Nazarov cyclization of 4-cycloalkylidene-5-(trimethylsilyl)pent-1-en-3-one derivatives. Synthesis of spiro[4.5]decane, Spiro[4.4]nonane, and Their derivatives

Article abstract of DOI:10.1016/S0040-4020(00)00589-5

Spiro[4.5]decane and spiro[4.4]nonane ring systems were synthesized by FeCl₃-induced Nazarov cyclization of α-(trimethylsilylmethyl)divinyl ketone derivatives. It was found that the double bond position of the product is controlled by the presence/absence of α'-substituent, while trimethylsilyl group is essential to obtain the products in good yields. Spiro[4.4]nonanes having exo-methylene group underwent rearrangement to bicyclo[4.3.0]nonanes. (C) 2000 Elsevier Science Ltd.

Full text of DOI:10.1016/S0040-4020(00)00589-5

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 6441±6455
Nazarov Cyclization of
4-Cycloalkylidene-5-(trimethylsilyl)pent-1-en-3-one Derivatives.
Synthesis of Spiro[4.5]decane, Spiro[4.4]nonane,
and Their Derivatives
*
Chiaki Kuroda, Hiroyuki Koshio, Akira Koito, Hiroshi Sumiya, Atsushi Murase and
Yukari Hirono
Department of Chemistry, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
Received 26 April 2000; accepted 27 June 2000
AbstractÐSpiro[4.5]decane and spiro[4.4]nonane ring systems were synthesized by FeCl3-induced Nazarov cyclization of a-(trimethyl-
silylmethyl)divinyl ketone derivatives. It was found that the double bond position of the product is controlled by the presence/absence of
a0-substituent, while trimethylsilyl group is essential to obtain the products in good yields. Spiro[4.4]nonanes having exo-methylene group
underwent rearrangement to bicyclo[4.3.0]nonanes. q 2000 Elsevier Science Ltd. All rights reserved.
Introduction
conjugated b-carbonylallylsilane is a-(trimethylsilyl-
methyl)divinyl ketone, which can easily be obtained from
b-(ethoxycarbonyl)allylsilane.
The
a-(trimethylsilyl-
Allylsilanes are versatile building blocks and the allylanion
equivalent in organic synthesis,1 while conjugated carbonyl
groups are typical Michael acceptors. Therefore, conjugated
allylsilane with a carbonyl group at the b-position
(b-carbonylallylsilane), or its equivalent, is a unique
block, since this moiety can react formally as both a nucleo-
phile (allylsilane) and an electrophile (conjugated carbonyl)
at the same carbon. This makes it easy to synthesize odd
membered cyclic compounds.2 We synthesized ®ve-
membered lactones3,4 or carbocycles5 related to sesquiter-
penoids using intramolecular cyclization of b-(ethoxy-
carbonyl)allylsilane with carbonyl or conjugated carbonyl
groups, respectively, as shown in the general Scheme 1.6
The synthesis of ®ve- and seven-membered rings was also
developed from related b-(functionalizedmethyl)allyl-
silanes, such as b-(dialkoxymethyl)-,7 b-(halomethyl)-,8
and b-(hydroxymethyl)allylsilanes9 including a silylated
derivative10 and Trost's trimethylenemethane.11
methyl)divinyl ketone moiety must be a good precursor
for the Nazarov cyclization reaction, which would formally
proceed as illustrated in Scheme 2, and thus the reaction is
expected to proceed easily.
Nazarov cyclization is one of the classical methods to
synthesize ®ve-membered carbocycles.14 Denmark et al.
developed silicon-directed Nazarov cyclization reaction
utilizing both vinyl-15 and allyl-silane16 derivatives, the
latter of which represents remarkable rate enhancement.
Moreover, although studies were made on limited ring
Compounds having further conjugated CvC double bond to
the b-carbonylallylsilane moiety are not a simple variation,
since extension of conjugated double bond itself enables
®ve-membered ring formation. We reported that 2-(tri-
methylsilylmethyl)pentadienoic acid cyclizes itself to
yield ®ve-membered lactone.12,13 Another type of further
Keywords: Nazarov reactions; rearrangements; silicon and compounds;
spiro compounds.
* Corresponding author. Tel.: 181-3-3985-2396; fax: 181-3-5992-3434;
e-mail: kuroda@rikkyo.ac.jp
Scheme 1.
0040±4020/00/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00589-5

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C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
Results and Discussion
Initial study: synthesis of spiro[4.5]decanes18
We ®rst studied the cyclization of 1±3 into spiro[4.5]-
decanes. The Nazarov cyclization of 1 was carried out
using FeCl3 as a Lewis acid according to Kang's pro-
cedure17 with a slight modi®cation. Namely, 2.5 equiv. of
FeCl3 was added to a solution of 1 in CH2Cl2 at 2608C, and
then the reaction mixture was slowly warmed to room
temperature over a period of 7 h, giving a diastereomeric
mixture of the spiro compounds, 4a and 4b, in 59% yield
(Scheme 3). These two isomers could not be isolated from
each other, and the ratio was determined to be 4a:4bˆ5:1
Scheme 2.
1
from the H NMR spectrum. The stereochemistry of the
product was established from an NOE measurement, in
which NOE was observed between the t-butyl group and
one of the exo-methylenic protons for 4b. The reaction at
2608C proceeded very slowly, while the reaction proceeded
almost at once when FeCl3 was added at 08C, giving the
products in lower yield (34%) together with many
by-products as detected on TLC.
Compound 2 produced a mixture of 5a and 5b (61%,
ratio 5:1) under the same reaction conditions (2.5 equiv.
of FeCl3, CH2Cl2, 2608C to room temperature). Similarly,
3 gave 6 in 67% yield. The structure of 5a and 5b was
deduced from the chemical shifts of the ole®nic protons
compared with those of 4a and 4b. By TLC monitoring it
was found that the reaction of 3 completed at 2158C (after
3.5 h warming from 2608C) giving the product 6 in 67%
yield.
Scheme 3.
systems, the location of the double bond in the product is
controlled by the position of the allylic silicon atom, as
expected in Scheme 2.16a Kang et al.17 reported the synthesis
of various a-methylenecyclopentanones utilizing Nazarov
cyclization of a0- and/or b0-substituted a-(trimethylsilyl-
methyl)divinyl ketones, however the reaction of b-substi-
tuted or b,b-disubstituted compounds were not studied. We
reported the synthesis of the spiro[4.5]decane ring system,18
one of the common structures in sesquiterpenes such as
acoranes or vetispiranes,19,20 using the Nazarov cycliza-
tion of b,b-disubstituted a-(trimethylsilylmethyl)divinyl
ketones derived from b-(ethoxycarbonyl)allylsilane. We
also reported that spiro[4.4]nonanes,21 obtained by the
same methodology, undergo skeletal rearrangement
under the Nazarov condition to give bicyclo[4.3.0]no-
nanes.22 Here we describe the full details of these reactions
as well as the substituent effect on divinyl ketone moiety,
which controls the double bond direction of the Nazarov
cyclization.
Tandem Nazarov cyclizationÐskeletal rearrangement22
Nazarov cyclization of the analogous compound 7, divinyl
ketone attached to ®ve-membered ring, was studied next.
When 7 was treated with FeCl3 in CH2Cl2 at 2308C and
then slowly warmed to 08C for 4 h, the expected product
spiro[4.4]nonane 8 was afforded in 56% yield. By TLC
monitoring it was found that the reaction proceeds very
slowly below 2308C. On the other hand, when 7 was treated
at a higher temperature (i.e. when FeCl3 was added at
2108C then stirred at room temperature for 24 h) compound
923 was obtained as the sole product in 62% yield
(Scheme 4). Treatment of 8 under the same reaction con-
dition (FeCl3, room temperature, 24 h) gave 9 in 60% yield.
Scheme 4.

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6443
Table 1. Tandem Nazarov cyclization±rearrangement of 10a and 10b (all reactions were carried out with 2.5 equiv. of FeCl3 in CH2Cl2)
Entry
Substrate
Temperature
Time (h)
Yield (%)
Ratio (12a:12b:12c:12d:12e)
1
2
3
4
5
6
10a
10b
rtc
rtc
rtc
rtc
rtd
rtd
25
26
49
53
25
18
64
65
67
63
67
69
72:12:5:3:8
46:32:10:6:6
69:13:5:4:9
42:25:10:11:12
13:13:9:26:39
9:0:0:22:69
11a111b (4:1)a
11a111b (1:1)b
10b
11a111b (4:1)a
a Obtained from 10a; see text.
b Obtained from 10b; see text.
c The reagents were added at 2308C and then the mixture was slowly warmed to room temperature over a period of 7 h, which is included in the reaction
time.
d The reagents were added at 2308C and the cooling bath was immediately removed.
From these results, along with the observation of the
behavior on TLC, it was suggested that 9 was formed
from 7 via 8 as the intermediate.
spiro[4.4]nonane. Thus, both direct treatment of 10a
(entry 1) and treatment of the mixture of spiro compounds
obtained from 10a (entry 3) afforded mixtures of ®ve
isomers of 12 in similar ratios. The parallel result was
also obtained from 10b (entries 2 and 4). By comparison
of the data of entries 3 and 4, it could be deduced that 12a is
formed from 11a with about 90% selectivity, and 12b is the
major product from 11b. Mixtures of isomers 12a±e were
obtained in different ratios when the reaction temperature
was raised immediately after addition of the reagent (entries
5 and 6). The reaction mechanism of this rearrangement is
not clear yet, however, formally, the reaction can be con-
The stereochemistry of this tandem Nazarov cyclizationÐ
skeletal rearrangement was studied using methyl derivatives
10a and 10b as the substrates, which were prepared from
3-methylcyclopentanone as a 1:1 mixture and separated.
First, 10a and 10b were treated with FeCl3 at 08C (reagents
were mixed at 2308C, warmed to 08C over 2.5 h, and then
stirred at 08C for 3.5 h) giving the two isomers spiro[4.4]-
nonanes, 11a and 11b as an inseparable mixture (63% from
10a and 66% from 10b). The ratios of 11a:11b were 4:1
from 10a, and 1:1 from 10b. The stereochemistry of 11a and
11b was determined from NOE experiments (see
Experimental section).
²
sidered to proceed as shown in Scheme 5.
In order to ®nd out whether this type of skeletal rearrange-
ment also occurs from spiro[4.5]decanes, 4±6 were treated
under the same reaction conditions. However, no reaction
proceeded at all after the reaction temperature was elevated
to 708C. Accordingly, the rearrangement is considered to be
limited to the strained spiro ®ve±®ve membered ring
system.
The tandem Nazarov cyclizationÐrearrangement reaction
was carried out at room temperature. The results are
summarized in Table 1. In contrast to 9, the rearranged
product 12 consisted of ®ve isomers (12a±e) as inseparable
mixtures. The major isomer 12a was shown to have the
illustrated structure, which was determined by COSY and
NOESY spectra (see Experimental section for detail).
Although the exact structures of 12b±e could not be deter-
mined, these compounds can be classi®ed into two groups
based on J-values of the ole®nic protons, which suggests
that 12b (d 5.88 and 6.65) and 12c (d 5.84 and 6.85) have a
cis-fused hydrindane skeleton (dd, Jˆca. 2, 6 Hz, for both
ole®nic protons); 12d (d 5.81 and 6.96) and 12e (d 5.80 and
6.95) have a trans-fused hydrindane moiety (br d, Jˆ5.5 Hz,
for both ole®nic protons), by comparing their J-values with
those of 9 and 12a. It was con®rmed here again that the
bicyclo[4.3.0]nonane carbon framework is formed via
Substituent effect on divinyl ketone
The substituent effect on divinyl ketone moiety was then
examined using b0-methyl derivatives 13a,b and an
a0-methyl derivative 14 as the substrates. The geometry of
the double bond of 13a and 13b was determined from
J-values of the ole®nic protons. Both 13a and 13b afforded
the same product 15, as the case of 1±3, but the yields were
much higher, i.e. 93% from 13a and 91% from 13b (Scheme
6). It was found by monitoring on TLC that the reaction of
13b was relatively faster than 13a. Thus, the reaction of
13b ®nished below 2308C while 13a required a higher
²
Assuming Scheme 5, the structures of 12b±e can be proposed as follows
by considering stability of each compound, however, there is no experi-
mental evidence to support these structures.
Scheme 5.

