Self-cyclization of (E)-2-(trimethylsilylmethyl)pentadienol derivative. Synthesis of bicyclo[4.3.0]nonane ring systems

Article abstract of DOI:10.1016/j.tet.2005.09.146

Utility and limitation of the title reaction was studied. When (E)-3-(4-t-butyl- and 4-phenylcyclohex-1-en-1-yl)-2-(trimethylsilylmethyl)prop- 2-en-1-ols were treated with Ms₂O or MsCl, 3-t-butyl- and 3-phenyl-8-methylbicyclo[4.3.0]nona-1(6),7-

Full text of DOI:10.1016/j.tet.2005.09.146

Tetrahedron 62 (2006) 726–730
Self-cyclization of (E)-2-(trimethylsilylmethyl)pentadienol
derivative. Synthesis of bicyclo[4.3.0]nonane ring systems
a
a
b
Chiaki Kuroda,a, Masatoshi Okada, Shinya Shinozaki and Hideyuki Suzuki
*
aDepartment of Chemistry, Rikkyo University, Nishi-Ikebukuro, Toshima-ku, Tokyo 171-8501, Japan
bResearch Foundation of Itsuu Laboratory, Tamagawa, Setagaya-ku, Tokyo 158-0094, Japan
Received 28 July 2005; accepted 30 September 2005
Available online 3 November 2005
Abstract—Utility and limitation of the title reaction was studied. When (E)-3-(4-t-butyl- and 4-phenylcyclohex-1-en-1-yl)-2-
(trimethylsilylmethyl)prop-2-en-1-ols were treated with Ms2O or MsCl, 3-t-butyl- and 3-phenyl-8-methylbicyclo[4.3.0]nona-1(6),7-dienes
were obtained, respectively. The corresponding (Z)-isomer afforded a complex mixture, among which an elimination product was detected.
(E)-4-(4-t-Butylcyclohexylidene)-2-(trimethylsilylmethyl)but-2-en-1-ol afforded only elimination product.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
review articles.8 The related [3C4] cycloaddition reaction
(homo-Diels–Alder type of reaction) utilizing this unit as
the dienophile has also been established.9 We recently
reported a five-carbon ring expansion reaction by replacing
a,b-Unsaturated carbonyl compounds substituted by tri-
methylsilylmethyl group at the a-position are unique
building blocks in organic synthesis since the b-carbon
reacts as an allylsilane1 but not as an unsaturated carbonyl.
Therefore, this moiety acts as a carbon 1,3-dipole based on
the nucleophilicity of the b-carbon and the electrophilicity
of the carbonyl carbon.2 This enables to synthesize odd-
membered ring compounds3 via a reaction with the
appropriate double-bond compound (Scheme 1, type a).
We previously prepared several five-membered ring
compounds such as g-lactones4 or cyclopentanes5 via this
type of reaction.6 Further conjugated compounds, that is,
a,b,g,d-unsaturated carbonyl compounds having a-tri-
methylsilylmethyl group cyclize themselves to a five-
membered ring since the d-carbon is nucleophilic and
reacts with carbonyl carbon (Scheme 1, type b). As an
example of this type of reaction, we recently described
synthesis of bicyclo[4.3.0]nonane and spiro[4.5]decane
carbon skeletons (vide infra).7
type a
SiMe3
OH
O
O
Y
Y
Y
X
X
Z
Z
Z
(if X = leaving group)
type b
SiMe3
O
OH
X
O
X
(if X = leaving group)
type c
SiMe3
SiMe3
OH
On the other hand, b-(hydroxymethyl)allylsilane also acts as
a carbon-1,3-dipole after conversion of the hydroxy group
into an appropriate leaving group. The expected product is a
five-membered ring after reaction with a double-bond
compound (Scheme 1, type c). This type of reaction was
developed by Trost’s group and is well documented in
L
Y
Z
Y
Z
type d
SiMe3
OH
SiMe3
L
Keywords: Bicyclo[4.3.0]nonane; Allylsilane; Pentadienol; Cyclization.
*
Corresponding author. Tel.: C81 3 3985 2396; fax: C81 3 3985 2396;
e-mail: chkkuroda@grp.rikkyo.ne.jp
Scheme 1.
