Copper(I) tert-butoxide-promoted allylation of β-triphenylsilyl allylic alcohols via 1,3 Csp2-to-o silyl migration

Article abstract of DOI:10.1055/s-2004-822404

The substitution of the silyl group in vinylsilanes by an allylic group proceeded when β-triphenylsilylallyl alcohols were treated with copper(I) tert-butoxide and allylic halides. This reaction is the first synthetic application of 1,3 C^sp2-to-O silyl migration which provides a useful method for generation of vinyl anion equivalents.

Full text of DOI:10.1055/s-2004-822404

1504
PAPER
Copper(I) tert-Butoxide-Promoted Allylation of b-Triphenylsilyl Allylic
Alcohols via 1,3 Csp2-to-O Silyl Migration
Allylation of
b
-Tr
i
k
phenylsilyl
A
i
llylic
r
A
lcoholsa Tsubouchi, Miki Itoh, Kotaro Onishi, Takeshi Takeda*
Department of Applied Chemistry, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
Fax +81(42)3887034; E-mail: takeda-t@cc.tuat.ac.jp
Received 2 May 2004
rapidly protonated, as it forms, with the unreacted alcohol.
Independently Sato and coworkers found a similar rear-
rangement of several 1-(hydroxyalkyl)-1-alkenylsilanes
by treatment with a catalytic amount of NaH in HMPA or
Abstract: The substitution of the silyl group in vinylsilanes by an
allylic group proceeded when b-triphenylsilylallyl alcohols were
treated with copper(I) tert-butoxide and allylic halides. This reac-
tion is the first synthetic application of 1,3 Csp2-to-O silyl migration
which provides a useful method for generation of vinyl anion equiv- KH in THF.2h,i A formal 1,3 Csp2-to-O silyl migration was
also observed in the Red-Al® reduction of 4-siloxy prop-
alents.
argylic alcohol, though its mechanism is ambiguous.2j All
Key words: allylations, allylic alcohols, copper alkoxides, silyl
rearrangement, silyl ethers
these preceding studies indicate that no prospect of prac-
tical use of the silyl migration in organic synthesis has yet
emerged. Here we describe the copper(I) tert-butoxide (1)
promoted coupling of b-triphenylsilylallyl alcohols 2 with
allylic halides 3 via the 1,3 Csp2-to-O silyl migration to
The Brook-type rearrangement of silicon from carbon to
oxygen is a useful method for the preparation of reactive
organometallic species from organosilicon compounds.1
The generated active species have been employed for fur-
ther transformations even in the case where the equilibri-
um is unfavorable to its formation by virtue of
incorporation of a subsequent irreversible process. Al-
though the Csp3-to-O silyl migration has been frequently
employed for organic synthesis, there has been limited
synthetic application of the Csp2-to-O silyl migration.
Since this migration would be an attractive way for the
generation of synthetically useful vinylmetal species,2 we
studied the copper(I) alkoxide-promoted 1,4 silyl migra-
tion from Csp2-to-O leading to the formation of vinyl and
arylcopper species.3
form triphenylsilyl ethers of dienyl alcohols
(Scheme 1).
4
Starting materials 2 were readily prepared from commer-
cially available triphenylvinylsilanes 5 using the literature
procedures as shown in Scheme 2. The a-bromovinylsi-
lanes 6 was obtained by treatment of 5 with bromine fol-
lowed by the elimination of HBr with diethylamine.4 The
reaction of a-lithiovinylsilanes, generated by halogen–
metal exchange of 6 with n-butyllithium, with aldehydes
afforded 2.5
Ph3Si
Ph3Si
Ph3Si
1) nBuLi
1) Br2
R1
OH
Br
2) Et2NH
2) R1CHO
We expected that our methodology could be extended to
1,3 Csp2-to-O silyl migration, which has not been thor-
oughly studied so far. Wilson et al. investigated such rear-
rangement of 1-[1-(trimethylsilyl)vinyl]adamantan-1-ol
using potassium hydride as a base. They observed that
only the protodesilylated product was formed and deuteri-
um was not incorporated at the vinyl carbon when the re-
action was quenched with D2O.2g These results imply that
a vinyl anion species generated by the silyl migration is
5
6
2
Scheme 2
The coupling reactions of 2 with several allylic halides 3
were performed in the presence of copper(I) tert-butoxide
(1) and the results are summarized in Table 1. Successive
treatment of 5-phenyl-2-(trimethylsilyl)pent-1-en-3-ol
(2a) with 1 (1.1 equiv), prepared in situ by reaction of cop-
R3
R3
R2
R2
Ph3Si
R2
1) CuOtBu 1
R1
R2
R1
R1
+
R3
OH
R2
X
2)
Ph3SiO
α-4
Ph3SiO
2
γ-4
R2
3
Scheme 1
SYNTHESIS 2004, No. 9, pp 1504–1508
x
x
.
