). Found: C, 71.7%; H, 6.5%.
C13H14O3 requires C, 71.5%; H, 6.5%. IR (KBr disk) ν/cmϪ1 673
s, 699 s, 726 s, 765 s, 1053 s, 1096 s, 1197 s, 1221 s, 1267 s, 1449 s,
1
1422 w, 1446 w, 2865 w, 2982 w, 3077w. H NMR (400 MHz,
CDCl3) δ 7.39–7.22 (5H, Ph), 5.95 (ddm, 1H, J = 17.3, 10.3,
HC᎐CH ), 5.94–5.80 (2H, HC᎐CH ), 5.55 (ddd, 1H, J = 17.5,
᎐
᎐
2
2
10.3, 7.3, HC᎐CH ), 5.38 (dddd, 1H, J = 17.3, 1.7, 1.7, 1.7,
᎐
2
1
H C᎐CH), 5.24 (dddd, 1H, J = 10.3, 1.7, 1.7, 1.7, H C᎐CH),
1732 s, 2862 m, 2935 m. H NMR (400 MHz, CDCl3) δ 7.59–
᎐
᎐
2
2
5.22 (dddd, 1H, J = 17.3, 1.7, 1.7, 1.7, H C᎐CH), 5.18 (dddd,
7.53 (2H, Ph), 7.40–7.27 (3H, Ph), 5.91 (dm, 1H, J = 10.3, H4/
H5), 5.74 (dm, 1H, J = 10.3, H4/H5), 4.51 (ddddd, 1H, J = 17.0,
2.5, 2.5, 2.5, 2.5, H6), 4.29 (ddddd, 1H, J = 17.0, 2.5, 2.5, 2.5,
2.5, H6), 3.71 (s, 3H, H3C–), 3.09 (ddddd, 1H, J = 17.1, 2.5, 2.5,
2.5, 2.5, H3), 2.58 (ddddd, 1H, J = 17.1, 2.5, 2.5, 2.5, 2.5, H3).
᎐
2
1H, J = 10.0, 1.7, 1.7, 1.7, H C᎐CH), 5.17–5.10 (4H, H C᎐CH),
᎐
᎐
2
2
4.04–3.96 (4H, H2C–O, HC–O), 3.81 (dddd, 1H, J = 13.1, 5.5,
1.7, 1.7, H2C–O), 3.12 (dd, 1H, J = 14.8, 7.3, H2C–C), 2.72
(dddd, 1H, J = 14.8, 6.3, 1.7, 1.7, H2C–C). 13C NMR (100 MHz,
2922
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925

View Online
13C NMR (100 MHz, CDCl3) δ 172.7 (0), 140.2 (0), 128.4 (1),
127.9 (1), 125.7 (1), 125.1 (1), 122.4 (1), 78.6 (0), 63.3 (2), 52.5
(3), 32.3 (2). MS (EI) m/z (%) 219 (Mϩ ϩ 1, <5), 201 (34), 169
(20), 159 (70), 105 (100), 77 (30), 51 (22).
1H, J = 18.3, H C–C᎐O), 2.64 (dm, 1H, J = 18.3, H C–C᎐O),
᎐ ᎐
2 2
2.26 (dm, 1H, J = 13.8, H C–CH –C᎐O), 2.23 (dm, 1H,
᎐
2
2
J = 13.8, H C–CH –C᎐O), 1.95 (dm, 1H, J = 17.3, H3), 1.58 (m,
᎐
2
2
1H, H3), 1.38 (s, 3H, H3C–). 13C NMR (100 MHz, CDCl3)
δ 212.6 (0), 137.3 (1), 124.8 (1), 122.6 (1), 115.0 (2), 78.7 (0), 62.0
(2), 40.8 (2), 35.1 (2), 31.1 (2), 21.7 (3). GC-MS (EI) m/z (%) 181
(Mϩ ϩ 1, 20), 163 (18), 145 (10), 127 (15), 97 (100), 81 (20), 55
(15).
rac-2-Methyl-3,6-dihydro-2H-pyran-2-carboxylic acid ethyl
ester (13b). Obtained from 2b (0.60 g, 3.0 mmol) as a colourless
liquid (0.49 g, 95%). Purification by Kugelrohr distillation at
130 ЊC (0.07 mbar). Found: C, 63.6%; H, 8.3%. C9H14O3
requires C, 63.5%; H, 8.3%. IR (film) ν/cmϪ1 1015 m, 1092 s,
(1R*)-1-((S*)-2-Phenyl-3,6-dihydro-2H-pyran-2-yl)pent-4-en-
1-ol (15a). Obtained from 6a (0.60 g, 2.2 mmol) along with a
20% admixture of cycloheptene 20 as a colourless liquid (0.35
g, 65%). Found: C, 78.7%; H, 8.3%. C16H20O2 requires C,
78.7%; H, 8.3%. IR (film) ν/cmϪ1 701 s, 915 m, 1015 s, 1093 s,
1
1192 s, 1287 m, 1448 w, 1736 s, 2901 w, 2936 w, 2983 m. H
NMR (400 MHz, CDCl3) δ 5.77 (dm, 1H, J = 10.3, H4/H5),
5.68 (dm, 1H, J = 10.3, H4/H5), 4.45 (ddddd, 1H, J = 17.1, 2.5,
2.5, 2.5, 2.5, H6), 4.21 (q, 2H, J = 7.0, H2C–CH3), 4.21 (ddddd,
1H, J = 17.1, 2.5, 2.5, 2.5, 2.5, H6), 2.65 (ddddd, 1H, J = 17.1,
2.5, 2.5, 2.5, 2.5, H3), 2.05 (ddddd, 1H, J = 17.1, 2.5, 2.5, 2.5,
2.5, H3), 1.45 (s, 3H, H3C–C), 1.28 (t, 3H, J = 7.0, H3C–CH2).