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.09.146

C. Kuroda et al. / Tetrahedron 62 (2006) 726–730
727
the C]C double bond of the Cope rearrangement with a
b-(hydroxymethyl)allylsilane unit (homo-Cope type of
reaction).10
the cyclization of the 3-cyclohexenyl-2-(trimethylsilyl-
methyl)prop-2-en-1-ol derivative expecting that the cycliza-
tion would occur faster than elimination. Since the expected
cyclization product is a hydrocarbon, we chose the t-butyl-
or phenyl-substituted compounds 8 and 9 as the substrates in
order to reduce handling problem due to volatility.
Compounds 87a and 9 were synthesized from 4-t-butyl-
cyclohex-1-enecarbaldehyde (10) and 4-phenylcyclohex-1-
enecarbaldehyde (11), respectively, via the (E)-selective
Horner–Wadsworth–Emmons (HWE) reactions11 followed
by DIBAL-H reduction of the ester 12 and 13 (Scheme 3).
Compound 11 was prepared from 4-phenylcyclohex-2-en-
1-one12 (see Section 3), which was prepared from
4-phenylcyclohexanone by a standard method.
Further conjugation to b-(hydroxymethyl)allylsilane
provides the fourth type of substrate (Scheme 1, type d).
Although this type of reaction is an analogue of the ‘type b’,
a problem is expected. Namely, it is for a simple elimination
to occur as a competitive reaction, giving a triene if the
double bond has some substituents, while this type of
elimination reaction is not expected for the ‘type b’ reaction.
The aim of the present study is to clarify the utility and the
limitation of this type of reaction.
We planned to study the cyclization of ‘type d’ on the basis
of our previous study of the ‘type b’ reaction,7a the outline
of which is shown in Scheme 2. In these reactions, the
geometry of the cyclization precursor was an important
factor for the synthesis of bicyclo[4.3.0]nonane. Namely,
(E)-precursor 1 cyclized to give the expected product 2 in
good yield, while (Z)-precursor 3 afforded only a complex
mixture. In contrast, in the synthesis of the spiro[4.5]decane
carbon framework, both (E)- (4) and (Z)-dienes (5)
ultimately afforded the same compound 6, which is
the isomerization product of 7. Here we report that
bicyclo[4.3.0]nonane can be synthesized from (E)-2-
(trimethylsilylmethyl)pentadienol, as in the case of penta-
dienal, however, spiro[4.5]decane was not obtained.
CHO
10 R=tBu
11 R=Ph
R
i
ii
CO2Et
SiMe3
SiMe3
CO2Et
R
Ph
12 R=tBu
13 R=Ph
18
iii
iii
SiMe3
CHO
SiMe3
OH
OH
H
OH
R
Ph
SiMe3
1
2
8 R=tBu
9 R=Ph
17
CHO
FeCl3
Scheme 3. Reagents and conditions: (i) (PhO)2P(O)CH(CO2Et)CH2SiMe3,
NaH, THF, rt; (ii) (EtO)2P(O)CH(CO2Et)CH2SiMe3, NaH, THF, rt;
(iii) DIBAL-H, CH2CH2, K60 8C.
various products
SiMe3
3
The ‘type d self-cyclization reaction’ was then studied.
Firstly, following our previous report on the five-carbon ring
expansion reaction,10 8 was treated with Tf2O in CH2Cl2 at
K60 8C in the presence of 2,6-lutidine, however, only a
complex product mixture was obtained. Some other
bases such as Na2CO3, LDA, and BuLi were used instead
of 2,6-lutidine but no cyclization product was obtained.
Conversion of the hydroxy group into halogen was also tried
using halogenation reagents such as PPh3/CBr4,13 but
without success.
R1
FeCl3
R2
OH
R
R
4 R1=CHO, R2=CH2SiMe3
5 R1=CH2SiMe3 R2=CHO
7
Then, 8 was converted to its mesylate, which is a less reactive
leaving group than triflate. When 8 was treated with Ms2O in
CH2Cl2 and pyridine at room temperature, the reaction
proceeded within 10 min. The product was not the mesylate
but a bicyclic hydrocarbon formed by the ‘type d’ cyclization
reaction (85% yield) (Scheme 4). The product was found not
to be the originally expected compound 14 (RZt-Bu), but 15,
as characterized from the NMR spectra. Namely, although
four olefinic carbons were observed in the 13C NMR, the
terminal olefin protons expected for 14 were not found in the
1H NMR, but instead of them, only one alkene proton was
O
R
6
Scheme 2.