6444
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
Scheme 7.
Effect of the silicon atom
The above result on the substituent effect is not consistent
with our prediction that the double-bond location in the
product is determined by silicon atom, as shown in Scheme
2. Then, to ®nd out the role of the silicon atom, compounds
24 and 25, desilylated substrate of 14 and 3, respectively,
were prepared. When 24 was treated under the same reac-
tion condition as 14, the same product 16 was obtained,
however, the yield was decreased to 32% (Scheme 7).
Compound 25 afforded 6, the same product obtained from
3, but again the yield was decreased to 39%. These results
indicate that the trimethylsilyl group does not affect the
position of the double bond in the product but is essential
in its yield. This must be the result of the stabilization of the
intermediate carbocation by silicon atom.16,24 As mentioned
above, the yields were also increased by the presence of
b0-substituent (e.g. reaction of 13a,b). This is probably
also because of the stabilization of the intermediate.
Scheme 6.
temperature. This can easily be explained by steric conges-
tion between the methyl group and the cyclohexane ring. In
contrast, 14 afforded a spiro[4.5]decane 16 having an
endocyclic double bond in 55% yield, without being
accompanied by a product having exocyclic double bond
(Scheme 6). Similarly, the ®ve-membered ring analog 17
afforded 18 in 46% yield. The reaction of 14 and 17
proceeded faster than 1 or 7. Thus after addition of FeCl3
at 2608C, the reaction was completed at 2308C (after 2 h
for warming up from 260 to 2308C). No further reaction
occurred when the ¯ask was warmed to room temperature,
while the reaction took place immediately with giving many
by-products when FeCl3 was added at 2308C. In contrast to
8 or 11a,b, no rearrangement occurred with 18 after the
reaction temperature was elevated to room temperature.
From these results, it was suggested that the position of
the double bond in the Nazarov product is determined by
the presence/absence of the a0-substituent.
After the above results, compounds 26a,b were designed
based on the assumption that (1) the product would
have endocyclic double bond because of the presence of
a0-substituent and (2) the yield would not be low without
the silicon atom because of the presence of b0-substituent.
Compounds 26a and 26b were prepared as a 3:2 mixture and
were separated by silica gel column chromatography. The
Z- and E-geometries of 26a and 26b, respectively, were
deduced by a comparison of the chemical shifts of the
ole®nic protons with those of 13a,b. When 26a and 26b
were treated with FeCl3, the expected product 27 was
afforded in 73 and 61% yields, respectively (Scheme 8).
This result con®rmed the above discussions.
Stereochemistry of the cyclization reaction
The stereoselectivity of the Nazarov cyclization can be
rationalized by simple sterical congestion. The preferential
formation of 4a and 5a over 4b and 5b, respectively, can be
rationalized by steric interaction between cyclohexane ring
and silicon-bearing carbon (not trimethylsilyl group18).
Thus as depicted in Scheme 9, the silicon-bearing carbon
To con®rm this, Nazarov cyclization of (E)-b0-phenyl
derivative 19 and a0-phenyl derivative 20 was also studied.
Compound 19 afforded exo-enone 21 in 80% yield, as the
case of 13a,b. While, 20 afforded an inseparable mixture of
endo-enone 22 and enol form of exo-enone 23 (total yield
55%; ratio 2:1). The enol structure of 23 was determined
from spectral data, including ole®nic signals in 13C NMR as
well as the absence of CHPh signal in the 1H NMR.
Although the results are not completely parallel with
methyl-substituted compounds (13a,b and 14), here again,
the position of the double bond in the product was deter-
mined by the presence/absence of the a0-substituent. The
reason why an a0-substituent determines the exo/endo
double bond in the product is not clear yet.
Scheme 8.

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6445
The preferential formation of 11a over 11b from 10a can be
explained by steric interaction between the methyl group
and the C(a0)vC(b0) double bond as shown in Scheme
10, based on the assumption that the cyclopentane ring
has envelope conformation with the biggest substituent
(divinyl ketone moiety) equatorial-like orientation. Then,
sterical congestion between methyl group and vinyl group
appears in the cyclization reaction from vii to viii, and thus
the reaction proceeded mainly through v to vi affording 11a.
The non-stereoselectivity observed for 10b can be explained
by the suf®cient distance between methyl group and the
C(a0)vC(b0) double bond in the transition state.
Synthesis of the substrates
The substrates used in this study were synthesized as
described in Scheme 11. Starting from cycloalkanones,
b-(ethoxycarbonyl)allylsilanes 28a±e were ®rst prepared
by Hoffmann's method.4,5,26 For the preparation of
desilylated substrates, enone 28f was prepared by Wittig±
Horner reaction. The resulting ethoxycarbonyl group was
then reduced by LiAlH4 to the alcohols 29a±f, which
were then converted to the aldehydes 30a±f by MnO2 oxida-
tion. To these compounds appropriate Grignard reagents
were introduced giving the alcohols 31a±m. Compounds
31a and 31b were obtained as a 1:1 mixture of the dia-
stereomers, and 31e contained four isomers, but these
mixtures were not separated from each other. Finally, the
alcohols 31a±m were oxidized by MnO2 to the substrates
used in the present study. Compounds 10a and 10b were
prepared as a mixture starting from 3-methylcyclopenta-
none and separated at the ®nal stage, after the oxidation of
31e. The double bond isomers 13a/13b and 26a/26b were
also separated at the ®nal stage.
Scheme 9.
protrudes over the cyclohexane ring in iii, which makes this
conformation unfavorable against ii. For the formation of
5b, the conformation iv (RˆMe) is also considerable since
the divinyl ketone moiety is bigger than methyl group,
however, this conformer is still less favorable than ii
because of the presence of axial methyl group. Attacking
direction to C(a)vC(b) double bond (exocyclic double
bond) is not a major factor of the stereoselectivity, since
an equatorial attack on the exocyclic double bond is
normally favorable over an axial attack.25
Conclusion
First of all, we could show a new utility of b-(ethoxy-
carbonyl)allylsilane as an organic bifunctional unit.
Synthesis of both spiro[4.5]decanes and spiro[4.4]nonanes
through Nazarov cyclization of 4-cycloalkylidene-5-
(trimethylsilyl)pent-1-en-3-one derivatives was established.
Also, it was clari®ed that skeletal rearrangement occurs
from spiro[4.4]nonanes to bicyclo[4.3.0]nonanes by eleva-
tion of the reaction temperature. This type of rearrangement
is limited to strained ®ve±®ve spiro ring system having exo-
methylene group. The synthesis of bicyclo[4.3.0]nonane
ring system from a compound having ®ve-membered carbo-
cycles is one of the classical method.2 However, this new
entry to bicyclo[4.3.0]nonane from ®ve-membered carbo-
cycle is completely different from the classical method,
since (1) the newly formed ring is still ®ve-membered,
and (2) the original ®ve-membered ring enlarges to six-
membered ring. This rare type of fused ring construction,
ªring-expanding annulationº, is also reported by Mock and
Hartman utilizing an intramolecular reaction of the diazo
ketone with cycloalkanone.27 We have previously reported
the synthesis of the bicyclo[4.3.0]nonane ring system from
b-(ethoxycarbonyl)allylsilane.5 The present synthetic
method of bicyclo[4.3.0]nonane ring system via spiro[4.4]-
nonanes is completely different from the previous strategy
using similarly functionalized allylsilane.
Scheme 10.

6446
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
Scheme 11. Reagents and conditions: (i) for 28a±e, (EtO)2P(O)CH(CO2Et)CH2SiMe3, NaH, DME, 708C; (i) for 28f, (EtO)2P(O)CH(CO2Et)CH3, NaH, DME,
708C; (ii) LiAlH4, Et2O, 08C; (iii) MnO2, CH2Cl2, rt; (iv) for 31a±e,k, BrMgCHvCH2, THF, rt; (iv) for 31f, BrMgCHvCHMe, THF, rt; (iv) for 31g,h,l,
BrMgCMevCH2, THF, rt; (iv) for 31i, BrMgCHvCHPh, THF, rt; (iv) for 31j, BrMgCPhvCH2, THF, rt; (iv) for 31m, BrMgCMevCHMe, THF, rt.
From the study on the substituent effect, the followings can
be concluded. First, in spite of our prediction (Scheme 2),
the double bond position in the product is controlled by the
presence/absence of a0-substituent, not by the presence/
absence of allylic silicon atom. Second, the allylic silicon
atom is essential for obtaining the products in good yields,
which must be the result of silicon-stabilization of the inter-
mediate. Third, the b0-substituent also has an effect of
increasing the yields. This implies that the alkyl substitution
pattern is also important, as well as silyl group, in the
Nazarov cyclization reaction.
Both low-resolution mass spectra (MS) and high-resolution
mass spectra (HRMS) were obtained on a Jeol SX-102A,
JMS-DX303, or Shimadzu GCMS-QP5050 mass spectro-
meter with the EI method unless otherwise noted. Analytical
TLC was done on precoated TLC plates (Kieselgel 60 F254,
layer thickness 0.2 mm). Wakogel C-200, C-300 or ICN
Alumina N Act 1 were used for column chromatography.
Anhydrous Na2SO4 or MgSO4 was used for drying of
extracted organic layers. For reactions requiring dry
solvents, tetrahydrofuran (THF), Et2O, 1,2-dimethoxy-
ethane (DME), and CH2Cl2 were distilled from CaH2.
Synthesis of 28 (Wittig reaction)
Experimental
Typical Procedure. To a stirred suspension of NaH
(613.3 mg, 15.33 mmol; 60% in mineral oil which was
removed by washing with dry hexane) in dry DME
(40 cm3) was added (EtO)2P(O)CH2CO2Et (2.75 cm3,
13.87 mmol) dropwise at 08C under Ar. After being stirred
for 40 min, ICH2SiMe3 (2.50 cm3, 16.9 mmol) was added
and the mixture was heated to 708C for 4 h. This was cooled
to 08C again, and a second portion of NaH (505.5 mg,
12.64 mmol; mineral oil was not removed) was added.
After being stirred at 08C for 2 h, a solution of cyclohexa-
none (1.2 cm3, 11.6 mmol) in DME (10 cm3) was added,
and the mixture was stirred at 708C for 6 h, then at room
temperature for 18 h. An aqueous solution of NH4Cl was
General procedures
Melting points were collected on a Laboratory Devices Mel-
Temp apparatus. UV spectra were measured on a Jasco
Ubest-50 spectrometer. IR spectra were taken on a Hitachi
270-30 or Jasco FT/IR-230 spectrometer. Both H and 13C
1
NMR spectra were measured on a Jeol GSX-400 (400 MHz
1
for H; 100 MHz for 13C) spectrometer. Chemical shifts
were reported on the d scale (ppm) with solvent
(CHCl3ˆ7.25) as an internal standard, unless otherwise
noted. The signal of the solvent (CDCl3ˆ77.0) was used
as a standard for 13C NMR spectra unless otherwise noted.