13C NMR (100 MHz, CDCl3) δ 173.9 (0), 125.1 (1), 122.3 (1),
74.6 (0), 62.9 (2), 60.9 (2), 32.7 (2), 25.2 (3), 14.1 (3). MS (EI)
m/z (%) 171 (Mϩ ϩ 1, 30), 153 (10), 141 (12), 97 (100), 81 (8), 53
(6).
1
1262 m, 1449 s, 2844 m, 2924 m, 3476 brm. H NMR (400
MHz, CDCl3) δ 7.45–7.26 (5H, Ph), 5.94 (dm, 1H, J = 10.3, H4/
H5), 5.63 (dddd, 1H, J = 17.1, 10.3, 6.8, 6.8, HC᎐CH ), 5.49
᎐
2
(dm, 1H, J = 10.3, H4/H5), 4.88 (dm, 1H, J = 17.1, H C᎐CH),
᎐
2
4.85 (dm, 1H, J = 10.3, H C᎐CH), 4.10 (ddd, 1H, J = 16.8, 5.3,
᎐
2
1.5, H6), 3.78 (dm, 1H, J = 16.8, H6), 3.74 (dd, 1H, J = 10.3,
1.5, HC–OH), 3.15 (brs, 1H, HO–), 2.85 (dm, 1H, J = 17.8,
H3), 2.53 (ddd, 1H, J = 17.8, 6.0, 1.5, H3), 2.23 (dm, 1H,
J = 15.8, H2C–CH2–CH), 1.92 (dm, 1H, J = 15.8, H2C–CH2–
CH), 1.32 (dddd, 1H, J = 13.6, 10.3, 9.3, 5.0, H2C–CH), 1.08
(dddd, 1H, J = 13.6, 9.3, 6.8, 1.5, H2C–CH). 13C NMR (100
MHz, CDCl3) δ 139.4 (0), 138.2 (1), 128.2 (1), 127.5 (1), 127.4
(1), 125.6 (1), 123.1 (1), 114.5 (2), 79.2 (0), 77.9 (1), 61.6 (2), 30.4
(2), 28.7 (2), 23.2 (2). MS (EI) m/z (%) 227 (Mϩ Ϫ 17, 40), 209
(22), 173 (57), 159 (100), 145 (35), 105 (58), 77 (18). Selected
NMR-data of cycloheptene 20 (obtained from the mixture): 1H
NMR (400 MHz, CDCl3) δ 5.26 (dddd, 1H, J = 17.3, 1.5, 1.5,
rac-2-Allyl-3,6-dihydro-2H-pyran-2-carboxylic butyl ester
(13c). Obtained from 2c (0.70 g, 2.8 mmol) as a colourless liquid
(0.45 g, 72%). Purification by Kugelrohr distillation at 120 ЊC
(0.07 mbar). Found: C, 69.8%; H, 9.0%. C13H20O3 requires C,
69.6%; H, 9.0%. IR (film) ν/cmϪ1 919 w, 1093 m, 1183 s, 1740 s,
2911 m, 2934 m, 2960 m. 1H NMR (400 MHz, CDCl3)
δ 5.75 (dddd, 1H, J = 16.1, 10.8, 7.3, 7.3, HC᎐CH ), 5.68
᎐
2
(ddddd, 1H, J = 10.5, 2.3, 2.3, 2.3, 2.3, H4/H5), 5.60 (dm, 1H,
J = 10.5, H4/H5), 5.02 (dm, 1H, J = 10.8, H C᎐CH), 5.01 (dm,
᎐
2
1H, J = 16.1, H C᎐CH), 4.38 (ddddd, 1H, J = 17.1, 2.3, 2.3, 2.3,
1.5, H C᎐CHCHHO), 5.11 (dddd, 1H, J = 10.3, 1.5, 1.5, 1.5,
᎐
2
᎐
2
2.3, H6), 4.05 (t, 2H, J = 6.8, H C–O–C᎐O), 4.03 (dm, 1H,
H C᎐CHCHHO), 4.03 (dd, 1H, J = 7.5, 2.0, HCOH), 3.63
᎐
᎐
2
2
J = 17.1, H6), 2.50 (dm, 1H, J = 17.1, H3), 2.41 (dm, 2H,
J = 7.3, H2C–C), 2.13 (ddddd, 1H, J = 17.1, 2.3, 2.3, 2.3, 2.3,
H3), 1.55 (ddm, 2H, J = 15.0, 6.8, H2C), 1.30 (ddm, 2H,
J = 15.3, 7.3, H2C), 0.85 (t, 3H, J = 7.3, H3C). 13C NMR (100
MHz, CDCl3) δ 172.8 (0), 131.9 (1), 125.3 (1), 122.0 (1), 118.4
(2), 77.3 (0), 64.6 (2), 62.9 (2), 43.2 (2), 31.1 (2), 30.5 (2), 19.0
(2), 13.5 (3). MS (EI) m/z (%) 225 (Mϩ ϩ 1, 42), 207 (8), 169 (7),
151 (5), 123 (100), 105 (10), 95 (65), 81 (20), 69 (18), 53 (18).
(dddd, 1H, J = 12.5, 5.3, 1.5, 1.5, OCHHCH᎐CH ). 13C NMR
᎐
2
(100 MHz, CDCl3) δ 142.0 (0), 135.0 (1), 133.4 (1), 128.1 (1),
127.5 (1), 127.3 (1), 125.3 (1), 115.6 (2), 81.8 (0), 78.4 (1), 63.5
(2), 31.4 (2), 28.7 (2), 22.1 (2).
(1R*)- and (1S*)-1-((R*)-2-Methyl-3,6-dihydro-2H-pyran-2-
yl)pent-4-en-1-ol (15b). Obtained from 6b (0.60 g, 2.9 mmol
of a 2:1 mixture of diastereomers) as a colourless liquid. The
minor diastereomer was removed by column chromatography.