2. Results and discussion
Following the fact that (E)-2-(trimethylsilylmethyl)penta-
dienal 1 cyclized immediately,7a we first studied

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C. Kuroda et al. / Tetrahedron 62 (2006) 726–730
OH
SiMe3
i
8, 9
R
t-Bu
14
i
20
t-Bu
15 R = t-Bu
16 R = Ph
21
R
Scheme 6. Reagents and conditions: (i) Ms2O, pyridine, CH2Cl2, 0 8C.
Scheme 4. Reagents and conditions: (i) Ms2O (for 8) or MsCl (for 9),
pyridine, CH2Cl2, 0 8C.
pentadienol are close to each other for 8 (and 9) but far for
20. For 8, steric congestion of both s-cis (Scheme 7,
conformer 8-c) and s-trans (8-t) conformers are almost
equal, while s-cis conformer (20-c) is highly congested and
only s-trans conformer (20-t) can be considered for 20.
Also, mesylation is hindered for 20-c by both the
trimethylsilyl group and cyclohexane ring.
found at d 5.90 (br s) together with a pair of methylene
protons (d 2.70 and 2.79) and a methyl group. It is easily
expected that 15 is the isomerization product of 14.
The same reaction was also carried out using 9 as the
substrate. The expected product 16 was obtained in only
28% yield via an analogous Ms2O treatment as above.
However, when MsCl was used as the reagent, 16 was
afforded in 53% yield, although a longer reaction time
(17 h) was required.
SiMe3
15
t-Bu
OH
8-c
Since the geometry of the allylsilane is considered to be an
important factor,7a the reaction of the (Z)-precursor was also
studied using 17 as the substrate, which was prepared via a
(Z)-selective HWE reaction (11 to 18)14 followed by
DIBAL-H reduction (Scheme 3). When 17 was treated
with MsCl or Ms2O in pyridine/CH2Cl2, only a complex
mixture was afforded among which the presence of triene
OH SiMe3
1
19 was detected from H NMR spectrum of the reaction
mixture (Scheme 5). The geometry of the double-bond
in 19 was not determined. Since C-1 and C-5 of the
penta-2,4-dien-1-ol unit in 17 are too distant to cyclize, the
result indicates that the Z to E isomerization did not occur,
while such an isomerization process occurred partly for the
corresponding aldehyde 3.7
t-Bu
8-t
cyclization
product(s)
t-Bu
H
OH SiMe3
i
20-c
17
Ph
19
OH
SiMe3
Scheme 5. Reagents and conditions: (i) MsCl, pyridine, CH2Cl2, 0 8C.
21
Cyclization of 4-cyclohexylidene-2-(trimethylsilyl-
methyl)but-2-en-1-ol derivative to the spiro[4.5]decane
type of compound was also studied. The substrate 20 was
synthesized in accordance with the previously reported
procedure.7 When this compound was treated with Ms2O
and pyridine in CH2Cl2, triene 21 was afforded in 77% yield
(Scheme 6), together with a small amount of its (Z)-isomer.
The (E)-geometry of 21 was determined from the J-value
(16.0 Hz) of the olefinic protons. Both compounds 21 and
19 are considered to be the products of simple elimination of
mesylate followed by protodesilylation.
t-Bu
20-t
Scheme 7.
In conclusion, the utility and limitation of the self-
cyclization reaction of 2-(trimethylsilylmethyl)pentadienol
in the synthesis of five-memberd ring was revealed.
Cyclization of 4,5-disubstituted (E)-2-(trimethylsilyl-
methyl)pentadienol occurred predominantly over the
elimination reaction, and was shown to be useful in the
synthesis of bicyclo[4.3.0]nonane compounds. In contrast,
the elimination reaction giving triene occurred from both
4,5-disubstituted (Z)-2-(trimethylsilylmethyl)pentadienol
The difference in results between 8 and 20 indicates that the
substitution pattern of the 2-(trimethylsilylmethyl)penta-
dienol is an important factor. Namely, C-1 and C-5 of

C. Kuroda et al. / Tetrahedron 62 (2006) 726–730
729
and 5,5-disubstituted (E)-2-(trimethylsilylmethyl)penta-
3.3.1.