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6447
added, the mixture was extracted with Et2O, and dried.
Evaporation of the solvent followed by silica gel (30 g)
column chromatography using pentane±Et2O (99:1) as
eluent afforded 28c (1.5224 g, 52%). For the preparation
of 28f, methyl iodide was used instead of ICH2SiMe3.
Ethyl 2-(3-methylcyclopentylidene)-3-(trimethylsilyl)-
propanoate (28e). An oil; IR (neat) 1710 (CvO), 1635
;
(CvC), 1280, 1250, 1180, and 855 cm21 1H NMR
(CDCl3) 20.02 (9H£1/2, s, SiMe3), 20.02 (9H£1/2, s,
SiMe3), 1.00 (3H£1/2, d, Jˆ6.5 Hz, CHCH3), 1.00
(3H£1/2, d, Jˆ6.5 Hz, CHCH3), 1.27 (3H£1/2, t,
Jˆ7.1 Hz, OCH2CH3), 1.28 (3H£1/2, t, Jˆ7.1 Hz,
OCH2CH3), 1.14±3.00 (9H, m), 4.13 (2H£1/2, q,
Jˆ7.1 Hz, OCH2CH3), and 4.14 (2H£1/2, q, Jˆ7.1 Hz,
OCH2CH3); 13C NMR (CDCl3) 20.8 (3C£2), 14.4 (£2),
19.7 (£2) 20.3, 20.5, 33.6 (£2), 33.7, 33.8, 35.1, 35.2,
42.5, 42.7, 59.7 (£2) 121.3, 121.3, 155.5, 155.6, 168.4,
and 168.5 (for both isomers; assignment was not made);
MS m/z 254 (M1, 59%), 239 (M12Me, 71), 211 (28),
195 (42), 136 (68), and 73 (100); HRMS [Found: m/z
254.1707 (M1). Calcd for C14H26O2Si: M, 254.1703].
Ethyl 2-(4-t-butylcyclohexylidene)-3-(trimethylsilyl)pro-
panoate (28a). An oil; UV (pentane) lmaxˆ231 nm (e
7.5£103; IR (neat) 1715 (CvO), 1640 (CvC), 1450,
1
1250, 1175, and 855 cm21; H NMR (CDCl3) 20.01 (9H,
s, SiMe3), 0.83 (9H, s, t-Bu), 1.00±1.89 (7H, m), 1.29 (3H, t,
Jˆ7.2 Hz, OCH2CH3), 1.79 (2H, br s, CH2SiMe3), 2.55 (1H,
br dq, Jˆ14, 3 Hz, CvCCHH), 2.97 (1H, br dq, Jˆ14,
3 Hz, CvCCHH), and 4.15 (2H, q, Jˆ7.2 Hz, OCH2CH3);
13C NMR (CDCl3) 21.2 (3C), 14.2, 19.8, 27.5 (3C), 28.2,
28.8, 31.2, 32.1, 32.4, 48.0, 60.0, 122.3, 143.0, and 170.9;
MS m/z 310 (M1, 24%), 295 (26), 282 (31), 264 (24), 211
(29), 200 (33), and 149 (100); HRMS [Found: m/z 310.2301
(M1). Calcd for C18H34O2Si: M, 310.2329]; Analysis
[Found: C, 69.40; H, 10.75%. Calcd for C18H34O2Si: C,
69.62; H, 11.04%].
Ethyl 2-cyclohexylidenepropanoate (28f). An oil; IR
(neat) 1715 (CvO), 1640 (CvC), 1450, 1205, and
1
1105 cm21; H NMR (CDCl3, Me4Siˆ0.00) 1.30 (3H, t,
Jˆ7.1 Hz, OCH2CH3), 1.55±1.64 (6H, m), 1.86 (3H, br s,
CvCMe), 2.22 (2H, m, CvCCH2), 2.43 (2H, m,
CvCCH2), and 4.19 (2H, q, Jˆ7.1 Hz, OCH2CH3); 13C
NMR (CDCl3, Me4Siˆ0.0) 14.3, 15.1, 26.6, 27.8, 28.2,
31.2, 32.4, 60.1, 119.9, 147.4, and 170.7; MS m/z 182
(M1, 100%), 153 (48), 136 (91), 109 (78), and 55 (24);
HRMS [Found: m/z 182.1312 (M1). Calcd for C11H18O2:
M, 182.1307].
Ethyl 2-(4-methylcyclohexylidene)-3-(trimethylsilyl)pro-
panoate (28b). An oil; UV (pentane) lmaxˆ230 nm (e
6.1£103); IR (neat) 1720 (CvO), 1640 (CvC), 1460,
1
1250, 1190, and 855 cm21; H NMR (CDCl3) 20.01 (9H,
s, SiMe3), 0.88 (3H, d, Jˆ6.6 Hz, Me), 0.95±1.94 (7H, m),
1.28 (3H, t, Jˆ7.1 Hz, OCH2CH3), 1.78 (2H, s, CH2SiMe3),
2.47 (1H, m, CvCCHH), 2.86 (1H, br ddt, Jˆ14, 2.5, 4 Hz,
CvCCHH), and 4.15 (2H, q, Jˆ7.1 Hz, OCH2CH3); 13C
NMR (CDCl3) 21.2 (3C), 14.2, 19.9, 21.8, 30.6, 31.7,
32.5, 35.7, 36.3, 60.1, 122.7, 142.3, and 171.0; MS m/z
268 (M1, 15%), 253 (10), 220 (43), and 205 (100);
HRMS [Found: m/z 268.1864 (M1). Calcd for
C15H28O2Si: M, 268.1859]; Analysis [Found: C, 66.98; H,
10.23%. Calcd for C15H28O2Si: C, 67.11; H, 10.51%].
Synthesis of 29 (LiAlH4 reduction)
Typical procedure. To a stirred suspension of LiAlH4
(145 mg, 3.82 mmol) in dry Et2O (35 cm3) was added a
solution of 28c (322.5 mg, 1.268 mmol) in Et2O (10 cm3)
at 08C, and the mixture was stirred for 30 min under CaCl2
drying tube. The reaction was quenched by successive addi-
tion of wet Et2O and water. A dilute solution of HCl (ca.
1 mol dm23) was added and the resulted clear solution was
extracted with CH2Cl2 and dried. Evaporation of the solvent
followed by silica gel (20 g) column chromatography using
pentane±Et2O (98:2) as eluent afforded 29c (254.9 mg,
95%).
Ethyl 2-cyclohexylidene-3-(trimethylsilyl)propanoate (28c).
An oil; UV (pentane) lmaxˆ230 nm (e 8.2£103); IR (neat)
1715 (CvO), 1645 (CvC), 1450, 1250, 1210, 1150, and
1
855 cm21; H NMR (CDCl3) 20.01 (9H, s, SiMe3), 1.28
(3H, t, Jˆ7.2 Hz, OCH2CH3), 1.50±1.59 (6H, m, (CH2)3),
1.78 (2H, s, CH2SiMe3), 2.12 (2H, m, CvCCH2), 2.36 (2H,
C
m, CvCCH2), and 4.15 (2H, q, Jˆ7.2 Hz, OCH2CH3); 13
2-(4-t-Butylcyclohexylidene)-3-trimethylsilyl-1-propanol
(29a). An oil; IR (neat) 3340 (OH), 1650 (CvC), 1370,
NMR (CDCl3) 21.2 (3C), 14.2, 19.8, 26.6, 27.6, 28.2, 31.3,
32.5, 60.1, 122.6, 142.7, and 171.0; MS m/z 254 (M1, 18%),
239 (17), 226 (21), 211 (44), 136 (86), 108 (66), and 73
(100); HRMS [Found: m/z 254.1686 (M1). Calcd for
C14H26O2Si: M, 254.1703].
1
1250, 990, and 850 cm21; H NMR (CDCl3) 0.00 (9H, s,
SiMe3), 0.83 (9H, s, t-Bu), 0.92±1.89 (9H, m), 2.53 (1H, br
dq, Jˆ14, 3 Hz, CvCCHH), 2.79 (1H, br dq, Jˆ14, 3 Hz,
CvCCHH), 4.02 (1H, br d, Jˆ11 Hz, CHHOH), and 4.06
(1H, br d, Jˆ11 Hz, CHHOH); 13C NMR (CDCl3) 20.8
(3C). 21.4, 27.6 (3C), 28.3, 29.3, 30.0, 31.0, 32.4, 48.3,
63.5, 126.6, and 135.1; MS m/z 268 (M1, 11%), 253 (3),
237 (35), 178 (16), 163 (21), 123 (37), and 73 (100); HRMS
[Found: m/z 268.2204 (M1). Calcd for C16H32OSi: M,
268.2224].
Ethyl 2-cyclopentylidene-3-(trimethylsilyl)propanoate (28d).
An oil; UV (pentane) lmaxˆ239 nm (e 5.6£103); IR (neat)
1710 (CvO), 1635 (CvC), 1280, 1250, 1170, and
1
855 cm21; H NMR (CDCl3) 20.03 (9H, s, SiMe3), 1.27
(3H, t, Jˆ7.1 Hz, OCH2CH3), 1.58±1.70 (4H, m,
CH2CH2), 1.76 (2H, br s, CH2SiMe3), 2.26 (2H, br t,
Jˆ7 Hz, CvCCH2), 2.68 (2H, br t, Jˆ7 Hz, CvCCH2),
and 4.13 (2H, q, Jˆ7.1 Hz, OCH2CH3); 13C NMR (CDCl3)
20.9 (3CH3), 14.4 (CH3), 20.6 (CH2), 25.7 (CH2), 27.2 (CH2)
34.0 (CH2), 34.3 (CH2), 59.7 (CH2), 121.2 (C), 155.6 (C),
and 168.5 (CO); MS m/z 240 (M1, 37%), 225 (46), 211 (17),
195 (27), 181 (20), 122 (88), and 73 (100); HRMS [Found:
m/z 240.1514 (M1). Calcd for C13H24O2Si: M, 240.1546].
2-(4-Methylcyclohexylidene)-3-trimethylsilyl-1-propanol
(29b). An oil; IR (neat) 3340 (OH), 1650 (CvC), 1455,
1
1250, 1000, and 850 cm21; H NMR (CDCl3) 20.01 (9H,
s, SiMe3), 0.83±1.84 (9H, m), 0.87 (3H, d, Jˆ6.6 Hz, Me),
2.45 (1H, br dq, Jˆ14, 3 Hz, CvCCHH), 2.69 (1H, br dq,
Jˆ14, 3 Hz, CvCCHH), and 4.03 (2H, br s, CH2OH); 13C
NMR (CDCl3) 20.8 (3C), 21.5, 22.0, 29.5, 30.5, 32.7, 36.0,

6448
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
36.9, 63.5, 127.0, and 134.8; MS m/z 226 (M1, 3%), 208 (5),
193 (5), 136 (33), 121 (59), 107 (49), 93 (94), and 73 (100);
HRMS [Found: m/z 226.1764 (M1). Calcd for C13H26OSi:
M, 226.1754].
(CvC), 1250, and 860 cm21; 1H NMR (CDCl3) 20.06 (9H,
s, SiMe3), 0.85 (9H, s, t-Bu), 1.08±2.03 (7H, m), 1.72 (1H,
br d, Jˆ13 Hz, CHHSiMe3), 1.81 (1H, br d, Jˆ13 Hz,
CHHSiMe3), 2.75 (1H, br dq, Jˆ13, 2.5 Hz, CvCCHH),
3.52 (1H, br dq, Jˆ13, 2.5 Hz, CvCCHH), and 10.15 (1H,
s, CHO); 13C NMR (CDCl3) 21.0 (3C), 15.0, 27.5 (3C),
28.4, 28.7, 29.4, 32.4, 33.5, 48.0, 132.0, 158.7, and 190.1;
MS m/z 266 (M1, 79%), 251 (84), 237 (36), 209 (68), 167
(43), 119 (40), and 73 (100); HRMS [Found: m/z 266.2096
(M1). Calcd for C16H30OSi: M, 266.2067].
2-Cyclohexylidene-3-trimethylsilyl-1-propanol (29c). An
oil; IR (neat) 3340 (OH), 1650 (CvC), 1450, 1250, 995,
1
and 850 cm21; H NMR (CDCl3) 20.01 (9H, s, SiMe3),
1.46±1.57 (6H, m, (CH2)3), 1.65 (2H, s, CH2SiMe3), 2.07
(2H, m, CvCCH2), 2.23 (2H, m, CvCCH2), and 4.02 (2H,
s, CH2OH); 13C NMR (CDCl3) 20.8 (3C), 21.3, 26.8, 27.8,
28.7, 30.2, 31.2, 63.3, 126.9, and 135.2; MS m/z 212 (M1,
14%), 197 (9), 167 (17), 149 (36), 122 (27), 107 (43), 93
(52), and 73 (100); HRMS [Found: m/z 212.1596 (M1).
Calcd for C12H24OSi: M, 212.1597].
2-(4-Methylcyclohexylidene)-3-(trimethylsilyl)propanal
(30b). An oil; IR (neat) 2770 (CHO), 1670 (CvO), 1615
(CvC), 1250, and 855 cm21; 1H NMR (CDCl3) 20.06 (9H,
s, SiMe3), 0.91 (3H, d, Jˆ6.6 Hz, Me), 1.03±2.12 (7H, m),
1.74 (1H, br d, Jˆ13 Hz, CHHSiMe3), 1.80 (1H, br d,
Jˆ13 Hz, CHHSiMe3), 2.67 (1H, br dq, Jˆ14, 2 Hz,
CvCCHH), 3.41 (1H, br dq, Jˆ14, 2 Hz, CvCCHH),
and 10.15 (1H, s, CHO); 13C NMR (CDCl3) 21.0 (3C),
15.1, 21.6, 28.3, 32.6, 33.0, 35.8, 36.8, 132.4, 158.5, and
190.2; MS m/z 224 (M1, 34%), 209 (59), 195 (12), 181 (16),
167 (28), 119 (18), and 73 (100); HRMS [Found: m/z
224.1600 (M1). Calcd for C13H24OSi: M, 224.1597].
2-Cyclopentylidene-3-trimethylsilyl-1-propanol (29d).
An oil; IR (neat) 3350 (OH), 1670 (CvC), 1420, 1250,
1
1010, 980, and 850 cm21; H NMR (CDCl3) 0.01 (9H, s,
SiMe3), 1.59 (2H, br s, CH2SiMe3), 1.56±1.67 (4H, m,
CH2CH2), 2.12 (2H, m, CvCCH2), 2.29 (2H, m,
CvCCH2), and 4.05 (2H, br s, CH2OH); 13C NMR
(CDCl3) 20.0 (3C), 21.7, 26.4, 27.0, 29.9, 31.5, 64.8,
127.1, and 138.2; MS m/z 198 (M1, 15%), 181 (8), 165
(7), 108 (95), and 80 (100); HRMS [Found: m/z 198.1418
(M1). Calcd for C11H22OSi: M, 198.1441].
2-Cyclohexylidene-3-(trimethylsilyl)propanal (30c). An
oil; IR (neat) 2770 (CHO), 1670 (CvO), 1615 (CvC),
1250, and 855 cm21 1H NMR (CDCl3) 20.05 (9H, s,
;
2-(3-Methylcyclopentylidene)-3-trimethylsilyl-1-propanol
(29e). An oil; IR (neat) 3340 (OH), 1670 (CvC), 1250, 990,
SiMe3), 1.59±1.69 (6H, m, (CH2)3), 1.78 (2H, s, CH2SiMe3),
2.32 (2H, m, CvCCH2), 2.73 (2H, m, CvCCH2), and 10.17
(1H, s, CHO); 13C NMR (CDCl3) ±1.0 (3C), 14.9, 26.5,
27.9, 28.8, 29.1, 33.7, 132.2, 158.7, and 190.0; MS m/z
210 (M1, 32%), 195 (48), 181 (12), 167 (17), and 73
(100); HRMS [Found: m/z 210.1405 (M1). Calcd for
C12H22OSi: M, 210.1441]; Analysis as semicarbazone (mp
187±1888C) [Found: C, 58.32; H, 9.17; N, 15.63%. Calcd
for C13H25N3OSi: C, 58.38; H, 9.42; N, 15.71%].
1
and 850 cm21; H NMR (CDCl3) 0.01 (9H£1/2, s, SiMe3),
0.01 (9H£1/2, s, SiMe3), 0.98 (3H£1/2, d, Jˆ6.5 Hz,
CHCH3), 0.99 (3H£1/2, d, Jˆ6.5 Hz, CHCH3), 1.57 (2H,
br s, CH2SiMe3), 1.13±2.56 (7H, m), and 4.03 (2H, br s,
CH2OH); 13C NMR (CDCl3) 20.6 (3C£2), 19.9 19.9, 21.5,
21.7, 29.5, 31.1, 34.4, 34.4, 34.9, 35.0, 38.5, 40.1, 64.5,
64.8, 127.2, 127.3, 138.1, and 138.1 (for both isomers;
assignment was not made); MS m/z 212 (M1, 8%), 122
(46), 107 (75), 93 (100), and 75 (99); HRMS [Found: m/z
212.1584 (M1). Calcd for C12H24OSi: M, 212.1597].
2-Cyclopentylidene-3-(trimethylsilyl)propanal (30d). An
oil; IR (neat) 2760 (CHO), 1670 (CvO), 1630 (CvC),
1250, and 855 cm21 1H NMR (CDCl3) ±0.05 (9H, s,
;
2-Cyclohexylidene-1-propanol (29f). An oil; IR (neat)
SiMe3), 1.66 (2H, br s, CH2SiMe3), 1.64±1.82 (4H, m,
CH2CH2), 2.41 (2H, br t, Jˆ7 Hz, CvCCH2), 2.81 (2H,
br t, Jˆ7 Hz, CvCCH2), and 9.94 (1H, s, CHO); 13C
NMR (CDCl3) 0.0 (3C), 16.8, 24.9, 27.0, 29.7, 34.2,
132.0, 164.2, and 191.5; MS m/z 196 (M1, 62%), 181
(100), 113 (15), and 73 (95); HRMS [Found: m/z
196.1329 (M1). Calcd for C11H20OSi: M, 196.1284]; Analy-
sis as semicarbazone (mp 178±1808C) [Found: C, 56.84; H,
8.97; N, 16.64%. Calcd for C12H23N3OSi: C, 56.88; H, 9.15;
N, 16.58%].
1
3340 (OH), 1655 (CvC), 1445, and 1000 cm21; H NMR
(CDCl3, Me4Siˆ0.00) 1.48±1.56 (6H, m), 1.77 (3H, s,
CvCMe), 2.17 (2H, m, CvCCH2), 2.24 (2H, m,
CvCCH2), and 4.13 (2H, s, CH2OH); 13C NMR (CDCl3)
16.2, 26.8, 27.8, 28.5, 30.2, 30.8, 63.4, 124.2, and 137.9; MS
m/z 140 (M1, 13%), 122 (79), 107 (72), 93 (60), 79 (100),
and 67 (89); HRMS [Found: m/z 140.1221 (M1). Calcd for
C9H16O: M, 140.1202].
Synthesis of 30 (MnO2 oxidation)
2-(3-Methylcyclopentylidene)-3-(trimethylsilyl)propanal
(30e). An oil; IR (neat) 2760 (CHO), 1670 (CvO), 1635
Typical procedure. Compound 29c (254.9 mg, 1.200 mmol)
was dissolved in dry CH2Cl2 (50 cm3) and to this was added
an excess amount of MnO2 (10.22 g). The resulting suspen-
sion was stirred at room temperature under a CaCl2 drying
tube for 4 days, and then ®ltered through Celite. The ®ltrate
was evaporated under reduced pressure to give an oily resi-
due, which was chromatographed on silica gel (20 g) using
pentane±Et2O (99:1) as eluent to afford 30c (191.2 mg, 76%).
1
(CvC). 1250, and 855 cm21; H NMR (CDCl3) 20.04
(9H£1/2, s, SiMe3), 20.04 (9H£1/2, s, SiMe3), 1.05
(3H£1/2, d, Jˆ6.2 Hz, CHCH3), 1.06 (3H£1/2, d,
Jˆ6.3 Hz, CHCH3), 1.20±3.13 (7H, m), 1.65 (2H, br s,
CH2SiMe3), 9.91 (1H£1/2, s, CHO), and 9.93 (1H£1/2, s,
CHO); 13C NMR (CDCl3) 20.7 (3C£2), 16.6, 16.8, 19.6,
19.6, 29.3, 32.7, 33.1, 33.7, 34.7, 35.3, 38.1, 42.6, 100.2
(£2), 132.0 (£2), 191.5, and 191.5 (for both isomers; assign-
ment was not made); MS m/z 210 (M1, 30%), 195
(M12Me, 60), 181 (13), 113 (15), 105 (15), and 73 (100);
2-(4-t-Butylcyclohexylidene)-3-(trimethylsilyl)proponal
(30a). An oil; IR (neat) 2770 (CHO), 1670 (CvO), 1615