Yield: 0.22 g, (42%). Found: C, 72.6%; H, 10.0%. C11H18O2
requires C, 72.5%; H, 10.0%. IR (film) ν/cmϪ1 653 m, 912 m,
1018 w, 1092 s, 1192 w, 1377 w, 2836 m, 2934 m, 2977 m, 3476
rac-1-(2-Phenyl-3,6-dihydro-2H-pyran-2-yl)pent-4-en-1-one
(14a). Obtained from 5a (0.60 g, 2.2 mmol) and A (180 mg, 10
mol%) as a colourless liquid (0.40 g, 74%). Found: C, 78.7%; H,
7.4%. C16H18O2 requires C, 79.3%; H, 7.5%. IR (film) ν/cmϪ1
706 s, 1089 s, 1182 m, 1448 m, 1717 s, 2844 m, 2910 m, 2931 m,
1
brm. H NMR (400 MHz, CDCl3) δ 5.83 (dddd, 1H, J = 17.3,
10.3, 7.0, 6.2, HC᎐CH ), 5.74–5.69 (2H, H4, H5), 5.25 (dd, 1H,
᎐
2
1
3038 w. H NMR (400 MHz, CDCl3) δ 7.46–7.41 (2H, Ph),
J = 17.3, 1.5, H C᎐CH), 4.95 (dd, 1H, J = 10.3, 1.5, H C᎐CH),
᎐ ᎐
2 2
7.38–7.32 (2H, Ph), 7.30–7.25 (1H, Ph), 5.88 (dm, 1H, J = 10.0,
4.16 (dm, 1H, J = 16.8, H6), 3.99 (m, 1H, H6), 3.43 (ddd, 1H,
J = 7.8, 4.5, 2.8, HC–OH), 2.48 (d, 1H, J = 2.8, HO–), 2.35
(m, 1H, H2C–), 2.13 (dm, 1H, J = 14.8, H2C–), 2.13 (dm, 1H,
J = 14.8, H2C–), 1.77 (dm, 1H, J = 18.1, H2C–), 1.48–1.41 (2H,
H2C–), 1.11 (s, 3H, H3C–). 13C NMR (100 MHz, CDCl3) δ
138.6 (1), 125.0 (1), 122.6 (1), 114.8 (2), 76.7 (1), 74.3 (0), 60.5
(2), 31.9 (2), 30.8 (2), 29.9 (2), 15.6 (3). MS (EI) m/z (%) 183
(Mϩ ϩ 1, <5), 165 (22), 147 (12), 129 (19), 105 (10), 97 (100), 81
(25), 67 (20), 55 (23).
H4/H5), 5.67 (ddm, 1H, J = 17.1, 10.5, HC᎐CH ), 5.66 (dm,
᎐
2
1H, J = 10.0, H4/H5), 4.90 (dm, 1, J = 17.1, H C᎐CH), 4.86
᎐
2
(dm, 1H, J = 10.5, H C᎐CH), 4.30–4.27 (2H, H6), 2.94 (dm,
᎐
2
1H, J = 17.3, H C–CH –C᎐O), 2.48 (dm, 1H, J = 17.3, H C–
᎐
2
2
2
CH –C᎐O), 2.62 (ddd, 1H, J = 17.8, 6.3, 1.5, H3), 2.58 (ddd,
᎐
2
1H, J = 17.8, 2.8, 1.5, H3), 2.23 (dm, 1H, J = 15.3, H C–C᎐O),
᎐
2
2.15 (dm, 1H, J = 15.3, H C–C᎐O). 13C NMR (100 MHz,
᎐
2
CDCl3) δ 209.2 (0), 139.6 (0), 137.0 (1), 128.5 (1), 127.7 (1),
125.3 (1), 125.0 (1), 122.7 (1), 114.9 (2), 83.0 (0), 62.9 (2), 35.1
(2), 30.2 (2), 27.7 (2). MS (EI) m/z (%) 243 (Mϩ ϩ 1, <5), 225
(40), 207 (10), 183 (25), 159 (60), 105 (100), 77 (20), 55 (20).
rac-(2-Phenyl-3,6-dihydro-2H-pyran-2-yl)methanol
(16a).
Obtained from 10a (0.40 g, 1.8 mmol) as a colourless solid (0.30
g, 86%), mp 110 ЊC. Found: C, 75.7%; H, 7.4%. C12H14O2
requires C, 75.8%; H, 7.4%. IR (KBr disk) ν/cmϪ1 670 s, 697 s,
759 m, 1016 m, 1057 s, 1090 s, 1187 m, 1447 m, 2840 m, 2907 m,
3263 brs. 1H NMR (400 MHz, CDCl3) δ 7.48–7.27 (5H, Ph), 5.91
(dm, 1H, J = 10.0, H4/H5), 5.58 (dm, 1H, J = 10.0, H4/H5),
4.20 (dm, 1H, J = 16.8, H6), 4.02 (dm, 1H, J = 16.8, H6), 3.71
(dd, 1H, J = 11.3, 4.3, H2C–OH), 3.55 (dd, 1H, J = 11.3, 9.3,
H2C–OH), 2.82 (dm, 1H, J = 17.8, H3), 2.63 (dm, 1H, J = 17.8,
H3), 2.12 (dd, 1H, J = 9.0, 4.3, HO–). 13C NMR (100 MHz,
CDCl3) δ 140.4 (0), 128.4 (1), 127.6 (1), 126.7(1), 125.4 (1),
rac-1-(2-Methyl-3,6-dihydro-2H-pyran-2-yl)pent-4-en-1-one
(14b). Ring closing metathesis of 5b (0.124 g, 0.6 mmol) in the
presence of complex B (0.035 g, 6 mol%) in refluxing toluene
(10 mL) stopped at 50% conversion. 5b and 14b were obtained
as an inseparable mixture. NMR-data obtained from the mix-
1
ture: H NMR (400 MHz, CDCl3) δ 5.74 (ddm, 1H, J = 17.1,
10.3, HC᎐CH ), 5.73 (dm, 1H, J = 10.3, H4/H5), 5.63 (dm, 1H,
᎐
2
J = 10.3, H4/H5), 4.99 (dm, 1H, J = 17.1, H C᎐CH), 4.91
᎐
2
(dm, 1H, J = 10.3, H C᎐CH), 4.19 (s, 2H, H6), 2.70 (dm,
᎐
2
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
2923

View Online
122.9 (1), 76.7 (0), 70.4 (2), 61.7 (2), 27.5 (2). MS (EI) m/z (%)
173 (Mϩ Ϫ 17, 38), 159 (80), 155 (50), 105 (100), 91 (42), 77
(25).