x
x
.2
0
0
4
Advanced online publication: 08.06.2004
DOI: 10.1055/s-2004-822404; Art ID: C03504SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
Allylation of b-Triphenylsilyl Allylic Alcohols
1505
Table 1 Copper(I) tert-Butoxide-Promoted Allylation of b-Triphe-
nylsilyl Allylic Alcohols 2a
per(I) iodide with lithium tert-butoxide,6 and methallyl
chloride 3a (2.0 equiv) at room temperature gave 4a in
48% yield with a 33% recovery of the starting material 2a
(Run 1). When 2.0 equivalents of 1 were used, the yield of
2a was significantly improved to 83% (Run 2), but the
yield was not improved with further increase in the
amount of 1. Addition of a premixed solution of 2a and 3a
to 1 gave 4a in slightly better yield (Run 3). Under the op-
timized conditions, the coupling reactions of several b-
triphenylsilylallyl alcohols 2 with allylic halides 3 were
performed and the allylation products 4 were obtained in
good to high yields. In the case of the reactions using pre-
nyl chloride, the formal SN2 and SN2¢ products a-4 and
g-4 were produced and the former was always the pre-
dominant product.
Run Allyllic Alcohol 2
Allylic Halide 3
Product 4
(Yield %)
1b
4a (48)
3a
2a
2c
3
2a
2a
2a
3a
3a
4a (83)
4a (87)
4b (82)
4
3b
5
6
2a
a-4c (73);
g-4c (20)
In contrast to the reactions of the triphenylsilylvinylsilane
2 described above, the similar allylation of the trimethyl-
silyl counterpart 7 with methallyl chloride 3a resulted in
the formation of only a trace amount of the C-allylation
product 8 along with the major O-allylation product 9
(Scheme 3).
3c
3a
4d (90)
2b
2b
Ph
Me3Si
7
8
3b
3c
4e (81)
Ph
Ph
Me3Si
1) CuOtBu 1
2b
a-4f (55);
g-4f (22)
+
O
OH
Cl
2)
7
Me3SiO
8 (trace)
9
3a
4g (83)
9 (36%)
3a
Scheme 3
2c
2c
We tentatively assume that the present allylation involves
the formation of vinylcopper species 10 as illustrated in
Scheme 4. The intermediary hypercoordinated silicate 11
is formed from the copper alkoxide 12 as previously sug-
gested for the 1,3 silyl migration2g,7 and is transformed
into the vinylcopper species 10 which reacts with allylic
halide 3 to give the silyl ether of dienyl alcohol 4. The dif-
ference in the reactivity between the triphenylsilyl- and
trimethylsilyl-substituted derivatives 2 and 7 could be ex-
plained by the nature of the substituents on the silyl group;
the electron-withdrawing phenyl group, in contrast to the
electron-donating methyl group, would stabilize the inter-
mediate silicate 11 to facilitate the silyl migration.5,8 Al-
though it is unclear at present why two equivalents of
copper(I) tert-butoxide 1 are indispensable to complete
the reaction, it might be possible to assume that an addi-
tional equivalent of 1 takes part in an activation of orga-
nocopper species through cuprate formation. Unlike in the
case of vinylmetal species formed by the silyl migration
from alkali metal alkoxides, the protonation of the vinyl-
copper species 10 thus generated with the unreacted alco-
hol 2 or tert-butyl alcohol produced during the reaction
would be relatively slow.