2-(trimethylsilylmethyl)prop-2-enoate (13). An oil; IR
(E)-Ethyl
3-(4-phenylcyclohex-1-en-1-yl)-
dienol. This suggests that both the geometry of the
double-bond and the position of the substituents are
important factors for the self-cyclization reaction.
(neat) 2952, 1720, 1248, 1217, and 852 cmK1; H NMR
1
(CDCl3) dZ0.10 (9H, s, SiMe3), 1.33 (3H, t, JZ7.1 Hz,
OCH2CH3), 1.71–2.48 (8H, m), 2.77–2.87 (1H, m), 4.21 (AB,
each q, JZ7.1 Hz, OCH2CH3), 5.76 (1H, br, C]CHCring),
5.93 (1H, br s, CH]CCO2Et), and 7.18–7.37 (5H, m, Ph); 13
C
3. Experimental
3.1. General procedure
NMR (CDCl3) dZK1.67 (3C), 14.01, 25.63, 27.44, 29.72,
33.98, 39.59, 60.21, 125.91, 126.64 (2C), 127.74, 128.23
(2C), 129.20, 132.87, 134.93, 146.64, and 170.56; MS m/z 342
(MC, 4%), 297 (3), 223 (11), 195 (6), 117 (14), 91 (31), and 73
(100); HRMS [Found: m/z 342.2064 (MC). Calcd for
C21H30O2Si: 342.2015].
IR spectra were recorded on a Jasco FT/IR-230 spectro-
1
meter. Both H and 13C NMR spectra were measured on a
Jeol GSX-400 (400 MHz for 1H; 100 MHz for 13C)
spectrometer. Chemical shifts were reported on the d scale
(ppm) with solvent (CHCl3Z7.26) as an internal standard,
unless otherwise noted. The signal of the solvent (CDCl3Z
77.0) was used as a standard for 13C NMR spectra. Both
low-resolution mass spectra (MS) and high-resolution mass
spectra (HRMS) were obtained on a Jeol SX-102A,
CMATE II, or Shimadzu GCMS-QP5050 mass spectro-
meter with the EI method. Analytical TLC was done on
precoated TLC plates (Kieselgel 60 F254, layer thickness
0.2 mm). Wakogel C-200 or florisil (100–200 mesh) was
used for column chromatography. Anhydrous Na2SO4 or
MgSO4 was used for drying the extracted organic layers. For
dry solvent, THF was distilled from LiAlH4, and CH2Cl2
was distilled from CaH2. All new compounds were
3.4. (Z)-Selective HWE reaction
See our previous paper for the procedure.7a Compound 18
(90%) was prepared from 11 but was not characterized
at this stage and was subjected to the next reduction step
(18 to 17) without purification.
3.5. Reduction
See our previous paper for the procedure and the spectral
data of 8. By the same procedure, 13 and 18 afforded 9
(100%) and 17 (90%), respectively.
1
determined to be O95% pure by H and 13C NMR, unless
3.5.1. (E)-3-(4-Phenylcyclohex-1-en-1-yl)-2-(trimethyl-
silylmethyl)prop-2-en-1-ol (9). An oil; IR (neat) 3338,
2927, 1246, 1018, 852, 756, and 698 cmK1; 1H NMR (CDCl3)
dZ0.07 (9H, s, SiMe3), 1.65–2.45 (9H, m), 2.75–2.84 (1H,
m), 4.20 (1H, d, JZ12.0 Hz, CHHOH), 4.29 (1H, d, JZ
12.0 Hz, CHHOH), 5.56 (1H, br, C]CHCring), 5.60 (1H, br s,
CH]CCH2OH), and 7.18–7.34 (5H, m, Ph); 13C NMR
(CDCl3) dZK1.31 (3C), 24.93, 29.84, 30.02, 33.74, 39.71,
62.34, 124.85, 125.93, 126.73 (2C), 128.13, 128.27 (2C),
134.72, 137.47, and 146.82; MS m/z 300 (MC, 8%), 271 (55),
210 (7), 195 (7), 181 (8), 167 (7), 155 (7), 117 (17), 91 (48),
and 73 (100); HRMS [Found: m/z 300.1922 (MC). Calcd for
C19H28OSi: 300.1910].
otherwise noted.