eomers) Yield: 0.14 g (17%) of a 2:1 mixture of diastereomers.
IR (film) ν/cmϪ1 924 m, 997 m, 1091 s, 1374 m, 2836 m, 2974 m,
3457 brm. 1H NMR (400 MHz, CDCl3) δ 5.80 (dddd, 1H,
J = 17.0, 10.5, 6.3, 6.3, HC᎐CH ), 5.73–5.60 (2H, H4, H5), 5.29
(dddd, 1H, J = 17.0, 1.5, 1.5, 1.5, H C᎐CH), 5.16 (dddd, 1H,
᎐
2
᎐
2
rac-(2-Methyl-3,6-dihydro-2H-pyran-2-yl)methanol
(16b).
Obtained from 10b (0.50 g, 3.2 mmol) as a colourless liquid
(0.38 g, 93%). IR (film) ν/cmϪ1 652 s, 827 m, 1054 s, 1089 s, 1190
m, 1388 m, 1715 m, 2894 m, 2933 s, 2975 m, 3424 brs. 1H NMR
(400 MHz, CDCl3) δ 5.74 (ddddd, 1H, J = 10.3, 2.5, 2.5, 2.5,
2.5, H4/H5), 5.66 (ddddd, 1H, J = 10.3, 2.5, 2.5, 2.5, 2.5, H4/
H5), 4.15 (dm, 1H, J = 16.8, H6), 4.10 (dm, 1H, J = 16.8, H6),
3.46 (d, 1H, J = 11.3, H2C–OH), 3.39 (d, 1H, J = 11.3, H2C–
OH), 2.27 (ddddd, 1H, J = 17.5, 2.5, 2.5, 2.5, 2.5, H3), 2.26 (brs,
1H, HO–), 1.72 (ddddd, 1H, J = 17.5, 2.5, 2.5, 2.5, 2.5, H3),
1.15 (s, 3H, H3C–). 13C NMR (100 MHz, CDCl3) δ 124.8 (1),
122.8 (1), 72.0 (0), 69.1 (2), 60.9 (2), 30.6 (2), 19.6 (3). MS (EI)
m/z (%) 129 (Mϩ ϩ 1, <5), 111 (30), 97 (100), 93 (60), 81 (50), 75
(36), 67 (39), 53 (42).
J = 10.5, 1.5, 1.5, 1.5, H C᎐CH), 4.14–4.08 (2H, H6), 3.94 (dm,
᎐
2
1H, J = 5.5, HC–OH), 2.73 (d, 1H, J = 2.3, HO–), 2.18 (dm,
1H, J = 17.3, H2C–C), 1.71 (dm, 1H, J = 17.3, H2C–C), 1.08
(s, 3H, H3C–). 13C NMR (100 MHz, CDCl3) δ 135.4 (1), 124.9
(1), 122.4 (1), 117.4 (2), 77.9 (1), 73.9 (0), 60.6 (2), 31.4 (2), 16.6
(3). MS (EI) m/z (%) 153 (Mϩ Ϫ 1, <5), 137 (45), 119 (15), 109
(20), 97 (100), 93 (25), 79 (10), 55 (40). NMR data of the minor
diastereomer (obtained from the mixture): 1H NMR (400 MHz,
CDCl ) δ 5.32 (dddd, 1H, J = 17.3, 1.5, 1.5, 1.5, H C᎐CH), 5.18
᎐
2
3
(dddd, 1H, J = 10.5, 1.5, 1.5, 1.5, H C᎐CH), 2.87 (brs, 1H,
᎐
2
HO–), 2.43 (dm, 1H, J = 17.3, H2C–C), 1.54 (dm, 1H, J = 17.3,
H2C–C), 1.11 (s, 3H, H3C–). 13C NMR (100 MHz, CDCl3)
δ 135.3 (1), 124.4 (1), 123.0 (1), 117.8 (2), 78.5 (1), 73.6 (0),
60.9 (2), 28.2 (2), 18.5 (3).
(2-Allyl-3,6-dihydro-2H-pyran-2-yl)methanol (16c). Obtained
from 10c (0.85 g, 4.7 mmol) as a colourless liquid (0.48 g, 66%).
Found: C, 69.1%; H, 8.9%. C9H14O2 requires C, 70.1%; H,
9.1%. IR (KBr disk) ν/cmϪ1 656 m, 916 s, 1091 s, 1432 m, 1639
(R*)-2-((S*)-2-Phenyl-3,6-dihydro-2H-pyran-2-yl)-2,3,4,7-
tetrahydrooxepine (21a). Obtained from 7a (0.60 g, 1.9 mmol)
and catalyst A (0.10 g, 6 mol%) as a colourless liquid. Purifica-
tion by chromatography on silica (cyclohexane–MTBE = 5:1).