10
3b
3c
4h (81)
11
2c
a-4i (47);
g-4i (14)
12
3a
4j (91)
2d
2d
13
14
3b
4k (77)
4k (72)
2d
3d
3c
15
16
2d
a-4l (52);
g-4l (17)
3a
4m (75)
2e
2e
17
18
3b
3c
4n (66)
2e
a-4o (58);
g-4o (16)
a All reactions were performed in a procedure similar to that described
in the text, unless otherwise noted.
b 1.5 equiv of 1 were used. The halide 3 was added 10 min after addi-
tion of 2 and the reaction was continued for 6 h.
c The halide 3 was added 10 min after addition of 2.
Synthesis 2004, No. 9, 1504–1508 © Thieme Stuttgart · New York

1506
A. Tsubouchi et al.
PAPER
5.62–5.76 (m, 1 H), 6.97–7.02 (m, 2 H), 7.10–7.26 (m, 3 H), 7.32–
7.47 (m, 9 H), 7.57–7.67 (m, 6 H).
13C NMR (CDCl3): d = 31.2, 35.2, 37.4, 76.7, 112.2, 116.4, 125.6,
127.7, 128.2, 128.3, 129.9, 134.5, 135.5, 136.1, 142.1, 148.5.
Cu+
O
Ph3Si
OCu
1
Ph3Si
2
R1
- tBuOH
R1 12
11
Anal. Calcd for C32H32OSi: C, 83.43; H, 7.00. Found: C, 83.20; H,
7.34.
Cu
3
OSiPh3
4
- CuX
Mixture of 5-Methyl-2-[3-phenyl-1-(triphenylsiloxy)pro-
pyl]hexa-1,4-diene (a-4c) and 3,3-Dimethyl-2-[3-phenyl-1-
(triphenylsiloxy)propyl]penta-1,4-diene (g-4c)
R1
10
Scheme 4
IR (neat): 3068, 3026, 2927, 1453, 1428, 1116, 1076, 741, 698 cm–1.
1H NMR (CDCl3): d = 0.92 (s, 0.66 H), 1.00 (s, 0.66 H), 1.53 (s,
2.34 H), 1.68 (s, 2.34 H), 1.78–1.92 (m, 2 H), 2.38–2.82 (m, 3.56
H), 4.36 (t, J = 6.0 Hz, 0.78 H), 4.41 (t, J = 5.0 Hz, 0.22 H), 4.73–
4.82 (m, 1.22 H), 4.94 (s, 0.78 H), 5.06 (dd, J = 7.3, 7.3 Hz, 0.78 H),
5.17 (d, J = 0.9 Hz, 0.22 H), 5.51 (dd, J = 10.6, 17.4 Hz, 0.22 H),
5.54 (s, 0.22 H), 6.93–7.03 (m, 2 H), 7.08–7.24 (m, 3 H), 7.31–7.46
(m, 9 H), 7.56–7.69 (m, 6 H).
13C NMR (CDCl3): d = 17.6, 25.7, 26.2, 26.6, 29.6, 31.3, 31.4, 37.5,
41.0, 41.2, 72.1, 76.7, 110.8, 111.0, 111.4, 121.6, 125.5, 125.6,
127.67, 127.71, 128.18, 128.22, 128.30, 128.33, 129.9, 133.0,
134.6, 134.8, 135.5, 135.7, 142.3, 142.6, 146.8, 149.0, 157.0.
In conclusion, we have demonstrated the first synthetic
application of 1,3 Csp2-to-O silyl migration, which enable
us to prepare vinylcopper species from various b-triphe-
nylsilylallyl alcohols. The generated vinylmetal species
react with allylic halides to give the coupling products.
Further study on the preparation of organometallic species
by silyl migration is currently underway.
1H NMR (300 MHz) and 13C NMR (75 MHz) spectra were recorded
using TMS as internal standard. Chemical shifts (d) are quoted in
parts per million from TMS for 1H NMR and CDCl3 for 13C NMR
spectra. IR absorptions are reported in cm–1. All reactions were per-
formed under argon in dried glassware. DMF was distilled from
CaH2 under reduced pressure. Column chromatography was carried
out using Merck aluminum oxide 90 deactivated by addition of H2O
(5 wt%).