3.2. Preparation of the substrates
3.2.1. 4-Phenylcyclohex-1-enecarbaldehyde (11). To a
stirred solution of LDA, prepared from iPr2NH (0.90 cm3,
5.93 mmol) and BuLi (2.0 cm3, 3.08 mmol, 1.54 M solution
in hexane) in dry THF (3 cm3) was added a solution of
Ph2P(O)CH2OMe (730 mg, 2.11 mmol) in THF (13 cm3) at
K60 8C under Ar. A solution of 4-phenylcyclohex-2-en-
1-one (255 mg, 1.48 mmol) in THF (6 cm3) was added, and
the mixture was stirred with slow warming to room
temperature. After confirming the reaction on TLC, an
aqueous solution of HCl (2 M) was added, and the mixture
was heated to 80–90 8C for 20 h. This was cooled to room
temperature again, NaHCO3 aq. was added, and the product
was extracted with Et2O and dried. Evaporation of the
solvent followed by silica gel (15 g) column chromato-
graphy using hexane–Et2O (9/1) as eluent yielded 11
(168.9 mg, 61%) as an oil; IR (neat) 2927, 1682, 1643,
1163, 758, and 700 cmK1; 1H NMR (CDCl3, Me4SiZ0.00)
dZ1.66–1.78 (1H, m), 2.00–2.08 (1H, m), 2.16–2.28 (1H,
m), 2.38–2.55 (2H, m), 2.60–2.70 (1H, m), 2.80–2.90 (1H,
m), 6.85–6.89 (1H, m, C]CH), 7.19–7.34 (5H, m, Ph), and
9.48 (1H, s, CHO); 13C NMR (CDCl3) dZ21.79, 28.60,
34.29, 39.68, 126.38, 126.67 (2C), 128.49 (2C), 141.24,
145.45, 150.35, and 193.76; MS m/z 186 (MC, 11%), 115
(6), 104 (100), 95 (28), 78 (14), and 51 (13); HRMS [Found:
m/z 186.1074 (MC). Calcd for C13H14O: 186.1045].
3.5.2. (Z)-3-(4-Phenylcyclohex-1-en-1-yl)-2-(trimethyl-
silylmethyl)prop-2-en-1-ol (17). An oil; IR (neat) 3390,
1726, 1452, and 852 cmK1; 1H NMR (CDCl3) dZ0.07 (9H,
s, SiMe3), 1.73–2.48 (9H, m), 2.75–2.84 (1H, m), 4.20 (2H,
s, CH2OH), 5.73 (1H, br, C]CHCring), 5.78 (1H, br s,
CH]CCH2OH), and 7.18–7.34 (5H, m, Ph); 13C NMR
(CDCl3) dZK0.56 (3C), 19.84, 29.88, 30.02, 33.79, 39.72,
69.34, 124.69, 125.53, 125.98, 126.84 (2C), 128.34 (2C),
135.01, 137.28, and 146.95; MS m/z 300 (MC, 2%), 271 (1),
210 (13), 195 (10), 181 (10), 167 (10), 155 (9), 117 (30), 106
(42), 91 (74), and 73 (100); HRMS [Found: m/z 300.1927
(MC). Calcd for C19H28OSi: 300.1910].
3.6. Cyclization reaction
In a 10 cm3 round bottomed flask, a solution of 8 (27.4 mg,
0.094 mmol) in dry CH2Cl2 (3 cm3, freshly distilled from
CaH2) was prepared, and to this solution was added
successively pyridine (0.055 cm3) and methanesulfonic
anhydride (70.8 mg, 0.40 mmol) at 0 8C with stirring.
CaCl2 drying tube was attached, and the stirring was
continued for 10 min. Water was added, and the product was
3.3. (E)-Selective HWE reaction
See our previous paper for the procedure and spectral data of
12.7a By the same procedure, 13 (29.5 mg, 77%) was
synthesized from 11 (21.0 mg).

730
C. Kuroda et al. / Tetrahedron 62 (2006) 726–730
extracted with Et2O followed by drying and evaporation.
The resultant residue was chromatographed on florisil (1 g)
using pentane as eluent to afford 15 (15.1 mg, 85%).
91 (44), 57 (100), and 41 (93); HRMS [Found: m/z 204.1870
(MC). Calcd for C15H24: 204.1878].
Acknowledgements
Similarly, 9 (6.7 mg, 0.022 mmol) afforded 16 (2.5 mg,
53%) by treatment with methanesulfonic chloride
(0.007 cm3) instead of methanesulfonic anhydride in
pyridine (0.015 cm3) and CH2Cl2 (3 cm3).