Yield: 0.20 g (41%). Found: C, 79.7%; H, 7.8%. C17H20O2
requires C, 79.7%; H, 7.9%. IR (film) ν/cmϪ1 656 m, 701 s, 1014
s, 1137 s, 1448 m, 2831 m, 2927 m, 3033 w. 1H NMR (400 MHz,
CDCl3) δ 7.47–7.41 (2H, Ph), 7.36–7.30 (2H, Ph), 7.29–7.24
(1H, Ph), 5.88 (ddd, 1H, J = 10.0, 5.3, 2.5, H4), 5.71 (dm, 1H,
J = 10.0, HC–CH2–CH2), 5.60 (dm, 1H, J = 10.0, HC–CH2–O–
CH), 5.53 (dm, 1H, J = 10.0, H5), 4.44 (dd, 1H, J = 16.1, 4.5,
H2C–O–CH), 4.17 (dm, 1H, J = 16.8, H6), 4.10 (ddd, 1H,
J = 16.1, 2.3, 2.3, H2C–O–CH), 3.89 (dm, 1H, J = 16.8, H6),
3.69 (dd, 1H, J = 9.3, 2.8, HC–O), 2.85 (ddddd, 1H, J = 17.6,
2.8, 2.8, 2.8, 2.8, H3), 2.65 (dm, 1H, J = 17.6, H3), 2.24 (dddm,
1H, J = 16.6, 5.8, 4.3, H2C–CH2–CH), 1.90 (ddm, 1H, J = 16.6,
6.7, H2C–CH2–CH), 1.62 (ddddm, 1H, J = 14.0, 6.7, 4.3, 2.8,
H2C–CH–C), 1.36 (ddddd, 1H, J = 14.0, 9.5, 9.3, 4.3, 1.5, H2C–
CH–C). 13C NMR (100 MHz, CDCl3) δ 140.2 (0, Ph), 130.6
((1), CH–CH2–CH2), 129.4 ((1), CH–CH2–O–CH), 127.8,
127.4, 127.1 ((1), Ph), 125.7 ((1), C5), 122.9 ((1), C4), 86.9 ((1),
CH–O), 78.5 ((0), C2), 69.8 ((2), CH2–O–CH), 61.8 ((2), C6),
28.8 ((2), CH2–CH–C), 26.7 ((2), C3), 26.4 ((2), CH2–CH2–
CH). MS (EI) m/z (%) 257 (Mϩ ϩ 1, 15), 239 (58), 221 (25), 185
(10), 159 (100), 143 (12), 105 (75), 77 (12), 67 (12).
1
w, 2836 s, 2927 s, 3446 s. H NMR (400 MHz, CDCl3) δ 5.73
(dddd, 1H, J = 17.3, 10.3, 7.8, 7.0, –CH᎐CH ), 5.69 (dm, 1H,
᎐
2
J = 10.3, H4/H5), 5.63 (dm, 1H, J = 10.3, H4/H5), 5.02
(dm, 1H, J = 17.3, ᎐CH ), 5.01 (dm, 1H, J = 10.3, ᎐CH ), 4.12
᎐
᎐
2
2
(dm, 1H, J = 17.0, H6), 4.06 (dm, 1H, J = 17.0, H6), 3.46–3.39
(2H, H2C–OH), 2.58 br (s, 1H, H2C–OH), 2.36 (dd, 1H,
J = 14.1, 7.0, –CHHCH᎐CH ), 2.23 (dd, 1H, J = 14.1, 7.8,
᎐
2
–CHHCH᎐CH ), 2.05 (dm, 1H, J = 17.6, H3), 1.84 (dm, 1H,
᎐
2
J = 17.6, H3). 13C NMR (100 MHz, CDCl3) δ 133.3 (1), 124.7
(1), 122.4 (1), 118.0 (2), 73.7 (0), 65.8 (2), 60.7 (2), 37.6 (2), 28.3
(2). MS (EI) m/z (%) 153 (Mϩ Ϫ 1, 2%), 137 (Mϩ Ϫ OH, 20),
113 (Mϩ Ϫ allyl, 100).
rac-2-Phenyl-3,6-dihydro-2H-pyran-2-carbaldehyde
(17a).
Obtained from 11a (0.15 g, 0.7 mmol) and the Grubbs’ catalyst
A (8 mol%) in refluxing toluene. Yield: 0.090 g (69%). IR (film):
ν/cmϪ1 660 m, 699 s, 1087 s, 1449 m, 1735 s, 2844 w, 2931 m,
1
3053 w. H NMR (400 MHz, CDCl3) δ 9.50 (s, 1H, –CHO),
7.43-7.28 (5H, Ph), 5.86 (ddddd, 1H, J = 10.3, 2.3, 2.3, 2.3, 2.3,
H4/H5), 5.67 (dddd, 1H, J = 10.3, 2.3, 2.3, 2.3, H4/H5), 4.44
(ddddd, 1H, J = 17.3, 2.3, 2.3, 2.3, 2.3, H6), 4.33 (ddddd, 1H,
J = 17.3, 2.3, 2.3, 2.3, 2.3, H6), 2.88 (ddddd, 1H, 17.5, 2.3, 2.3,
2.3, 2.3, H3), 2.45 (ddddd, 1H, 17.5, 2.3, 2.3, 2.3, 2.3, H3). 13
C
NMR (100 MHz, CDCl3) δ 199.3 (1), 137.1 (0), 128.8 (1), 128.3
(1), 126.0 (1), 125.5 (1), 122.3 (1), 81.5 (0), 63.1 (2), 28.7 (2). MS
(EI) m/z (%) 189 (Mϩ ϩ 1, 20), 183 (20), 171 (100), 159 (75), 105
(98), 77 (45), 51 (20).