Anal. Calcd for C34H36OSi: C, 83.56; H, 7.42. Found: C, 83.17; H,
7.52.
2-Methyl-4-[3-phenyl-2-phenethyl-1-(triphenylsiloxy)pro-
pyl]penta-1,4-diene (4d)
IR (neat): 3068, 3025, 2925, 1495, 1453, 1428, 1116, 898, 741, 699
cm–1.
1H NMR (CDCl3): d = 1.34 (s, 3 H), 2.02–2.16 (m, 1 H), 2.28 (d,
J = 14.5 Hz, 1 H), 2.44 (d, J = 15.0 Hz, 1 H), 2.49–2.68 (m, 3 H),
3.04 (dd, J = 3.7, 13.9 Hz, 1 H), 4.21 (s, 1 H), 4.29 (s, 1 H), 4.55 (s,
1 H), 4.88 (s, 1 H), 5.28 (s, 1 H), 6.55–6.59 (m, 2 H), 7.00–7.47 (m,
17 H), 7.58–7.69 (m, 6 H).
13C NMR (CDCl3): d = 21.6, 34.5, 36.1, 42.1, 46.5, 75.7, 113.1,
113.3, 125.5, 125.6, 127.7, 128.0, 128.2, 129.0, 129.2, 129.9, 134.6,
135.8, 141.0, 141.7, 142.5, 146.5.
Copper(I) tert-Butoxide-Promoted Allylation of the b-Triphe-
nylsilylallyl Alcohol (2a) with Methallyl Chloride (3a); 2-Meth-
yl-4-[3-phenyl-1-(triphenylsiloxy)propyl]penta-1,4-diene (4a);
Typical Procedure
CuI (76 mg, 0.40 mmol) and DMF (0.6 mL) were placed in a flask
and cooled to 0 °C. t-BuOLi (0.94 M in THF, 0.47 mL, 0.44 mmol)
was added under argon and the mixture was stirred for 30 min at
25 °C. A DMF (1.4 mL) solution of 2a (84 mg, 0.20 mmol) and 3a
(36 mg, 0.40 mmol) was added to the mixture. After stirring for 3 h,
the reaction mixture was diluted with hexane. The mixture was ap-
plied to a filter pad of Celite to remove copper salts and the pad was
washed with hexane, CH2Cl2, and Et2O. The solvent was removed
under reduced pressure and the residue was purified by chromatog-
raphy (hexane) to yield the triphenylsilyl ether 4a (83 mg, 87%). In
a similar manner, the triphenylsilyl ethers of dienyl alcohols 4b–o
were obtained.
Anal. Calcd for C40H40OSi: C, 85.06; H, 7.14. Found: C, 85.09; H,
7.20.
2-[3-Phenyl-2-phenethyl-1-(triphenylsiloxy)propyl]penta-1,4-
diene (4e)
IR (neat): 3068, 3025, 2925, 1495, 1453, 1428, 1116, 911, 741, 700
cm–1.
IR (neat): 3068, 2929, 1648, 1590, 1454, 1428, 1116, 903, 741, 699
cm–1.
1H NMR (CDCl3): d = 2.05–2.17 (m, 1 H), 2.27 (dd, J = 7.7, 15.8
Hz, 1 H), 2.48–2.62 (m, 3 H), 2.69 (dd, J = 8.5, 11.2 Hz, 1 H), 3.01
(dd, J = 4.6, 13.9 Hz, 1 H), 4.27 (d, J = 1.5 Hz, 1 H), 4.64 (d,
J = 17.1 Hz, 1 H), 4.78 (d, J = 10.1 Hz, 1 H), 4.84 (s, 1 H), 5.13 (s,
1 H), 5.20–5.36 (m, 1 H), 6.62–6.67 (m, 2 H), 7.02–7.47 (m, 17 H),
7.63 (dd, J = 1.5, 7.9 Hz, 6 H).