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6449
HRMS [Found: m/z 210.1405 (M1). Calcd for C12H22OSi:
M, 210.1441].
17.1 Hz, CHvCH2), and 5.85 (1H£1/2, ddd, Jˆ4.8, 10.4,
17.2 Hz, CHvCH2); 13C NMR (CDCl3) 20.2 (3C£2), 17.4,
17.7, 22.0, 22.1, 29.5, 29.6, 31.1, 31.4, 32.8, 32.9, 35.9,
36.0, 36.4, 36.6, 72.2, 72.6, 113.7, 113.8, 133.2 (£2),
139.6, 139.9, and 149.7 (£2) (for both isomers; assignment
was not made); MS m/z 252 (M1, 25%), 234 (55), 209 (100),
167 (39), and 136 (85); HRMS [Found: m/z 252.1868 (M1).
Calcd for C15H28OSi: M, 252.1910].
2-Cyclohexylidenepropanal (30f). An oil; IR (neat) 2770
(CHO), 1665 (CvO), 1625 (CvC), 1445, 1315, and
1285 cm21
;
1H NMR (CDCl3, Me4Siˆ0.00) 1.63±1.73
(6H, m), 1.76 (3H, s, Me), 2.40 (2H, m, CvCCH2), 2.74
(2H, m, CvCCH2), and 10.19 (1H, s, CHO); 13C NMR
(CDCl3) 10.3, 26.4, 27.9, 28.7, 29.1, 33.3, 129.4, 162.6,
and 190.5; MS m/z 138 (M1, 100%), 123 (30), 109 (69),
95 (96), 81 (48), 67 (54), and 41 (84); HRMS [Found: m/z
138.1034 (M1). Calcd for C9H14O: M, 138.1045]; Analysis
as semicarbazone (mp 197±2018C) [Found: C, 61.25; H,
8.65; N, 21.44%. Calcd for C10H17N3O: C, 61.51; H, 8.78;
N, 21.52%].
4-Cyclohexylidene-5-(trimethylsilyl)pent-1-en-3-ol (31c).
An oil; IR (neat) 3420 (OH), 1640 (CvC), 1450, 1250,
1030, and 850 cm21 1H NMR (CDCl3) 0.01 (9H, s,
;
SiMe3), 1.4±1.6 (8H, m), 2.06 (2H, m, CvCCH2), 2.24
(2H, m, CvCCH2), 5.06 (1H, m, CHOH), 5.09 (1H, dt,
Jˆ10.4, 1.7 Hz, CvCHH), 5.22 (1H, dt, Jˆ17.2, 1.7 Hz,
CvCHH), and 5.85 (1H, ddd, Jˆ4.9, 10.4, 17.2 Hz,
CHvCH2); 13C NMR (CDCl3) 20.2 (3C), 17.4, 26.9,
27.7, 28.3, 30.3, 31.9, 72.2, 113.7, 128.0, 133.4, and
139.8; MS m/z 238 (M1, 3%), 205 (9), 195 (10), 148 (30),
133 (43), 119 (47), 106 (100), and 80 (89); HRMS
[Found: m/z 238.1752 (M1). Calcd for C14H26OSi: M,
238.1754].
Synthesis of 31 (Grignard reaction)
Typical procedure. To a stirred solution of 30c (83.1 mg,
0.39 mmol) in dry THF (20 cm3) was added a solution of
vinylmagnesium
bromide
(1.95 cm3,
1.95 mmol;
1 mol dm23 solution in THF) at 08C under Ar. After being
stirred for 1 h, an aqueous solution of NH4Cl was added, and
the mixture was extracted with AcOEt. Drying and evapora-
tion of the solvent gave a crude product containing 31c,
which was not puri®ed.
4-Cyclopentylidene-5-(trimethylsilyl)pent-1-en-3-ol (31d).
An oil; IR (neat) 3420 (OH), 1645 (CvC), 1420, 1250, 995,
and 855 cm21; 1H NMR (CDCl3) 0.01 (9H, s, SiMe3), 1.5±
1.7 (6H, m), 2.0±2.4 (4H, m), 4.86 (1H, br d, Jˆ5 Hz,
CHOH), 5.08 (1H, dt, Jˆ10.5, 1.6 Hz, CvCHH), 5.22
(1H, dt, Jˆ17.2, 1.6 Hz, CvCHH), and 5.83 (1H, ddd,
Jˆ5.3, 10.5, 17.2 Hz, CHvCH2); 13C NMR (CDCl3) 0.0
(3CH3), 18.8 (CH2), 26.2 (CH2), 27.0 (CH2), 29.9 (CH2),
32.0 (CH2), 74.2 (CH), 113.9 (CH2), 128.5 (C), 136.9 (C),
and 139.0 (CH); MS m/z 224 (M1, 11%), 209 (2), 191 (9),
134 (80), 119 (70), 106 (100), and 92 (80); HRMS
[Found: m/z 224.1629 (M1). Calcd for C13H24OSi: M,
224.1597].
This type of dienols 31a±m were not stable enough for
puri®cation on silica gel, and were used in the next MnO2
oxidation without puri®cation. The following spectral data
were collected after careful puri®cation by silica gel or
alumina column chromatography, however it was not
possible to obtain pure compound in some cases. For (Z)-
31f and (E)-31f, separation from each other was made for
only spectral purpose.
4-(4-t-Butylcyclohexylidene)-5-(trimethylsilyl)pent-1-en-
3-ol (31a). An oil; IR (neat) 3450 (OH), 1645 (CvC), 1370,
1250, 1030, and 855 cm21; 1H NMR (CDCl3) 0.01 (9H£1/2,
s, SiMe3), 0.01 (9H£1/2, s, SiMe3), 0.82 (9H£1/2, s, t-Bu),
0.83 (9H£1/2, s, t-Bu), 0.9±1.9 (9H, m), 2.49 (1H, m,
CvCCHH), 2.82 (1H, m, CvCCHH), 5.08 (2H, m,
CvCHH and CHOH), 5.21 (1H£1/2, dt, Jˆ17.2, 1.6 Hz,
CvCHH), 5.23 (1H£1/2, dt, Jˆ17.2, 1.6 Hz, CvCHH),
5.84 (1H£1/2, ddd, Jˆ5.1, 10.6, 17.2 Hz, CHvCH2), and
5.86 (1H£1/2, ddd, Jˆ4.9, 10.5, 17.2 Hz, CHvCH2); 13C
NMR (CDCl3) 20.1 (3C£2), 17.4, 17.5, 27.5 (3C£2), 28.2,
28.3, 28.8, 29.0, 30.0, 30.1, 31.6, 31.9, 32.4 (£2), 48.3, 48.4,
72.2, 72.5, 113.7, 113.7, 127.6, 127.9, 133.2, 133.5, 139.6,
and 140.0 (for both isomers; assignment was not made); MS
m/z 294 (M1, 4%), 279 (5), 268 (3), 261 (3), 237 (62), 209
(19), 147 (18), 106 (67), and 73 (100); HRMS [Found: m/z
294.2373 (M1). Calcd for C18H34OSi: M, 294.2380].
4-(3-Methylcyclopentylidene)-5-(trimethylsilyl)pent-1-en-
3-ol (31e). An oil; IR (neat) 3400 (OH), 1640 (CvC), 1245,
1
1020, and 850 cm21; H NMR (CDCl3) 0.02 (9H£3/4, s,
SiMe3), 0.02 (9H£1/4, s, SiMe3), 0.98 (3H£1/2, d,
Jˆ6.4 Hz, CHCH3), 0.99 (3H£1/4, d, Jˆ6.4 Hz, CHCH3),
1.00 (3H£1/4, d, Jˆ6.5 Hz, CHCH3), 1.1±2.6 (9H, m), 4.85
(1H, br, CHOH), 5.09 (1H, m, CvCHH), 5.23 (1H, m,
CvCHH), and 5.84 (1H, m, CHvCH2); MS m/z 238
(M1, 2%), 220 (28), 205 (36), 133 (47), 93 (66), and 73
(100); HRMS [Found: m/z 238.1799 (M1). Calcd for
C14H26OSi: M, 238.1754].
(Z)-2-Cyclohexylidene-1-(trimethylsilyl)hex-4-en-3-ol ((Z)-
31f). An oil; IR (neat) 3460 (OH), 1655 (CvC), 1450, 1245,
1
and 850 cm21; H NMR (C6D6ˆ7.15) 0.16 (9H, s, SiMe3),
1.42±1.57 (6H, m), 1.52 (3H, dd, Jˆ1.7, 6.9 Hz, CH3), 1.67
(1H, br d, Jˆ14 Hz, CHHSiMe3), 1.71 (1H, br d, Jˆ14 Hz,
CHHSiMe3), 2.07 (2H, m, CvCCH2), 2.22 (2H, m,
CvCCH2), 5.32 (1H, br d, Jˆ8 Hz, CHOH), 5.35 (1H,
ddq, Jˆ1.4, 10.7, 6.9 Hz, CHvCHCH3), and 5.63 (1H,
ddq, Jˆ8.2, 10.7, 1.7 Hz, CHvCHCH3); 13C NMR
(C6D6ˆ128.0) 0.1 (3C), 13.3, 17.9, 27.3, 28.1, 28.6, 30.6,
32.1, 67.2, 124.7, 130.2, 131.9, and 133.6; MS m/z 252 (M1,
3%), 234 (21), 219 (13), 205 (8), 160 (22), 147 (60), and 75
(100); HRMS [Found: m/z 252.1942 (M1). Calcd for
C15H28OSi: M, 252.1910].
4-(4-Methylcyclohexylidene)-5-(trimethylsilyl)pent-1-en-
3-ol (31b). An oil; IR (neat) 3430 (OH), 1645 (CvC), 1460,
1
1250, and 850 cm21; H NMR (CDCl3) 0.01 (9H£1/2, s,
SiMe3), 0.01 (9H£1/2, s, SiMe3), 0.8±1.9 (9H, m), 0.86
(3H£1/2, d, Jˆ6.6 Hz, Me), 0.87 (3H£1/2, d, Jˆ6.6 Hz,
Me), 2.50 (1H, m, CvCCHH), 2.82 (1H, m, CvCCHH),
5.06 (2H, m, CvCHH and CHOH), 5.21 (1H£1/2, dt,
Jˆ17.2, 1.7 Hz, CvCHH), 5.23 (1H£1/2, dt, Jˆ17.2,
1.7 Hz, CvCHH), 5.83 (1H£1/2, ddd, Jˆ4.9, 10.4,