2-(2-Methyl-3,6-dihydro-2H-pyran-2-yl)-2,3,4,7-tetra-
hydrooxepine (21b). Obtained from 7b (0.20 g, 0.80 mmol,
2:1 mixture of diastereomers) and catalyst B (8 mol%) in
refluxing toluene as a colourless liquid. After chromatography a
single diastereomer of 18b (0.10 g, 64%) was obtained. IR (film)
ν/cmϪ1 799 m, 1018 s, 1092 s, 1261 m, 2934 m, 2963 m. 1H NMR
(400 MHz, CDCl3) δ 5.81–5.64 (3H, H4/5 ϩ HC–CH2–CH2),
5.58 (dm, 1H, J = 11.3, H4/5), 4.46 (dd, 1H, J = 16.2, 4.5, H2C–
O–CH), 4.20–4.08 (2H, H6), 4.02 (dm, 1H, J = 16.2, H2C–O–
CH), 3.31 (dd, 1H, J = 9.3, 3.3, HC–O), 2.47 (m, 1H, CHH),
2.30 (m, 1H, CHH), 2.05 (m, 1H, CHH), 1.92 (m, 1H, CHH),
(2R*,3S*)-2-Allyl-2-phenyl-3,6-dihydro-2H-pyran-3-ol (18a).
Obtained from (3S*, 4R*)-8a (0.56 g, 2.3 mmol) as a colourless
liquid. Yield: 0.20 g (40%). IR (film) ν/cmϪ1 701 s, 919 m, 1025 s,
1092 s, 1182 m, 1272 m, 1448 m, 1757 m, 2841 w, 2932 w, 3035
1
w, 3443 brm. H NMR (400 MHz, CDCl3) δ 7.53–7.25 (5H,
Ph), 6.12 (dddd, 1H, J = 10.0, 5.3, 2.5, 2.5, H4), 6.01 (ddd, 1H,
J = 10.0, 2.5, 2.5, H5), 5.50 (dddd, 1H, J = 17.3, 10.0, 7.5, 6.3,
1.71 (m, 1H, CHH), 1.69 (m, 1H, CHH), 1.19 (s, 3H, CH3). 13
C
HC᎐CH ), 5.03 (dddd, 1H, J = 17.1, 1.5, 1.5, 1.5, H C᎐CH),
NMR (100 MHz, CDCl3) δ 130.5 (1), 129.5 (1), 125.2 (1), 122.9
(1), 86.5 (1), 74.1 (0), 70.3 (2), 61.0 (2), 30.6 (2), 28.5 (2), 26.3
(2), 18.4 (3). MS (EI) m/z (%) 195 (Mϩ ϩ 1, 12), 177 (52), 165
(45), 159 (20), 147 (20), 141 (20), 107 (25), 97 (100), 81 (25), 53
(20).
᎐
᎐
2
2
4.96 (dddd, 1H, J = 10.0, 1.5, 1.5, 1.5, H C᎐CH), 4.38–4.36
᎐
2
(2H, H6), 4.12 (d, 1H, J = 5.3, H3), 2.86 (dddd, 1H, J = 14.8,
7.5, 1.5, 1.5, H2C–C), 2.49 (dddd, 1H, J = 14.8, 6.3, 1.5, 1.5,
H2C–), 1.67 (brs, 1H, HO–). 13C NMR (100 MHz, CDCl3)
δ 141.6 (0), 133.5 (1), 129.3 (1), 128.1 (1), 127.1 (1), 125.8 (1),
125.2 (1), 117.6 (2), 79.7 (0), 67.3 (1), 61.3 (2), 39.4 (2). MS (EI)
m/z (%) 215 (Mϩ Ϫ 1, <5), 199 (72), 181 (15), 157 (100), 131
(16), 95 (18).
(2S*)-2-((R*)-2,3–Dihydrofuran-2-yl)-2-phenyl-3,6-dihydro-
2H-pyran (22a). Obtained from (1S*,2R*)-9a (0.60 g, 2.1
mmol). Yield: 0.15 g (45%). IR (film) ν/cmϪ1 656 m, 701 s, 728
m, 1057 m, 1086 s, 1179 m, 1448 m, 2848 s, 2924 m, 3035 m. 1H
NMR (400 MHz, CDCl3) δ 7.34 (d, 2H, J = 8.0, o-H, Ph), 7.27
(dd, 2H, J = 8.0, 7.0, m-H, Ph), 7.21 (t, 1H, J = 7.0, p-H, Ph),
1-(2-Methyl-3,6-dihydro-2H-pyran-2-yl)prop-2-en-1-ol (19b).
Obtained from 8b (0.80 g, 3.3 mmol; 2:1 mixture of diaster-
2924
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925

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7 M. H. D. Postema, C-Glycoside Synthesis, CRC Press, Boca Raton,
FL, 1995.
5.79 (dm, 1H, J = 10.3, H4), 5.77 (dm, 1H, J = 6.0, HC–CH–C),
5.44 (dm, 1H, J = 10.3, H5), 5.26 (dm, 1H, J = 6.0, HC᎐CH–
᎐
8 D. E. Levy and C. Tang, The Chemistry of C-Glycosides, ed. J. E.
Baldwin and P. D. Magnus, Pergamon, Oxford, 1995.
9 Y. Du, R. J. Linhardt and I. R. Vlahov, Tetrahedron, 1998, 54, 9913.
10 M. C. Elliott, J. Chem. Soc., Perkin Trans. 1, 1998, 4175.
11 M. C. Elliott, J. Chem. Soc., Perkin Trans. 1, 2000, 1291.
12 B. Schmidt and T. Sattelkau, Tetrahedron, 1997, 53, 12991.
13 B. Schmidt, Org. Lett., 2000, 2, 791.
14 M. E. Maier and M. Bugl, Synlett, 1998, 1390.
15 B. Schmidt, J. Chem. Soc., Perkin Trans. 1, 1999, 2627.
16 K. C. Nicolaou, R. M. Rodríguez, H. J. Mitchell and F. L. van Delft,
Angew. Chem., 1998, 110, 1975; K. C. Nicolaou, R. M. Rodríguez,
H. J. Mitchell and F. L. van Delft, Angew. Chem. Int., 1998, 37, 1874.
17 F. P. J. T. Rutjes, M. Kooistra, H. Hiemstra and H. E. Schoemaker,
Synlett, 1998, 192.