13C NMR (CDCl3): d = 34.8, 36.1, 37.2, 46.7, 113.2, 116.3, 125.5,
125.6, 127.7, 128.0, 128.2, 129.0, 129.2, 129.9, 134.6, 135.6, 135.7,
141.0, 141.5, 147.7.
1H NMR (CDCl3): d = 1.58 (s, 3 H), 1.86 (dt, J = 5.7, 8.3 Hz, 2 H),
2.43–2.59 (m, 2 H), 2.69 (d, J = 15.2 Hz, 1 H), 2.78 (d, J = 15.2 Hz,
1 H), 4.39 (t, J = 5.6 Hz, 1 H), 4.64 (d, J = 1.1 Hz, 1 H), 4.76 (s, 1
H), 4.88 (d, J = 1.3 Hz, 1 H), 5.12 (d, J = 0.9 Hz, 1 H), 6.95–7.01
(m, 2 H), 7.08–7.24 (m, 3 H), 7.32–7.46 (m, 9 H), 7.60–7.67 (m, 6
H).
13C NMR (CDCl3): d = 21.8, 31.0, 37.3, 40.4, 76.0, 112.5, 113.1,
125.6, 127.7, 128.2, 128.3, 129.9, 134.6, 135.6, 142.3, 143.0, 147.2.
Anal. Calcd for C39H38OSi: C, 85.04; H, 6.95. Found: C, 84.73; H,
6.94.
Anal. Calcd for C33H34OSi: C, 83.49; H, 7.22. Found: C, 83.51; H,
7.38.
Mixture of 5-Methyl-2-[3-phenyl-2-phenethyl-1-(triphenylsil-
oxy)propyl]hexa-1,4-diene (a-4f) and 3,3-Dimethyl-2-[3-phe-
nyl-2-phenethyl-1-(triphenylsiloxy)propyl]penta-1,4-diene (g-
4f)
2-[3-Phenyl-1-(triphenylsiloxy)propyl]penta-1,4-diene (4b)
IR (neat): 3068, 2934, 1428, 1117, 1076, 913, 741, 699 cm–1.
1H NMR (CDCl3): d = 1.77–1.96 (m, 2 H), 2.46–2.54 (m, 2 H), 2.70
(dd, J = 7.5, 8.2 Hz, 1 H), 2.87 (dd, J = 6.5, 8.2 Hz, 1 H), 4.36 (t,
J = 6.0 Hz, 1 H), 4.82 (d, J = 1.7 Hz, 1 H), 4.94–5.03 (m, 3 H),
IR (neat): 3067, 3025, 2969, 2926, 1495, 1453, 1428, 1116, 1038,
983, 909, 741, 700 cm–1.
Synthesis 2004, No. 9, 1504–1508 © Thieme Stuttgart · New York

PAPER
Allylation of b-Triphenylsilyl Allylic Alcohols
1507
1H NMR (CDCl3): d = 0.47 (s, 0.87 H), 0.71 (s, 0.87 H), 1.31 (s,
2.13 H), 1.56 (s, 2.13 H), 1.96–2.18 (m, 1 H), 2.30 (dd, J = 7.6, 16.2
Hz, 0.71 H), 2.40–2.77 (m, 3.71 H), 3.03 (dd, J = 4.2, 14.1 Hz, 0.71
H), 3.24 (dd, J = 2.5, 13.8 Hz, 0.29 H), 4.27 (s, 0.71 H), 4.47 (s, 0.29
H), 4.58 (dd, J = 1.2, 17.3 Hz, 0.29 H), 4.64 (dd, J = 1.2, 10.5 Hz,
0.29 H), 4.68 (dd, J = 7.7, 7.7 Hz, 0.71 H), 4.83 (s, 0.71 H), 5.13 (s,
0.71 H), 5.14 (s, 0.29 H), 5.32 (dd, J = 10.5, 17.3 Hz, 0.29 H), 5.55
(s, 0.29 H), 6.40–6.46 (m, 0.58 H), 6.54–6.64 (m, 1.42 H), 6.93–
7.75 (m, 23 H).