6450
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
(E)-2-Cyclohexylidene-1-(trimethylsilyl)hex-4-en-3-ol ((E)-
31f). An oil; IR (neat) 3420 (OH), 1655 (CvC), 1450, 1245,
1H NMR (CDCl3) 1.40±1.62 (6H, m), 1.58 (3H, s, Me),
2.03±2.24 (4H, m, CvCCH2£2), 5.08 (1H, m, CvCHH),
5.20 (1H, m, CHOH), 5.22 (1H, m, CvCHH), and 5.84 (1H,
m, CHvCH2); 13C NMR (C6D6ˆ128.0) 11.8, 27.2, 28.1,
28.6, 30.3, 31.3, 71.0, 113.2, 126.0, 135.5, and 140.2; MS
m/z 166 (M1, 60%), 148 (100), 133 (97), 109 (84), 95 (84),
and 83 (89); HRMS [Found: m/z 166.1308 (M1). Calcd for
C11H18O: M, 166.1358].
1
and 850 cm21; H NMR (C6D6ˆ7.15) 0.15 (9H, s, SiMe3),
1.40±1.52 (6H, m), 1.55 (3H, dd, Jˆ1.0, 4.7 Hz, CH3), 1.64
(1H, br d, Jˆ14 Hz, CHHSiMe3), 1.66 (1H, br d, Jˆ14 Hz,
CHHSiMe3), 2.08 (2H, m, CvCCH2), 2.19 (2H, m,
CvCCH2), 4.94 (1H, br d, Jˆ3 Hz, CHOH), and 5.46±
5.59 (2H, m, CHvCH); 13C NMR (C6D6ˆ128.0) 0.1
(3C), 17.6, 17.7, 27.3, 28.1, 28.7, 30.5, 32.2, 71.8, 124.6,
129.7, 131.7, and 133.9; MS m/z 252 (M1, 3%), 251
(M12H, 6), 234 (56), 219 (52), 160 (15), 149 (24), and
73 (100); HRMS [Found: m/z 252.1914 (M1). Calcd for
C15H28OSi: M, 252.1910].
4-Cyclohexylidene-2-methylpent-1-en-3-ol (31l). An oil;
IR (neat) 3380 (OH), 1655 (CvC), 1450, 1050, and
1
895 cm21; H NMR (CDCl3, Me4Siˆ0.00) 1.42±1.63 (6H,
m), 1.51 (3H, br s, CringvCCH3), 1.58 (3H, br s,
CH2vCCH3), 2.05±2.37 (4H, m, CvCCH2£2), 4.89 (1H,
sext, Jˆ1.6 Hz, CvCHH), and 5.07 (2H, m, CHOH and
CvCHH); 13C NMR (CDCl3) 10.9, 19.8, 26.9, 27.9, 28.3,
30.3, 31.3, 72.7, 109.0, 124.0, 137.6, and 146.1; MS (CI
method, isobutane) m/z 181 (M11H, 7%) and 163
(M12OH, 100); HRMS [Found m/z 163.1487 (M12OH).
Calcd for C12H19: M, 163.1488].
4-Cyclohexylidene-2-methyl-5-(trimethylsilyl)pent-1-en-
3-ol (31g). An oil; IR (neat) 3480 (OH), 1655 (CvC), 1450,
1245, and 855 cm21; 1H NMR (CDCl3) 0.01 (9H, s, SiMe3),
1.38±1.60 (8H, m), 1.61 (3H, br s, CH3), 1.98±2.34 (4H, m,
CvCCH2£2), 4.89 (1H, sext, Jˆ1.5 Hz, CvCHH), 5.00
(1H, br s, CHOH), and 5.05 (1H, m, CvCHH); 13C NMR
(CDCl3) 20.2 (3C), 16.4, 19.9, 26.9, 27.7, 28.2, 30.4, 32.1,
73.4, 109.3, 127.4, 133.8, and 146.5; MS m/z 234
(M1±H2O, 1%), 219 (1), 161 (4), 147 (26), 133 (15), 120
(28), 107 (71), and 73 (100); HRMS [Found: m/z 234.1779
(M12H2O). Calcd for C15H26Si: M, 234.1805].
(Z)- and (E)-2-Cyclohexylidene-4-methylhex-4-en-3-ol
(31m). An oil; IR (neat) 3360 (OH), 1655 (CvC), 1450,
1
1375, and 1000 cm21; H NMR (C6D6ˆ7.15) 1.35±1.51
(6H plus 3H£2/5, m), 1.57±1.61 (3H, m, CH3CHvCCH3),
1.61 (3H£2/5, br s, CringvCCH3 of E-isomer), 1.76
(3H£3/5, br s, CringvCCH3 of Z-isomer), 1.79 (3H£3/5,
quint, Jˆ1.4 Hz, CH3CHvCCH3 of Z-isomer), 2.01±2.22
(4H, m, CvCCH2£2), 4.94 (1H£2/5, br s, CHOH of
E-isomer), 5.23 (1H£3/5, q quint, Jˆ6.9, 1.4 Hz, CvCH
of Z-isomer), 5.36 (1H£3/5, br s, CHOH of Z-isomer), and
5.76 (1H£2/5, q quint, Jˆ6.8, 1.5 Hz, CvCH of E-isomer);
MS m/z 194 (M1, 44%), 176 (100), 161 (87), and 137 (77);
HRMS [Found: m/z 194.1681 (M1). Calcd for C13H22O: M,
194.1672].
4-Cyclopentylidene-2-methyl-5-(trimethylsilyl)pent-1-en-
3-ol (31h). An oil; IR (neat) 3480 (OH), 1655 (CvC), 1245,
and 850 cm21; 1H NMR (CDCl3) 0.02 (9H, s, SiMe3), 1.39±
1.68 (6H, m), 1.61 (3H, br s, Me), 2.11 (2H, m, CvCCH2),
2.26 (1H, m, CvCCHH), 2.40 (1H, m, CvCCHH), 4.79
(1H, br s, CHOH), 4.89 (1H, sext, Jˆ1.6 Hz, CvCHH), and
5.03 (1H, m, CvCHH); 13C NMR (CDCl3) 0.0 (3C), 18.2,
19.7, 26.3, 27.1, 30.3, 32.1, 76.0, 109.2, 127.9, 138.0, and
146.3; MS (CI method, isobutane) m/z 239 (M11H, 2%),
and 221 (M12OH, 100); HRMS [Found m/z 221.1723
(M12OH). Calcd for C14H25Si: M, 221.1727].
Synthesis of divinyl ketones (MnO2 oxidation)
(E)-4-Cyclohexylidene-1-phenyl-5-(trimethylsilyl)pent-1-
en-3-ol (31i). An oil; IR (neat) 3370 (OH), 1600 (CvC),
1450, 1245, 855, and 695 cm21; 1H NMR (C6D6ˆ7.15) 0.25
(9H, s, SiMe3), 1.35±1.70 (12H, m), 4.24 (1H, m, CHOH),
6.19 (1H, dd, Jˆ5.0, 16.0 Hz, CHvCHPh), 6.74 (1H, dd,
Jˆ1.6, 16.0 Hz, CHvCHPh), and 7.00±7.31 (5H, m, Ph);
MS m/z 314 (M1, 89%), 299 (97), 279 (98), 229 (100), 192
(99), 160 (99), and 136 (99); HRMS [Found: m/z 314.2021
(M1). Calcd for C20H30OSi: M, 314.2067].
Typical procedure. The crude compound 31c, obtained
above, was subjected to the same procedure described for
29. Puri®cation of the product was carried out by silica gel
(ca. 10 g) column chromatography using hexane±AcOEt
(99.5:0.5) as eluent to yield 3 (47.8 mg, 51% from 30c).
4-(4-t-Butylcyclohexylidene)-5-(trimethylsilyl)pent-1-en-
3-one (1). An oil; IR (neat) 1670 (CvO), 1610 (CvC),
1
1250, 860, and 840 cm21; H NMR (CDCl3) 20.03 (9H,
s, SiMe3), 0.83 (9H, s, t-Bu), 0.91±1.91 (7H, m), 1.70
(1H, br d, Jˆ14 Hz, CHHSiMe3), 1.76 (1H, br d,
Jˆ14 Hz, CHHSiMe3), 2.49 (1H, m, CvCCHH), 2.58
(1H, br dq, Jˆ14, 3 Hz, CvCCHH), 5.83 (1H, dd, Jˆ1.6,
10.3 Hz, CvCHH), 6.19 (1H, dd, Jˆ1.6, 17.5 Hz,
CvCHH), and 6.42 (1H, dd, Jˆ10.3, 17.5 Hz,
CHvCH2); 13C NMR (CDCl3) 20.9 (3CH3), 20.4 (CH2),
27.5 (3CH3), 28.3 (CH2), 28.7 (CH2), 30.8 (CH2), 32.4 (C),
32.7 (CH2), 47.9 (CH), 128.9 (CH2), 129.5 (C), 137.4 (CH),
138.7 (C), and 200.8 (CO); MS m/z 292 (M1, 4%), 274 (11),
259 (4), 237 (13), 217 (34), 147 (22), 123 (32), 106 (64), and
73 (100); HRMS [Found: m/z 292.2216 (M1). Calcd for
C18H32OSi: M, 292.2224].
4-Cyclohexylidene-2-phenyl-5-(trimethylsilyl)pent-1-en-
3-ol (31j). An oil; IR (neat) 3470 (OH), 1630 (CvC), 1490,
1445, 1245, 853, and 700 cm21; 1H NMR (CDCl3) 0.01 (9H,
s, SiMe3), 1.10±2.24 (12H, m), 5.33 (1H, t, Jˆ1.5 Hz,
CvCHH), 5.39 (1H, t, Jˆ1.5 Hz, CvCHH), 5.60 (1H, br
t, Jˆ1.5 Hz, CHOH), and 7.23±7.33 (5H, m, Ph); 13C NMR
(CDCl3) 20.1 (3C), 17.1, 26.8, 27.6, 27.8, 30.6, 32.1, 72.1,
113.1, 127.0, 127.1 (2C), 127.3, 128.0 (2C), 134.6, 140.3,
and 150.2; MS m/z 296 (M1-H2O, 10%), 278 (30), 224 (33),
209 (30), 195 (25), 169 (61), 91 (48), 73 (78), and 57 (100);
HRMS [Found: m/z 296.1962 (M1-H2O). Calcd for
C20H28Si: M, 296.1961].
4-Cyclohexylidenepent-1-en-3-ol (31k). An oil; IR (neat)
;
4-(4-Methylcyclohexylidene)-5-(trimethylsilyl)pent-1-en-
3-one (2). An oil; IR (neat) 1670 (CvO), 1610 (CvC),
3410 (OH), 1640 (CvC), 1450, 1055, 990, and 920 cm21