18 S. D. Burke, R. A. Ng, J. A. Morrison and M. J. Alberti, J. Org.
Chem., 1998, 63, 3160.
19 J. F. Miller, A. Termin, K. Koch and A. D. Piscopio, J. Org. Chem.,
1998, 63, 3158.
20 M. T. Crimmins and A. L. Choy, J. Org. Chem., 1997, 62, 7548.
21 M. T. Crimmins and A. L. Choy, J. Am. Chem. Soc., 1999, 121,
5653.
22 H. Ovaa, M. A. Leeuwenburgh, H. S. Overkleeft, G. A. van der
Marel and J. H. van Boom, Tetrahedron Lett., 1998, 39, 3025.
23 P. A. V. van Hooft, M. A. Leeuwenburgh, H. S. Overkleeft, G. A.
van der Marel, C. A. A. van Boeckel and J. H. van Boom,
Tetrahedron Lett., 1998, 39, 6061.
24 D. J. Holt, W. D. Barker, P. R. Jenkins, D. L. Davies, S. Garratt,
J. Fawcett, D. R. Russell and S. Ghosh, Angew. Chem., 1998,
110, 3486; D. J. Holt, W. D. Barker, P. R. Jenkins, D. L. Davies,
S. Garratt, J. Fawcett, D. R. Russell and S. Ghosh, Angew. Chem.,
Int. Ed., 1998, 37, 3298.
25 D. J. Holt, W. D. Barker, P. R. Jenkins, J. Panda and S. Ghosh,
J. Org. Chem., 2000, 65, 482.
26 M. A. Leeuwenburgh, H. S. Overkleeft, G. A. van der Marel and
J. H. van Boom, Synlett, 1997, 1263.
27 M. A. Leeuwenburgh, C. Kulker, H. I. Duynstee, H. S. Overkleeft,
G. A. van der Marel and J. H. van Boom, Tetrahedron, 1999, 55,
8253.
CH), 4.94 (m, 1H, HC–O), 4.57 (dm, 1H, J = 13.1, H2C–O–
CH), 4.47 (dddm, 1H, J = 13.1, 6.5, 2.0, H2C–O–CH), 4.12 (dm,
1H, J = 16.8, H6), 3.82 (dm, 1H, J = 16.8, H6), 2.59 (dm, 1H,
J = 17.8, H3), 2.48 (dm, 1H, J = 17.8, H3). 13C NMR (100
MHz, CDCl3) δ 139.4 ((0), Ph), 128.5 ((1), CH–CH–C), 128.0
((1), Ph), 127.4 ((1), Ph), 127.4 ((1), Ph), 125.9 ((1), CH᎐CH–
᎐
CH), 125.8 ((1), C5), 122.6 ((1), C4), 92.8 ((1), CH–O), 79.0
((0), C2), 76.6 ((2), CH2–O–CH), 61.8 ((2), C6), 25.5 ((2), C3).
MS (EI) m/z (%) 227 (Mϩ Ϫ 1, <5), 211 (50), 193 (20), 159
(100), 105 (80), 77 (15), 69 (20).
(2R*)- and (2S*)-2-((R*)-2,3-Dihydrofuran-2-yl)-2-methyl-
3,6-dihydro-2H-pyran (22b). Obtained from 9b (0.17 g, 0.8
mmol 2:1 mixture of diastereomers) and catalyst B (7.5 mol%)
in refluxing toluene as a mixture of two diastereomers
(dr = 2:1). Yield: 0.06 g (47%). IR (film) ν/cmϪ1 654 m, 827 m,
1
920 m, 1094 s, 1133 m, 1759 s, 2844 m, 2934 m, 2978 m. H
NMR (400 MHz, CDCl3) δ 5.97 (dm, 1H, J = 6.3, –OCH-
HCH᎐CH–), 5.73 (dm, 1H, J = 6.3, –OCHHCH᎐CH–), 5.69
᎐
᎐
(m, 1H, H4), 5.66 (dm, 1H, J = 10.3, H5), 4.71 (m, 1H, HC–O),
4.63–4.60 (2H, H2C–O), 4.14–4.10 (2H, H6), 2.13 (ddm,
1H, J = 17.3, 2.3, H3), 1.70 (ddm, 1H, J = 17.3, 2.3, H3), 1.13
(s, 3H, H3C). 13C NMR (100 MHz, CDCl3) δ 128.6 (1),
126.2 (1), 125.4 (1), 122,4 (1), 91.6 (1), 75.9 (2), 74.3 (0), 60.7 (2),
30.2 (2), 17.9 (3). MS (EI) m/z (%) 167 (Mϩ ϩ 1, <5), 149
(30), 131 (34), 113 (70), 97 (100), 69 (50). NMR data of the
minor diastereomer (obtained from the mixture): 1H NMR
(400 MHz, CDCl ) δ 5.80 (dm, 1H, J = 6.3, HC᎐CH), 2.24 (dm,
᎐
3
1H, J = 17.3, H3), 1.81 (dm, 1H, J = 17.3, H3), 1.05 (s, 3H,
H3C). 13C NMR (100 MHz, CDCl3) δ 128.1 (1), 126.5 (1), 125.0
(1), 122.8 (1), 91.2 (1), 75.9 (2), 73.9 (0), 61.0 (2), 31.4 (2), 17.9
(3).