13C NMR (CDCl3): d = 17.4, 25.2, 25.6, 27.9, 31.7, 33.2, 34.7, 36.1,
36.3, 40.7, 46.6, 47.1, 72.9, 76.5, 110.4, 112.5, 113.3, 121.5, 125.4,
125.45, 125.53, 127.69, 127.71, 127.8, 128.0, 128.17, 128.21,
129.0, 129.2, 129.3, 129.4, 129.82, 129.84, 132.7, 134.7, 134.8,
135.5, 135.7, 135.9, 141.00, 141.04, 141.7, 142.2, 147.4, 148.4,
154.8.
2-Methyl-4-[phenyl(triphenylsiloxy)methyl]penta-1,4-diene
(4j)
IR (neat): 3069, 2913, 1453, 1428, 1189, 1116, 1028, 894, 861, 741,
698 cm–1.
1H NMR (CDCl3): d = 1.41 (s, 3 H), 2.38 (d, J = 15.2 Hz, 1 H), 2.61
(d, J = 15.2 Hz, 1 H), 4.49 (s, 1 H), 4.66 (s, 1 H), 4.87 (s, 1 H), 5.27
(s, 1 H), 5.41 (s, 1 H), 7.17–7.42 (m, 14 H), 7.51–7.60 (m, 6 H).
13C NMR (CDCl3): d = 21.6, 40.4, 78.0, 111.3, 112.8, 126.9, 127.2,
127.7, 127.9, 129.9, 134.3, 135.5, 142.2, 143.0, 148.1.
Anal. Calcd for C31H30OSi: C, 83.36; H, 6.77. Found: C, 83.35; H,
7.10.
2-[Phenyl(triphenylsiloxy)methyl]penta-1,4-diene (4k)
IR (neat): 3069, 1429, 1117, 1065, 914, 741, 698 cm–1.
1H NMR (CDCl3): d = 2.42 (dd, J = 7.3, 16.3 Hz, 1 H), 2.70 (dd,
J = 6.4, 16.5 Hz, 1 H), 4.82 (dd, J = 0.6, 1.6 Hz, 1 H), 4.83 (ddd,
J = 1.7, 3.6, 17 Hz, 1 H), 4.90 (dddd, J = 1.1, 1.1, 2.2, 10.1 Hz, 1 H),
5.25 (dd, J = 1.1, 1.5 Hz, 1 H), 5.31 (s, 1 H), 5.53 (dddd, J = 6.7, 7.2,
10.2, 17.1 Hz, 1 H), 7.17–7.43 (m, 14 H), 7.53–7.60 (m, 6 H).
13C NMR (CDCl3): d = 35.3, 78.7, 111.2, 116.3, 126.6, 127.1,
127.7, 128.0, 129.9, 134.2, 135.5, 135.8, 142.2, 149.2.
Anal. Calcd for C41H42OSi: C, 85.07; H, 7.31. Found: C, 85.05; H,
7.52.
2-[Cyclohexyl(triphenylsiloxy)methyl]-4-methylpenta-1,4-di-
ene (4g)
IR (neat): 3067, 2920, 1648, 1429, 1119, 1038, 894, 852, 740, 700
cm–1.
1H NMR (CDCl3): d = 0.77–0.95 (m, 2 H), 1.00–1.22 (m, 3 H),
1.32–1.75 (m, 5 H), 1.54 (s, 3 H), 1.93 (br d, J = 12.5 Hz, 1 H), 2.56
(d, J = 16.1 Hz, 1 H), 2.71 (d, J = 15.6 Hz, 1 H), 4.01 (d, J = 6.6 Hz,
1 H), 4.57 (s, 1 H), 4.75 (s, 1 H), 4.76 (s, 1 H), 4.88 (s, 1 H), 7.30–
7.45 (m, 9 H), 7.58–7.66 (m, 6 H).
13C NMR (CDCl3): d = 22.0, 26.3, 26.4, 26.5, 28.7, 29.7, 40.1, 41.8,
82.1, 112.7, 113.3, 127.6, 129.7, 134.8, 135.8, 143.2, 146.7.