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6451
1265, and 800 cm21
;
1H NMR (CDCl3) 20.02 (9H, s,
10.2 Hz, CvCHH), 6.19 (1H, dd, Jˆ1.9, 17.2 Hz,
CvCHH), and 6.64 (1H, dd, Jˆ10.2, 17.2 Hz,
CHvCH2); 13C NMR (CDCl3) 20.9 (3C), 19.8, 21.4, 33.6
(2C), 35.4, 41.9, 127.5, 131.1, 136.2, 150.0, and 196.1; MS
m/z 236 (M1, 7%), 220 (86), 205 (100), and 57 (32); HRMS
[Found: m/z 236.1609 (M1). Calcd for C14H24OSi: M,
236.1597].
SiMe3), 0.89 (3H, d, Jˆ6.6 Hz, Me), 0.8721.90 (9H, m),
2.41 (1H, m, CvCCHH), 2.50 (1H, m, CvCCHH), 5.84
(1H, dd, Jˆ1.7, 10.3 Hz, CvCHH), 6.19 (1H, dd, Jˆ1:7,
17.6 Hz, CvCHH), and 6.41 (1H, dd, Jˆ10.3, 17.6 Hz,
CHvCH2); 13C NMR (CDCl3) 20.9 (3C), 20.5, 21.9,
30.2, 32.1, 32.4, 35.8, 36.2, 129.0, 129.9, 137.3, 138.1,
and 200.9; MS m/z 250 (M1, 24%), 235 (34), 208 (17),
193 (28), 182 (36), and 73 (100); HRMS [Found: m/z
250.1800 (M1). Calcd for C15H26OSi: M, 250.1754].
(Z)-2-Cyclohexylidene-1-(trimethylsilyl)hex-4-en-3-one
(13a). An oil; IR (neat) 1670 (CvO), 1610 (CvC), 1250,
1
and 845 cm21; H NMR (CDCl3) 20.03 (9H, s, SiMe3),
4-Cyclohexylidene)-5-(trimethylsilyl)pent-1-en-3-one (3).
An oil; IR (neat) 1670 (CvO), 1610 (CvC), 1260, 1030,
1.48±1.59 (6H, m), 1.74 (2H, br s, CH2SiMe3), 2.10 (2H,
m, CvCCH2), 2.11 (3H, d, Jˆ5.5 Hz, Me), 2.22 (2H, m,
CvCCH2), and 6.13±6.23 (2H, m, CHvCH); 13C NMR
(CDCl3) 21.0 (3CH3), 15.8 (CH3), 19.8 (CH2), 26.6
(CH2), 27.6 (CH2), 28.2 (CH2), 31.1 (CH2), 32.4 (CH2),
129.9 (CH), 132.9 (C), 138.1 (C), 141.9 (CH), and 200.5
(CO); MS m/z 250 (M1, 5%), 235 (M12Me, 100), 207 (7),
193 (6), 167 (9), 145 (8), 117 (7), 83 (11), and 73 (62);
HRMS [Found: m/z 250.1801 (M1). Calcd for C15H26OSi:
M, 250.1754].
1
and 805 cm21; H NMR (CDCl3) 20.02 (9H, s, SiMe3),
1.43±1.61 (6H, m), 1.72 (2H, br s, CH2SiMe3), 2.13 (4H,
m, CvCCH2), 5.84 (1H, dd, Jˆ1.8, 10.4 Hz, CvCHH),
6.19 (1H, dd, Jˆ1.8, 17.4 Hz, CvCHH), and 6.41 (1H,
dd, Jˆ10.4, 17.4 Hz, CHvCH2); 13C NMR (CDCl3) 21.0
(3C), 20.3, 26.4, 27.7, 28.0, 30.8, 32.9, 128.9, 129.7, 137.4,
138.5, and 200.9; MS m/z 236 (M1, 20%), 221 (28), 208 (7),
193 (19), 182 (20), and 73 (100); HRMS [Found: m/z
236.1580 (M1). Calcd for C14H24OSi: M, 236.1597].
(E)-2-Cyclohexylidene-1-(trimethylsilyl)hex-4-en-3-one
(13b). An oil; IR (neat) 1655 (CvO), 1620 (CvC), 1445,
4-Cyclopentylidene-5-(trimethylsilyl)pent-1-en-3-one (7).
An oil; IR (neat) 1660 (CvO), 1605 (CvC), 1405, 1250,
1245, and 845 cm21 1H NMR (CDCl3) 20.03 (9H, s,
;
1
and 840 cm21; H NMR (CDCl3) 20.03 (9H, s, SiMe3),
SiMe3), 1.41±1.60 (6H, m), 1.68 (2H, br s, CH2SiMe3),
1.89 (3H, dd, Jˆ1.6, 6.9 Hz, Me), 2.05±2.14 (4H, m,
CvCCH2£2), 6.13 (1H, dq, Jˆ15.5, 1.6 Hz, CHvCHCH3),
and 6.80 (1H, dq, Jˆ15.5, 6.9 Hz, CHvCHCH3); 13C NMR
(CDCl3) -0.9 (3C), 18.3, 20.4, 26.5, 27.6, 28.0, 30.6, 32.7,
130.1, 132.9, 136.9, 144.1, and 201.0; MS m/z 250 (M1,
8%), 235 (M1±Me, 100), 205 (13), 193 (6), 167 (8), 145
(7), and 73 (51); HRMS [Found: m/z 250.1798 (M1). Calcd
for C15H26OSi: M, 250.1754].
1.61±1.70 (4H, m, CH2CH2), 1.80 (2H, br s, CH2SiMe3),
2.28 (2H, m, CvCCH2), 2.44 (2H, m, CvCCH2), 5.69 (1H,
dd, Jˆ1.8, 10.3 Hz, CvCHH), 6.20 (1H, dd, Jˆ1.8,
17.2 Hz, CvCHH), and 6.65 (1H, dd, Jˆ10.3, 17.2 Hz,
CHvCH2); 13C NMR (CDCl3) 20.90 (3C), 21.4, 25.4,
27.5, 33.3, 34.1, 127.5, 131.0, 136.2, 150.0, and 196.1;
MS m/z 222 (M1, 64%), 221 (55), 207 (43), 194 (23), and
71 (100); HRMS [Found: m/z 222.1442 (M1). Calcd for
C13H22OSi: M, 222.1441].
4-Cyclohexylidene-2-methyl-5-(trimethylsilyl)pent-1-en-
3-one (14). An oil; IR (neat) 1665 (CvO), 1630 (CvC),
(E)-4-(3-Methylcyclopentylidene)-5-(trimethylsilyl)pent-
1-en-3-one (10a). An oil; IR (neat) 1665 (CvO), 1605
1
1450, 1250, 860, and 840 cm21; H NMR (CDCl3), 20.04
(CvC), 1405, 1250, and 840 cm21
;
1H NMR (CDCl3;
(9H, s, SiMe3), 1.37±1.57 (6H, m), 1.64 (2H, br s,
CH2SiMe3), 1.86 (3H, t, Jˆ1.1 Hz, Me), 1.94 (2H, m,
CvCCH2), 2.10 (2H, m, CvCCH2), 5.79 (1H, quint,
Jˆ1.4 Hz, CvCHH), and 5.92 (1H, m, CvCHH); 13C
NMR (CDCl3) 20.9 (3C), 16.8, 20.9, 26.5, 27.6, 27.7,
30.2, 32.9, 127.2, 128.7, 136.0, 144.4, and 203.7; MS m/z
250 (M1, 6%), 235 (8), 226 (28), 175 (75), 159 (76), 73
(100), and 58 (83); HRMS [Found: m/z 250.1732 (M1).
Calcd for C15H26OSi: M, 250.1754].
detailed assignment was made by COSY spectrum) -0.04
(9H, s, SiMe3), 0.99 (3H, d, Jˆ6.2 Hz, 30-Me), 1.23 (1H, m,
40-H), 1.70 (1H, br d, Jˆ14 Hz, CHHSiMe3), 1.85 (1H, m,
40-H), 1.86 (1H, br d, Jˆ14 Hz, CHHSiMe3), 1.96 (1H, m,
30-H), 2.01 (1H, m, 20-H), 2.26 (1H, br dt, Jˆ18, 8 Hz,
50-H), 2.39 (1H, br dd, Jˆ8, 18 Hz, 50-H), 2.64 (1H, br
dd, Jˆ5, 15 Hz, 20-H), 5.69 (1H, dd, Jˆ1.8, 10.3 Hz,
CvCHH), 6.19 (1H, dd, Jˆ1.8, 17.2 Hz, CvCHH), and
6.64 (1H, dd, Jˆ10.3, 17.2 Hz, CHˆCH2); 13C NMR
(CDCl3) -0.9 (3C), 19.5, 21.1, 33.0, 33.4, 35.7, 42.6, 127.5,
131.3, 136.2, 149.9, and 196.0; MS m/z 236 (M1, 31%), 221
(M12Me, 49), 181 (29), 91 (41), and 73 (100); HRMS Found:
m/z 236.1559 (M1). Calcd for C14H24OSi: M, 236.1597].
4-Cyclopentylidene-2-methyl-5-(trimethylsilyl)pent-1-en-
3-one (17). An oil; IR (neat) 1645 (CvO), 1630 (CvC),
1250, 860, and 840 cm21; 1H NMR (CDCl3) 20.04 (9H, s,
SiMe3), 1.51±1.66 (4H, m, CH2CH2), 1.72 (2H, quint,
Jˆ1.0 Hz, CH2SiMe3), 1.88 (3H, dd, Jˆ0.8, 1.5 Hz, Me),
2.13±2.24 (4H, m, CvCCH2£2), 5.71 (1H, quint,
Jˆ1.5 Hz, CvCHH), and 5.76 (1H, dq, Jˆ1.5, 0.8 Hz,
CvCHH); 13C NMR (CDCl3) 21.0 (3C), 17.1, 22.7, 25.6,
27.2, 31.8, 33.3, 125.9, 129.4, 144.2, 144.4, and 202.3; MS
m/z 236 (M1, 42%), 221 (47), 205 (100), 195 (52), and 73
(62); HRMS [Found: m/z 236.1588 (M1). Calcd for
C14H24OSi: M, 236.1597].
(Z)-4-(3-Methylcyclopentylidene)-5-(trimethylsilyl)pent-
1-en-3-one (10b). An oil; IR (neat) 1660 (CvO), 1605
;
(CvC), 1400, 1250, 860, and 840 cm21 1H NMR
(CDCl3; detailed assignment was made by COSY spectrum)
-0.04 (9H, s, SiMe3), 1.02 (3H, d, Jˆ6.5 Hz, 30-Me), 1.22
(1H, m, 40-H), 1.71 (1H, br d, Jˆ14 Hz, CHHSiMe3), 1.84
(2H, m, 20-H and 40-H), 1.86 (1H, br d, Jˆ14 Hz,
CHHSiMe3), 2.00 (1H, m, 30-H), 2.38 (1H, br dd, Jˆ8,
17 Hz, 50-H), 2.47 (1H, br dd, Jˆ7, 17 Hz, 20-H), 2.58
(1H, br dd, Jˆ7, 17 Hz, 50-H), 5.69 (1H, dd, Jˆ1.9,
(E)-4-Cyclohexylidene-1-phenyl-5-(trimethylsilyl)pent-1-
en-3-one (19). An oil; IR (neat) 1640 (CvO), 1605 (CvC),