28 B. Schmidt and M. Westhus, Tetrahedron, 2000, 56, 2421.
29 J. S. Clark and J. G. Kettle, Tetrahedron Lett., 1997, 38, 127.
30 S. D. Edwards, T. Lewis and R. J. K. Taylor, Tetrahedron Lett., 1999,
40, 4267.
31 B. Schmidt and H. Wildemann, Synlett, 1999, 1591.
32 G. M. Coppola and H. F. Schuster, α-Hydroxy acids in
enantioselective synthesis, Wiley-VCH, Weinheim, 1997.
33 K. Matsuo, T. Arase, S. Ishida and Y. Sakaguchi, Heterocycles,
1996, 43, 1287.
34 R. P. Hof and R. M. Kellogg, J. Chem. Soc., Perkin Trans. 1, 1996,
2051.
35 R. A. Aitken and A. W. Thomas, Synlett, 1997, 293.
36 D. J. Cram and D. R. Wilson, J. Am. Chem. Soc., 1963, 85, 1245.
37 N. T. Anh, Top. Curr. Chem., 1980, 88, 145.
1,8-Dioxaspiro[5.6]dodeca-3,10-diene (23c). Obtained from
12c (0.56 g, 2.5 mmol). Yield: 0.21 g (50%). IR (film) ν/cmϪ1 655
s, 1093 s, 1123, s, 1459 s, 1656 m, 2827 s, 2931 s, 3032 s. 1H NMR
(400 MHz, CDCl ) δ 5.72–5.55 (4H, H4/5, HC᎐CH), 4.26 (dm,
᎐
3
1H, J = 16.3, OCHHCH᎐), 4.16 (dm, 1H, J = 16.3, OCH-
᎐
HCH᎐), 4.08 (dm, 1H, J = 17.3, OCHHCH᎐), 4.02 (dm, 1H,
᎐
᎐
J = 17.3, OCHHCH᎐), 3.70 (d, 1H, J = 12.8, OCHHC), 3.57 (d,
᎐
1H, J = 12.8, OCHHC), 2.47 (dm, 1H, J = 13.8, CCHH), 2.41
(dm, 1H, J = 13.8, CCHH), 1.97 (dm, 1H, J = 13.8, H3), 1.85
(dm, 1H, J = 13.8, H3). 13C NMR (100 MHz, CDCl3) δ 130.1
(1), 125.6 (1), 125.3 (1), 122.4 (1), 78.6 (2), 75.5 (0), 70.8 (2), 61.3
(2), 33.1 (2), 31.4 (2). MS (EI) m/z (%) 167 (Mϩ ϩ 1, 30), 134
(85), 113 (100).
38 A. Fürstner and K. Langemann, Synthesis, 1997, 792.
39 A. Fürstner, A. F. Hill, M. Liebl and J. D. E. T. Wilton-Ely, Chem.
Commun., 1999, 601.
40 K. J. Harlow, A. F. Hill and J. D. E. T. Wilton-Ely, J. Chem. Soc.,
Dalton Trans., 1999, 285.
41 C. Bruneau and P. H. Dixneuf, Acc. Chem. Res., 1999, 32, 311.
42 A. Fürstner, O. R. Thiel, L. Ackermann, H.-J. Schanz and S. P.
Nolan, J. Org. Chem., 2000, 65, 2204.
43 M. T. Reetz, M. H. Becker, M. Liebl and A. Fürstner, Angew.
Chem., 2000, 112, 1294; M. T. Reetz, M. H. Becker, M. Liebl and
A. Fürstner, Angew. Chem. Int., 2000, 39, 1236.
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft and the
Fonds der Chemischen Industrie for generous financial support.
Technical assistance by Ms S. Vogt is gratefully acknowledged.
B. S. thanks Professor Dr P. Eilbracht for his support and
interest in this project.
44 C. Baylon, M.-P. Heck and C. Mioskowski, J. Org. Chem., 1999, 64,
3354.
45 W. J. Zuercher, M. Hashimoto and R. H. Grubbs, J. Am. Chem.
Soc., 1996, 118, 6634.
46 R. Stragies and S. Blechert, Synlett, 1998, 169.
47 R. Stragies and S. Blechert, Tetrahedron, 1999, 55, 8179.
48 J. A. Adams, J. G. Ford, P. J. Stamatos and A. H. Hoveyda, J. Org.
Chem., 1999, 64, 9690.
References
1 S. T. Nguyen, L. K. Johnson and R. H. Grubbs, J. Am. Chem. Soc.,
1992, 114, 3974.
2 G. C. Fu, S. T. Nguyen, R. H. Grubbs and J. W. Ziller, J. Am. Chem.
Soc., 1993, 115, 9856.
3 P. Schwab, R. H. Grubbs and J. W. Ziller, J. Am. Chem. Soc., 1996,
118, 100.
4 S. K. Armstrong, J. Chem. Soc., Perkin Trans. 1, 1998, 371.
5 R. H. Grubbs and S. Chang, Tetrahedron, 1998, 54, 4413.
6 A. Fürstner, Synlett, 1999, 1523.
49 D. S. La, J. G. Ford, E. S. Sattely, P. J. Bonitatebus, R. R. Schrock
and A. H. Hoveyda, J. Am. Chem. Soc., 1999, 121, 11603.
50 G. S. Weatherfield, J. G. Ford, E. J. Alexanian, R. R. Schrock and
A. H. Hoveyda, J. Am. Chem. Soc., 2000, 122, 1828.
51 M. J. Bassindale, P. Hamley, A. Leitner and J. P. A. Harrity,
Tetrahedron Lett., 1999, 40, 3247.
52 S. Hosokawa and M. Isobe, J. Org. Chem., 1999, 64, 37.
J. Chem. Soc., Perkin Trans. 1, 2000, 2916–2925
2925