Anal. Calcd for C30H28OSi: C, 83.29; H, 6.52. Found: C, 83.32; H,
6.58.
Mixture of 5-Methyl-2-[phenyl(triphenylsiloxy)methyl]hexa-
1,4-diene (a-4l) and 3,3-Dimethyl-2-[phenyl(triphenylsil-
oxy)methyl]penta-1,4-diene (g-4l)
IR (neat): 3068, 3050, 3027, 3000, 2968, 2925, 2855, 1428, 1117,
1085, 1063, 1028, 741, 698 cm–1.
Anal. Calcd for C31H36OSi: C, 82.25; H, 8.02. Found: C, 81.90; H,
8.06.
1H NMR (CDCl3): d = 0.76 (s, 0.72 H), 0.89 (s, 0.72 H), 1.36 (s,
2.28 H), 1.60 (s, 2.28 H), 2.38 (dd, J = 7.9, 16.9 Hz, 0.76 H), 2.59
(dd, J = 6.7, 16.8 Hz, 0.76 H), 4.68 (dd, J = 1.3, 10.5 Hz, 0.24 H),
4.71 (dd, J = 1.3, 17.6 Hz, 0.24 H), 4.80 (d, J = 1.5 Hz, 0.76 H),
4.91 (dd, J = 7.2, 7.2 Hz, 0.76 H), 5.22 (s, 0.76 H), 5.26 (d, J = 1.3
Hz, 0.24 H), 5.30 (s, 1 H), 5.38 (dd, J = 10.5, 17.4 Hz, 0.24 H), 5.88
(s, 0.24 H), 7.16–7.59 (m, 20 H).
13C NMR (CDCl3): d = 17.4, 25.6, 26.5, 27.3, 29.8, 41.2, 75.5, 78.9,
110.3, 110.6, 110.8, 121.4, 126.6, 127.1, 127.6, 127.7, 127.87,
127.90, 128.2, 129.8, 129.9, 133.0, 134.3, 134.4, 135.5, 135.56,
135.61, 142.4, 143.1, 147.1, 149.9, 156.2.
2-[Cyclohexyl(triphenylsiloxy)methyl]penta-1,4-diene (4h)
IR (neat): 3069, 2925, 2851, 1448, 1428, 1116, 998, 913, 846, 741,
699 cm–1.
1H NMR (CDCl3): d = 0.70–0.91 (m, 2 H), 0.96–1.27 (m, 3 H),
1.34–1.73 (m, 5 H), 2.03 (br d, J = 12.8 Hz, 1 H), 2.58 (dd, J = 7.5,
16.9 Hz, 1 H), 2.84 (dd, J = 6.5, 16.8 Hz, 1 H), 3.94 (d, J = 7.7 Hz,
1 H), 4.71 (ddd, J = 1.7, 1.7, 1.7 Hz, 1 H), 4.74 (s, 1 H), 4.92 (d,
J = 18.3 Hz, 1 H), 4.97 (d, J = 10.3 Hz, 1 H), 5.51–5.64 (m, 1 H),
7.30–7.45 (m, 9 H), 7.57–7.64 (m, 6 H).
13C NMR (CDCl3): d = 26.16, 26.20, 26.5, 29.38, 29.43, 34.9, 41.7,
82.8, 113.0, 116.4, 127.6, 129.7, 134.7, 135.7, 136.0, 148.0.
Anal. Calcd for C32H32OSi: C, 83.43; H, 7.00. Found: C, 83.22; H,
7.09.
Anal. Calcd for C30H34OSi: C, 82.14; H, 7.81. Found: C, 82.00; H,
7.96.
2-[4-Biphenylyl(triphenylsiloxy)methyl]-4-methylpenta-1,4-di-
ene (4m)
IR (neat): 3069, 2916, 1486, 1428, 1117, 1074, 864, 765, 741, 699
Mixture of 5-Methyl-2-[cyclohexyl(triphenylsiloxy)meth-
yl]hexa-1,4-diene (a-4i) and 3,3-Dimethyl-2-[cyclohexyl(triphe-
nylsiloxy)methyl]penta-1,4-diene (g-4i)
cm–1.