6452
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
1575, 1450, 1250, 985, 840, and 690 cm21
;
1H NMR
1045 cm21
;
1H NMR (CDCl3, Me4Siˆ0.00) 1.41±1.62
(CDCl3) 0.01 (9H, s, SiMe3), 1.46±1.66 (6H, m), 1.79
(2H, br s, CH2SiMe3), 2.19 (4H, m, CvCCH2£2), 6.77
(1H, d, Jˆ16.0 Hz, CHvCHPh), and 7.37±7.56 (6H, m,
Ph and CHvCHPh); 13C NMR (CDCl3) 20.9 (3C), 20.5,
26.5, 27.7, 28.1, 30.8, 32.9, 127.5, 128.3 (2C), 128.9 (2C),
130.3, 130.5, 134.9, 137.9, 143.6, and 200.7; MS m/z 312
(M1, 62%), 283 (62), 269 (58), 213 (88), 168 (85), 133
(100), 117 (99), and 78 (91); HRMS [Found: m/z
312.1902 (M1). Calcd for C20H28OSi: M, 312.1910].
(6H, m), 1.75 (3H, br s, CringvCCH3), 1.80 (3H, quint,
Jˆ1.0 Hz, CH3CHvCCH3), 1.87 (3H, dq, Jˆ7.0, 1.0 Hz,
CH3CHvCCH3), 1.92 (2H, br dd, Jˆ5, 7 Hz, CvCCH2),
2.19 (2H, br dd, Jˆ5, 7 Hz, CvCCH2), and 6.73 (1H, qq,
Jˆ1.2, 7.0 Hz, CvCH); 13C NMR (CDCl3) 10.3, 15.0, 15.9,
26.5, 27.6, 27.7, 29.6, 32.6, 126.3, 137.7, 137.9, 141.5, and
204.4; MS m/z 192 (M1, 39%), 177 (100), 149 (32), 135
(82), 109 (13), and 55 (43); HRMS [Found: m/z 192.1516
(M1). Calcd for C13H20O: M, 192.1515].
4-Cyclohexylidene-2-phenyl-5-(trimethylsilyl)pent-1-en-
3-one (20). An oil; IR (neat) 1665 (CvO), 1445, 1245, 970,
840, and 700 cm21; 1H NMR (CDCl3) 0.03 (9H, s, SiMe3),
1.44±1.64 (6H, m), 1.74 (2H, br s, CH2SiMe3), 2.17 (4H, m,
CvCCH2£2), 6.07 (1H, d, Jˆ1.2 Hz, CvCHH), 6.13 (1H,
d, Jˆ1.2 Hz, CvCHH), and 7.29±7.40 (5H, m, Ph); 13C
NMR (CDCl3) 20.8 (3C), 20.6, 26.5, 27.6, 27.8, 30.8,
32.8, 127.0, 128.1, 128.1 (2C), 128.3 (2C), 129.7, 136.9,
138.5, 149.0, and 202.1; MS m/z 312 (M1, 93%), 256
(94), 242 (88), 228 (93), 205 (93), 171 (90), 143 (90), 98
(99), and 70 (100); HRMS [Found: m/z 312.1938 (M1).
Calcd for C20H28OSi: M, 312.1910].
Nazarov cyclization
Typical procedure. To a stirred solution of dry FeCl3
(69.5 mg, 0.429 mmol) in dry CH2Cl2 (10 cm3) was added
a solution of 3 (40.3 mg, 0.170 mmol) in CH2Cl2 (5 cm3) at
2608C under Ar. The reaction temperature was slowly
elevated to 2158C over a period of 3.5 h with stirring,
and then an aqueous solution of NH4Cl was added. The
mixture was extracted with CH2Cl2 and dried. Evaporation
of the solvent followed by silica gel (5 g) column chromato-
graphy using pentane±Et2O (99:1) as eluent afforded 6
(18.7 mg, 67%).
4-Cyclohexylidene-2-methylpent-1-en-3-one (24). An oil;
IR (neat) 1660 (CvO), 1630 (CvC), 1445, 1325, and
For 10a and 10b, FeCl3 and the substrate were mixed at
2308C, and the mixture was slowly warmed to 08C over a
period of 2.5 h. The stirring was continued at 08C for 3.5 h
followed by work up as described above. To obtain a
rearranged product, the reaction temperature was elevated
from 2308C to r.t. over a period of 7 h followed by stirring
at room temperature as shown in Table 1.
1040 cm21
;
1H NMR (CDCl3, Me4Siˆ0.00) 1.43±1.62
(6H, m), 1.77 (3H, br s, CringvCCH3), 1.90 (3H, br s,
CH2vCCH3), 1.96 (2H, m, CvCCH2), 2.20 (2H, m,
CvCCH2), 5.87 (1H, quint, Jˆ1.5 Hz, CvCHH), and
5.95 (1H, m, CvCHH); 13C NMR (CDCl3) 15.7, 16.6,
26.4, 27.6, 27.7, 29.6, 32.7, 126.1, 127.9, 138.7, 144.3,
and 204.3; MS m/z 178 (M1, 45%), 163 (58), 149 (14),
135 (97), 121 (65), 109 (24), 67 (47), and 41 (100);
HRMS [Found: m/z 178.1389 (M1). Calcd for C12H18O:
M, 178.1358].
8-t-Butyl-1-methylenespiro[4.5]decan-2-one (4a,b). An
oil; UV (pentane) lmaxˆ228 nm (e 6.5£103); IR (neat)
1730 (CvO), 1645 (CvC), 1265, 1100, and 735 cm21
;
1H NMR (CDCl3) 1.00±1.72 (9H, m), 0.86 (9H£1/6, s,
t-Bu of 4b), 0.87 (9H£5/6, s, t-Bu of 4a), 1.69 (2H£1/6, t,
Jˆ7.9 Hz, COCH2CH2 of 4b), 1.83 (2H£5/6, t, Jˆ7.9 Hz,
COCH2CH2 of 4a), 2.32 (2H£5/6, t, Jˆ8.1 Hz, COCH2CH2
of 4a), 2.34 (2H£1/6, t, Jˆ8.1 Hz, COCH2CH2 of 4b), 5.18
(1H£5/6, d, Jˆ0.7 Hz, CvCHH of 4a), 5.46 (1H£1/6, d,
Jˆ1.1 Hz, CvCHH of 4b), 5.98 (1H£5/6, br s, CvCHH of
4a), and 6.02 (1H£1/6, d, Jˆ1.1 Hz, CvCHH of 4b); NOE
was observed between t-Bu (d 0.86) and ole®nic proton (d
5.46) for 4b; 13C NMR (C6D6ˆ128.0) assigned for 4a: 23.3
(2CH2), 27.6 (3CH3), 28.5 (CH2), 32.3 (C), 35.3 (CH2), 37.6
(2CH2), 43.2 (C), 47.6 (CH), 114.8 (CH2), 155.4 (C), and
205.9 (CO); MS m/z 220 (M1, 14%), 205 (4), 177 (5), 164
(25), 149 (11), 135 (22), 123 (23), 110 (74), and 57 (100);
HRMS [Found: m/z 220.1869 (M1). Calcd for C15H24O: M,
220.1828].
4-Cyclohexylidenepent-1-en-3-one (25). An oil; IR (neat)
1660 (CvO), 1605 (CvC), 1450, 1400, 1295, and
1
950 cm21; H NMR (CDCl3, Me4Siˆ0.00) 1.46±1.64 (6H,
m), 1.79 (3H, br s, Me), 2.10 (2H, m, CvCCH2), 2.22 (2H,
m, CvCCH2), 5.93 (1H, dd, Jˆ1.7, 10.3 Hz, CvCHH), 6.19
(1H, dd, Jˆ1.7, 17.3 Hz, CvCHH), and 6.40 (1H, dd,
Jˆ10.3, 17.3 Hz, CHvCH2); 13C NMR (CDCl3) 15.2, 26.4,
27.7, 27.9, 30.1, 32.6, 126.2, 130.1, 137.1, 141.5, and 201.8;
MS m/z 164 (M1, 2%), 149 (3), 136 (3), 121 (12), 107 (4), 91
(4), 77 (4), 67 (7), 55 (15), and 43 (100); HRMS [Found: m/z
164.1171 (M1). Calcd for C11H16O: M, 164.1202].
(Z)-2-Cyclohexylidene-4-methylhex-4-en-3-one (26a). An
oil; IR (neat) 1640 (CvO), 1450, 1375, and 1000 cm21; 1H
NMR (CDCl3, Me4Siˆ0.00) 1.48±1.62 (6H, m), 1.80 (3H,
br s,
C
ringvCCH3), 1.83 (3H, dq, Jˆ7.2, 1.4 Hz,
8-Methyl-1-methylenespiro[4.5]decan-2-one (5a,b). An
oil; UV (pentane) lmaxˆ228 nm (e 2.3£103); IR (neat)
CH3CHvCCH3), 1.87 (3H, quint,
Jˆ1.4 Hz,
1730 (CvO), 1640 (CvC), 1260, 1100, and 805 cm21
;
CH3CHvCCH3), 2.19 (4H, m, CvCCH2£2), and 5.91
(1H, qq, Jˆ1.4, 7.2 Hz, CvCH); 13C NMR (CDCl3) 14.6,
15.3, 20.5, 26.4, 27.3, 27.7, 30.6, 32.0, 129.2, 132.7, 137.3,
142.2, and 204.0; MS m/z 192 (M1, 100%), 178 (23), 149
(60), 109 (30), and 55 (71); HRMS [Found: m/z 192.1492
(M1). Calcd for C13H20O: M, 192.1515].
1H NMR (CDCl3) 0.85±1.70 (9H, m), 0.93 (3H£5/6, d,
Jˆ6.2 Hz, Me of 5a), 0.95 (3H£1/6, d, Jˆ6.6 Hz, Me of
5b), 1.74 (2H£1/6, t, Jˆ8.1 Hz, COCH2CH2 of 5b), 1.83
(2H£5/6, t, Jˆ8.1 Hz, COCH2CH2 of 5a), 2.32 (2H£5/6, t,
Jˆ8.1 Hz, COCH2CH2 of 5a), 2.33 (2H£1/6, t, Jˆ8.1 Hz,
COCH2CH2 of 5b), 5.18 (1H£5/6, d, Jˆ0.7 Hz, CvCHH of
5a), 5.41 (1H£1/6, d, Jˆ0.7 Hz, CvCHH of 5b), 5.98
(1H£5/6, br s, CvCHH of 5a), and 6.00 (1H£1/6, d,
(E)-2-Cyclohexylidene-4-methylhex-4-en-3-one (26b).
An oil; IR (neat) 1640 (CvO), 1445, 1285, 1230, and

C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
6453
Jˆ0.7 Hz, CvCHH of 5b); 13C NMR (C6D6ˆ128.0)
assigned for 5a: 22.6 (CH3), 28.6 (CH2), 31.2 (2CH2),
32.3 (CH), 35.2 (CH2), 37.2 (2CH2), 43.0 (C), 114.8
(CH2), 155.4 (C), and 205.9 (CO); MS m/z 178 (M1,
91%), 163 (7), 150 (23), 136 (54), 121 (100), 107 (50), 93
(57), and 79 (70); HRMS [Found: m/z 178.1346 (M1). Calcd
for C12H18O: M, 178.1358].
37.1, 43.7, 46.2, 115.9, 154.2, and 205.3; MS m/z 178
(M1, 42%), 163 (14), 150 (27), 136 (64), 108 (100), 93
(78), and 79 (63); HRMS [Found: m/z 178.1369 (M1).
Calcd for C12H18O: M, 178.1358].
1,3-Dimethylspiro[4.5]dec-3-en-2-one (16). An oil; IR
(neat) 1705 (CvO), 1635 (CvC), and 1450 cm21 1H
;
NMR (C6D6ˆ7.15) 0.90±1.44 (10H, m), 1.04 (3H, d,
Jˆ7.5 Hz, CHCH3), 1.70 (3H, d, Jˆ1.3 Hz, CvCCH3),
1.84 (1H, q, Jˆ7.5 Hz, CHCH3), and 6.92 (1H, q,
Jˆ1.3 Hz, CvCH); 13C NMR (C6D6ˆ128.0) 10.4, 11.0,
22.9, 23.2, 26.0, 33.8, 37.7, 45.1, 52.5, 138.7, 161.7, and
209.4; MS m/z 178 (M1, 4%), 163 (6), 150 (4), 135 (7), 122
(6), 79 (7), 57 (11), and 43 (100); HRMS [Found: m/z
178.1394 (M1). Calcd for C12H18O: M, 178.1358].
1-Methylenespiro[4.5]decan-2-one (6). An oil; UV (pen-
tane) lmaxˆ226 nm (e 4.8£103); IR (neat) 1730 (CvO),
;
1640 (CvC), 1265, 1100, and 805 cm21 1H NMR
(CDCl3) 1.20±1.72 (10H, m), 1.85 (2H, t, Jˆ7.9 Hz,
COCH2CH2), 2.32 (2H, t, Jˆ7.9 Hz, COCH2CH2), 5.22
(1H, d, Jˆ0.7 Hz, CvCHH), and 5.99 (1H, br s,
CvCHH); 13C NMR (C6D6ˆ128.0) 22.5 (2C), 26.0, 29.4,
35.2, 37.1 (2C), 43.3, 115.1, 155.3, and 205.9; MS m/z 164
(M1, 92%), 149 (12), 136 (21), 122 (100), 108 (35), 93 (55),
and 79 (64); HRMS [Found: m/z 164.1237 (M1). Calcd for
C11H16O: M, 164.1202].
1,3-Dimethylspiro[4.4]non-3-en-2-one (18). An oil; IR
(neat) 1705 (CvO), 1640 (CvC), and 1450 cm21 1H
;
NMR (C6D6ˆ7.15) 1.02 (3H, d, Jˆ7.5 Hz, CHCH3),
1.14±1.47 (8H, m), 1.67 (3H, d, Jˆ1.3 Hz, CvCCH3),
1.95 (1H, q, Jˆ7.5 Hz, CHCH3), and 6.47 (1H, q,
Jˆ1.3 Hz, CvCH); 13C NMR (C6D6ˆ128.0) 10.2 (CH3),
12.6 (CH3), 24.3 (CH2), 24.5 (CH2), 33.0 (CH2), 39.7
(CH2), 50.2 (CH), 53.2 (C), 137.6 (C), 163.0 (CH), and
209.9 (CO); MS m/z 164 (M1, 37%), 149 (M1±Me, 90),
136 (63), 121 (38), 107 (65), 93 (52), and 79 (100); HRMS
[Found: m/z 164.1159 (M1). Calcd for C11H16O: M,
164.1202].
1-Methylenespiro[4.4]nonan-2-one (8). An oil; UV (pen-
tane) lmaxˆ223 nm (e 3.1£103); IR (neat) 1730 (CvO),
1645 (CvC), 1455, 1270, and 1100 cm21 1H NMR
;
(C6D6ˆ7.15) 1.20±1.50 (8H, m), 1.26 (2H, t, Jˆ7.7 Hz,
COCH2CH2), 1.99 (2H, t, Jˆ7.7 Hz, COCH2CH2), 4.79
(1H, d, Jˆ0.7 Hz, CvCHH), and 6.03 (1H, d, Jˆ0.7 Hz,
CvCHH); 13C NMR (C6D6ˆ128.0) 24.7 (2C), 30.2, 33.7,
36.5, 39.6 (2C), 113.8, 153.9, and 205.4; MS m/z 150 (M1,
40%), 135 (6), 122 (12), 108 (86), 93 (37), 79 (41), and 72
(100); HRMS [Found: m/z 150.1047 (M1). Calcd for
C10H14O: M, 150.1045].
1-Methylene-4-phenylspiro[4.5]decan-2-one (21). An oil;
IR (neat) 1725 (CvO), 1635 (CvC), 1450, 760, and
700 cm21
;
1H NMR (CDCl3, Me4Siˆ0.00) 0.80±1.80
6-Methyl-1-methylenespiro[4.4]nonan-2-one (11a,b). The
following data were obtained from 4:1 mixture. An oil; IR
(neat) 1725 (CvO), 1635 (CvC), 1460, and 1095 cm21; 1H
NMR (C6D6ˆ7.15) 0.86 (3H£1/5, d, Jˆ6.6 Hz, Me of 11b),
0.89 (3H£4/5, d, Jˆ6.5 Hz, Me of 11a), 1.27 (2H£4/5, m,
COCH2CH2 of 11a), 1.34 (2H£1/5, m, COCH2CH2 of
11b), 0.96±1.87 (7H, m), 1.99 (2H£4/5, t, Jˆ7.7 Hz,
COCH2CH2 of 11a), 2.00 (2H£1/5, t, Jˆ7.7 Hz,
COCH2CH2 of 11b), 4.78 (1H£1/5, d, Jˆ0.9 Hz,
CvCHH of 11b), 4.85 (1H£4/5, d, Jˆ0.9 Hz, CvCHH
of 11a), 6.02 (1H£1/5, d, Jˆ0.9 Hz, CvCHH of 11b),
and 6.05 (1H£4/5, d, Jˆ0.9 Hz, CvCHH of 11a); NOE
signal was observed at ole®nic proton (d 4.85) for 11a
and methylenic protons (d 1.34) for 11b, respectively, on
irradiation of methyl group (d 0.89 for 11a and 0.86
for 11b); 13C NMR (C6D6ˆ128.0) assigned for 11a: 20.5,
33.8, 33.9, 34.7, 36.3, 40.0, 49.0, 51.4, 113.8, 154.1, and
205.5; assigned for 11b: 14.2, 20.8, 22.7, 35.4, 36.7,
39.5, 48.4, 51.6, 113.5, 155.0, and 205.3; MS m/z 164
(M1, 66%), 122 (100), 107 (33), 96 (46), and 79 (59);
HRMS [Found: m/z 164.1222 (M1). Calcd for C11H16O:
M, 164.1202].
(10H, m), 2.52 (1H, dd, Jˆ3.8, 18.9 Hz, COCHH), 2.87
(1H, dd, Jˆ8.7, 18.9 Hz, COCHH), 3.36 (1H, dd, Jˆ3.8,
8.7 Hz, CHPh), 5.36 (1H, d, Jˆ0.6 Hz, CvCHH), 6.16 (1H,
br s, CvCHH), and 7.04±7.29 (5H, m, Ph); 13C NMR
(CDCl3) 21.7, 22.8, 25.5, 31.6, 38.0, 43.3, 46.9, 48.0,
117.2, 126.6, 128.2 (2C), 128.4 (2C), 141.9, 154.1, and
207.8; MS m/z 240 (M1, 91%), 220 (97), 205 (89), 108
(96), 82 (100), and 55 (97); HRMS [Found: m/z 240.1494
(M1). Calcd for C17H20O: M, 240.1515].
A mixture of 1-methyl-3-phenylspiro[4.5]dec-3-en-2-one
(22) and 1-methylene-3-phenylspiro[4.5]dec-2-en-2-ol
(23). An oil; IR (neat) 3240 (OH of 23), 1700 (CvO of
1
22), 1645 (CvC), 1450, and 695 cm21; H NMR (CDCl3)
1.17 (3H£2/3, d, Jˆ7.5 Hz, CH3 of 22), 1.23±1.82 (10H£2/3
for 22 plus 12H£1/3(for 23, m), 2.28 (1H£2/3, q, Jˆ7.5 Hz,
CHCH3 of 22), 5.46 (1H£1/3, br s, CvCHH of 23), 6.15
(1H£1/3, br s, CvCHH of 23), and 7.28±7.96 (5H plus
1H£2/3, m, Ph and CHvC of 22); 13C NMR (CDCl3)
assigned for 22: 10.9, 22.8, 23.1, 25.8, 33.8, 37.5, 45.1,
53.9, 127.1 (2C), 128.3, 128.4 (2C), 131.8, 139.8, 163.7,
and 209.1; assigned for 23: 22.9 (2C), 25.7, 29.7, 36.5
(2C), 44.9, 115.8, 127.2 (2C), 128.4 (2C), 128.6, 141.8,
152.9, 159.3, and 194.5; MS m/z 240 (M1, 92%), 197
(100), 184 (96), and 141 (88); HRMS [Found: m/z
240.1508 (M1). Calcd for C17H20O: M, 240.1515].
4-Methyl-1-methylenespiro[4.5]decan-2-one (15). An oil;
IR (neat) 1725 (CvO), 1635 (CvC), 1450, and 1150 cm21
;
1H NMR (C6D6ˆ7.15) 0.56 (3H, d, Jˆ7.0 Hz, Me), 0.84±
1.40 (10H, m), 1.74 (1H, dd, Jˆ2.7, 18.0 Hz, COCHH),
1.84 (1H, br d quint, Jˆ2.5, 7 Hz, CHMe), 2.25 (1H, dd,
Jˆ6.7, 18.0 Hz, COCHH), 4.90 (1H, d, Jˆ0.9 Hz,
CvCHH), and 6.14 (1H, d, Jˆ0.9 Hz, CvCHH); 13C
NMR (C6D6ˆ128.0) 16.3, 22.2, 22.8, 26.0, 30.9, 33.1,
1,3,4-Trimethylspiro[4.5]dec-3-en-2-one (27). An oil; IR
;
(neat) 1700 (CvO), 1650 (CvC), 1450, and 1385 cm21
1H NMR (CDCl3, Me4Siˆ0.00) 1.02±1.76 (10H, m),
1.17 (3H, d, Jˆ7.4 Hz, CHCH3), 1.66 (3H, q, Jˆ0.7 Hz,