The authors wish to thank Professor E. Horn of Rikkyo
University for help in the writing of this article. The
financial support was partly obtained from Frontier Project
of Rikkyo University.
3.6.1. 3-t-Butyl-8-methylbicyclo[4.3.0]nona-1(6),7-diene
(15). An oil; IR (neat) 2924, 1645, 1468, 1365, 1265, and
741 cmK1 1H NMR (CDCl3) dZ0.90 (9H, s, t-Bu),
;
1.17–1.40 (2H, m), 1.85–2.34 (5H, m), 2.01 (3H, s, Me),
2.70 (1H, dd, JZ3.5, 22 Hz), 2.79 (1H, br d, JZ22 Hz), and
5.90 (1H, br s); 13C NMR (CDCl3) dZ24.6, 25.5, 26.8, 27.4
(3C), 29.7, 32.4, 45.3, 46.9, 128.9, 137.0, 138.0, and 141.9;
MS m/z 190 (MC, 21%), 175 (3), 133 (34), 106 (100), 91
(84), and 41 (44); HRMS [Found: m/z 190.1691 (MC).
Calcd for C14H22: 190.1722].
References and notes
1. For review on the reaction of allylsilane, (a) Fleming, I.;
Barbero, A.; Walter, D. Chem. Rev. 1997, 97, 2063–2192. (b)
Yamamoto, Y.; Asao, N. Chem. Rev. 1993, 93, 2207–2293.
(c) Hosomi, A. Acc. Chem. Res. 1988, 21, 200–206.
2. (a) Kuroda, C.; Suzuki, H. Curr. Org. Chem. 2003, 7, 115–131.
(b) Kuroda, C. Recent Res. Devel. Pure Appl. Chem. 1998, 2,
189–198.
3.6.2. 8-Methyl-3-phenylbicyclo[4.3.0]nona-1(6),7-dien
(16). An oil; IR (neat) 2925, 1452, 1377, 750, and
1
698 cmK1; H NMR (CDCl3) dZ1.77–2.06 (2H, m), 2.04
3. For review on the synthesis of carbocycles, see, (a) Ho, T.-L.
Carbocycle Construction in Terpene Synthesis; VCH:
New York, 1988. (b) Thebtaranonth, C.; Thebtaranonth, Y.
Cyclization Reactions; CRC: Boca Raton, 1994.
(3H, s, Me), 2.35–2.60 (4H, m), 2.77 (1H, br d, JZ22.7 Hz,
CHH in cyclopentadiene), 2.84 (1H, br d, JZ22.7 Hz, CHH
in cyclopentadiene), 2.84–2.92 (1H, m), 5.95 (1H, s, CH]C),
and 7.18–7.34 (5H, m, Ph); 13C NMR (CDCl3) dZ16.18,
24.86, 30.47, 33.63, 41.27, 46.64, 125.94, 126.95 (2C),
128.32 (2C), 128.84, 136.12, 137.98, 142.20, and 147.31; MS
m/z 210 (MC, 22%), 106 (100), and 91 (90); HRMS [Found:
m/z 210.1375 (MC). Calcd for C16H18: 210.1409].
4. For examples, (a) Kuroda, C.; Ito, K. Bull. Chem. Soc. Jpn.
1996, 69, 2297–2303. (b) Kuroda, C.; Kobayashi, K.; Koito,
A.; Anzai, S. Bull. Chem. Soc. Jpn. 2001, 74, 1947–1961. (c)
Kuroda, C.; Inoue, S.; Takemura, R.; Satoh, J. Y. J. Chem.
Soc., Perkin Trans. 1 1994, 521–526.
5. Kuroda, C.; Nogami, H.; Ohnishi, Y.; Kimura, Y.; Satoh, J. Y.
Tetrahedron 1997, 53, 839–858.
3.7. Treatment of 17 and 20 with Ms2O or MsCl
6. For related studies reported from our laboratory: (a) Kuroda,
C.; Kasahara, T.; Akiyama, K.; Amemiya, T.; Kunishima, T.;
Kimura, Y. Tetrahedron 2002, 58, 4493–4504. (b) Kuroda, C.;
Koshio, H.; Koito, A.; Sumiya, H.; Musase, A.; Hirono, Y.