6454
C. Kuroda et al. / Tetrahedron 56 (2000) 6441±6455
CH3CvC(CH3)CO),
1.92
(3H,
q,
Jˆ0.7 Hz,
Acknowledgements
CH3CvC(CH3)CO), and 2.28 (1H, q, Jˆ7.4 Hz, CHCH3);
13C NMR (CDCl3) 8.2, 12.6, 14.8, 23.1, 23.9, 25.2, 28.5,
38.0, 48.3, 49.3, 132.7, 176.3, and 212.2; MS m/z 192 (M1,
77%), 177 (40), 149 (72), 136 (100), 121 (28), and 93 (24);
HRMS [Found: m/z 192.1477 (M1). Calcd for C13H20O: M,
192.1515].
We must thank Prof. K.-T. Kang of Pusan National
University for giving us experimental details on the Nazarov
cyclization reaction and helpful suggestions. Thanks are
also due to Prof. M. M. Ito and Dr T. Niitsu of Soka
University, and Prof. T. Akiyama of Gakushuin University
for the measurement of mass spectra and valuable
discussions.
Rearrangement
Typical procedure. Compound 8 (11.1 mg, 0.0738 mmol)
was treated with FeCl3 (30.5 mg) as described for the
Nazarov cyclization, except that the reaction temperature
was elevated to room temperature for 19 h. The crude
product was chromatographed on silica gel (1 g) using
pentane±Et2O (98:2) as eluent to yield 9 (6.7 mg, 60%).
References
1. For reviews: (a) Hosomi, A. Acc. Chem. Res. 1988, 21, 200±
206. (b) Langkopf, E.; Schinzer, D. Chem. Rev. 1995, 95, 1375±
1408. (c) Fleming, I.; Barbero, A.; Walter, D. Chem. Rev. 1997, 97,
2063±2192. (d) Majetich, G. In Organic Synthesis: Theory and
Application; Hudlicky, T., Ed.; JAI Press: Greenwich, 1989; Vol.
1, pp 173±240. (e) Santelli, M.; Pons, J.-M. Lewis Acids and
Selectivity in Organic Synthesis; CRC Press: Boca Raton, 1996.
2. For review regarding synthesis of various carbocycles: (a) Ho,
T.-L. Carbocycle Construction in Terpene Synthesis; VCH: New
York, 1988. (b) Thebtaranonth, C.; Thebtaranonth, Y. Cyclization
Reactions; CRC Press: Boca Raton, 1994. (c) Boden, C. D. J.;
Pattenden, G. Contemp. Org. Synth. 1994, 1, 433±455.
6-Methylbicyclo[4.3.0]non-8-en-7-one (9). An oil; UV
(pentane) lmaxˆ217 nm (e 4.4£103); IR (neat) 1715
(CvO), 1590 (CvC), 1465, 1265, 1075, and 810 cm21
;
1H NMR (C6D6ˆ7.15) 0.98 (3H, s, Me), 0.96±1.40 (7H,
m), 1.61 (1H, br ddd, Jˆ6, 7, 14 Hz, 5-H), 2.06 (1H, ddt-
like, Jˆ5, 6, 2.5 Hz, 1-H), 5.91 (1H, dd, Jˆ2.0, 5.7 Hz,
COCHvCH), and 6.73 (1H, dd, Jˆ2.6, 5.7 Hz,
COCHvCH); NOE was observed between methyl group
(d 0.98) and methine proton (d 2.06); 13C NMR
(C6D6ˆ128.0) 19.5 (CH2), 19.8 (CH2), 23.2 (CH3), 25.6
(CH2), 30.9 (CH2), 46.3 (C), 48.8 (CH), 131.8 (CH), 164.8
(CH), and 212.8 (CO); MS m/z 150 (M1, 53%), 135
(M12Me, 100), 121 (26), 107 (26), 93 (41), and 79 (59);
HRMS [Found: m/z 150.1045 (M1). Calcd for C10H14O: M,
150.1045].
3. Kuroda, C. Recent Res. Develop. Pure Appl. Chem. 1998, 2,
189±198.
4. For examples: (a) Kuroda, C.; Shimizu, S.; Satoh, J. Y. J. Chem.
Soc., Perkin Trans. 1 1990, 519±524. (b) Kuroda, C.; Inoue, S.;
Takemura, R.; Satoh, J. Y. J. Chem. Soc., Perkin Trans. 1 1994,
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5. Kuroda, C.; Nogami, H.; Ohnishi, Y.; Kimura, Y.; Satoh, J. Y.
Tetrahedron 1997, 53, 839±858.
3(or 4),6-Dimethylbicyclo[4.3.0]non-8-en-7-one (12a±e).
An oil; IR (neat) 1710 (CvO), 1585 (CvC), 1460, and
6. Nishitani and co-workers also developed similar chemistry.
For example: Nishitani, K.; Nakamura, Y.; Orii, R.; Arai, C.;
Yamakawa, K. Chem. Pharm. Bull. 1993, 41, 822±831.
7. For examples: (a) Harmata, M. Recent Res. Develop. Org.
Chem. 1997, 1, 523±535. (b) Lee, T. V.; Boucher, R. J.; Porter,
J. R.; Taylor, D. A. Tetrahedron 1988, 44, 4233±4242.
1
805 cm21; H NMR (C6D6ˆ7.15) assigned for 12a: 0.68
(3H, d, Jˆ6.1 Hz, Me), 0.69±0.78 (1H, br, 4b-H), 1.03
(3H, s, Me), 0.96±1.05 (2H, m, 2-H and 3-H), 1.19±1.32
(2H, m, 2-H and 4a-H), 1.32 (1H, ddd, Jˆ4.0, 6.6, 13.6 Hz,
5b-H), 1.47 (1H, ddd, Jˆ4.4, 10.0, 13.6 Hz, 5a-H), 2.18
(1H, dq-like, Jˆ6, 2.5 Hz, 1-H), 5.90 (1H, dd, Jˆ2.5,
5.7 Hz, 8-H), and 6.70 (1H, dd, Jˆ2.2, 5.7 Hz, 9-H);
NOESY signals were observed between d 1.03±0.74,
1.03±0.68, 1.03±2.18, and 0.68±2.18; assigned for 12b:
0.65 (3H, d, Jˆ6.2 Hz, Me), 1.08 (4H, s, Me), 2.08
(1H, m, 1-H), 5.88 (1H, dd, Jˆ2.5, 5.9 Hz, 8-H), and
6.65 (1H, dd, Jˆ2.0, 5.9 Hz, 9-H); assigned for 12c:
0.68 (3H, d, Jˆ6.8 Hz, Me), 0.95 (3H, s, Me), 1.95
(1H, m, 1-H), 5.84 (1H, dd, Jˆ1.5, 5.8 Hz, 8-H), and
6.85 (1H, dd, Jˆ3.0, 5.8 Hz, 9-H); assigned for 12d:
0.73 (3H, d, Jˆ6.6 Hz, Me), 1.12 (3H, s, Me), 1.81
(1H, m, 1-H), 5.81 (1H, br d, Jˆ5.5 Hz, 8-H) and
6.96 (1H, br d, Jˆ5.5 Hz, 9-H); assigned for 12e:
0.84 (3H, d, Jˆ6.9 Hz, Me), 1.09 (3H, s, Me), 1.84
(1H, m, 1-H), 5.80 (1H, br d, Jˆ5.5 Hz, 8-H) and
6.95 (1H, br d, Jˆ5.5 Hz, 9-H); 13C NMR
(C6D6ˆ128.0) assigned for 12a: 21.0, 22.6, 26.8, 29.3,
32.0, 34.0, 46.2, 48.7, 131.6, 164.5, and 212.6; MS m/z
164 (M1, 46%), 149 (M12Me, 100), 121 (27), 107
(28), 91 (34), 79 (38), and 57 (54); HRMS
[Found: m/z 164.1228 (M1). Calcd for C11H16O: M,
164, 1202].
8. For examples: (a) Knapp, S.; O'Connor, U.; Mobilio, D.
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(b) Kuroda, C.; Murase, A.; Suzuki, H.; Endo, T.; Anzai, S. Bull.
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