Tetrahedron 2000, 56, 6441–6455. (c) Kuroda, C.; Murase, A.;
Suzuki, H.; Endo, T.; Anzai, S. Bull. Chem. Soc. Jpn. 1998, 71,
1639–1647.
Compound 20 was treated with Ms2O, and 17 was treated
with MsCl following the cyclization of the corresponding
(E)-isomers. Compound 17 afforded only a complex
mixture, while 20 (32.0 mg, 0.09 mmol) afforded 21
(17.1 mg, 77%) after florisil column chromatography
using pentane as eluent.
7. (a) Kuroda, C.; Honda, S.; Nagura, Y.; Koshio, H.; Shibue, T.;
Takeshita, T. Tetrahedron 2004, 60, 319–331. (b) Kuroda, C.;
Koshio, H. Chem. Lett. 2000, 962–963.
3.7.1. 6-(2-Methylprop-2-enylidene)-3-phenylcyclohex-
1-ene (19). This compound could not be isolated in the
pure form. The following data were assigned from a
complex mixture of hydrocarbon products. 1H NMR
(CDCl3) dZ1.92 (3H, s, Me), 3.54 (1H, br, CHPh), 4.89
(1H, s, C]CHH), 5.02 (1H, s, C]CHH), 5.80 (1H, s,
CH2]C–CH]C), 5.86 (1H, dd, JZ2.5, 9.4 Hz, CH]CH),
6.24 (1H, dd, JZ1.3, 9.4 Hz, CH]CH), and 7.19–7.34 (5H,
m, Ph); MS m/z 210 (MC, 18%), 195 (9), 167 (14), 106
(100), and 91 (76).
8. (a) Trost, B. M. Angew. Chem., Int. Ed. Engl. 1986, 25, 1–20.
(b) Chan, D. M. T. In Cycloaddition Reactions in Organic
Synthesis; Kobayashi, S., Jørgensen, K. A., Eds.; Wiley:
Weinheim, 2002; pp 57–84.
9. (a) Giguere, R. J.; Duncun, S. M.; Bean, J. M.; Purvis, L.
Tetrahedron Lett. 1988, 29, 6071–6074. (b) Hoffmann,
H. M. R.; Eggert, U.; Gibbels, U.; Giesel, K.; Koch, O.; Lies,
R.; Rabe, J. Tetrahedron 1988, 44, 3899–3917. (c) Hoffmann,
H. M. R.; Henning, R. Helv. Chim. Acta 1983, 66, 828–841.
10. (a) Suzuki, H.; Monda, A.; Kuroda, C. Tetrahedron Lett. 2001,
42, 1915–1917. (b) Suzuki, H.; Kuroda, C. Tetrahedron 2003,
59, 3157–3174.
3.7.2. 4-t-Butyl-1-(3-methylbuta-1,3-dienyl)cyclohex-1-
ene (21). An oil; IR (neat) 2956, 1620, 1468, 1363, and
1
958 cmK1; H NMR (C6D6Z7.15) dZ0.80 (9H, s, t-Bu),
1.02–1.20 (2H, m), 1.68–2.07 (4H, m), 1.86 (3H, s, Me),
2.27–2.35 (1H, m), 4.99 (1H, br s), 5.08 (1H, br s),
5.72–5.79 (1H, m), 6.38 (1H, d, JZ16.0 Hz), and 6.41 (1H,
d, JZ16.0 Hz); 13C NMR (C6D6Z128.0) dZ18.8, 24.1,
26.2, 27.2 (3C), 27.9, 32.1, 44.4, 115.8, 130.6, 132.6, 135.9,
and 142.7 (one carbon was not identified because of
overlapping with the solvent signal); MS m/z 204 (MC,
13%), 189 (2), 147 (11), 133 (14), 119 (17), 105 (88),
11. Suzuki, H.; Kuroda, C. J. Chem. Res. (S) 2003, 310–312.
12. (a) Booker-Milburn, K. I.; Thompson, D. F. Tetrahedron 1995,
51, 12955–12962. (b) Nakatani, K.; Takada, K.; Isoe, S.
J. Org. Chem. 1995, 60, 2466–2473.
13. Axelrod, E. H.; Milne, G. M.; van Tamelen, E. E. J. Am. Chem.
Soc. 1970, 92, 2139–2141.
14. Henning, R.; Hoffmann, H. M. R. Tetrahedron Lett. 1982, 23,
2305–2308.