1H NMR (CDCl3): d = 1.26 (s, 3 H), 2.43 (d, J = 15.2 Hz, 1 H), 2.66
(d, J = 15.4 Hz, 1 H), 4.53 (s, 1 H), 4.69 (s, 1 H), 4.91 (s, 1 H), 5.32
(s, 1 H), 5.46 (s, 1 H), 7.26–7.47 (m, 16 H), 7.58 (dd, J = 1.6, 8.0
Hz, 8 H).
13C NMR (CDCl3): d = 21.6, 32.9, 40.6, 77.8, 111.4, 112.9, 126.6,
127.0, 127.1, 127.4, 127.7, 128.7, 129.9, 134.2, 135.5, 140.0, 141.0,
141.3, 143.0, 148.0.
IR (neat): 3068, 2925, 2851, 1428, 1116, 901, 700 cm–1.
1H NMR (CDCl3): d = 0.71–1.83 (m, 9.46 H), 0.89 (s, 0.69 H), 0.96
(s, 0.69 H), 1.40 (d, J = 12.1 Hz, 0.77 H), 1.50 (s, 2.31 H), 1.67 (s,
2.31 H), 2.00 (br d, J = 11.9 Hz, 0.77 H), 2.57 (dd, J = 7.4, 17.0 Hz,
0.77 H), 2.71 (dd, J = 7.1, 17.0 Hz, 0.77 H), 3.95 (d, J = 7.3 Hz,
0.77 H), 4.23 (s, 0.23 H), 4.67–4.81 (m, 2 H), 4.96 (dd, J = 7.3, 7.3
Hz, 0.77 H), 5.15 (d, J = 1.3 Hz, 0.23 H), 5.36 (s, 0.23 H), 5.48 (dd,
J = 10.5, 17.4 Hz, 0.23 H), 7.30–7.44 (m, 9 H), 7.58–7.66 (m, 6 H).
Anal. Calcd for C37H34OSi: C, 85.01; H, 6.56. Found: C, 85.31; H,
6.71.
13C NMR (CDCl3): d = 17.6, 25.7, 26.2, 26.3, 26.5, 26.9, 29.26,
29.31, 29.6, 31.5, 41.0, 41.9, 43.0, 76.8, 82.8, 110.4, 111.9, 112.3,
121.6, 127.48, 127.54, 129.66, 129.68, 132.7, 134.8, 135.1, 135.8,
135.9, 147.3, 148.4, 154.9.
2-[Biphenylyl(triphenylsiloxy)methyl]penta-1,4-diene (4n)
IR (neat): 3068, 3050, 3027,1486, 1428, 1117, 1074, 912, 858, 765,
742, 712, 698 cm–1.
Anal. Calcd for C32H38OSi: C, 82.35; H, 8.21. Found: C, 82.32; H,
8.25.
Synthesis 2004, No. 9, 1504–1508 © Thieme Stuttgart · New York

1508
A. Tsubouchi et al.
PAPER
1H NMR (CDCl3): d = 2.48 (dd, J = 7.5, 16.5 Hz, 1 H), 2.75 (dd,
J = 6.4, 16.5 Hz, 1 H), 4.80–4.95 (m, 3 H), 5.29 (s, 1 H), 5.37 (s, 1
H), 5.50–5.64 (m, 1 H), 7.26–7.49 (m, 16 H), 7.53–7.63 (m, 8 H).
13C NMR (CDCl3): d = 35.4, 78.5, 111.3, 116.4, 126.7, 127.0,
127.08, 127.13, 127.7, 128.7, 129.9, 134.2, 135.5, 135.8, 140.0,
141.0, 141.3, 149.2.
References
(1) (a) Brook, A. G. Pure Appl. Chem. 1966, 13, 215.
(b) Brook, A. G. Acc. Chem. Res. 1974, 7, 77. (c) Moser,
W. H. Tetrahedron 2001, 57, 2065. (d) Kira, M.; Iwamoto,
T. In The Chemistry of Organosilicon Compounds, Vol. 3;
Rappoport, Z.; Apeloig, Y., Eds.; Wiley: Chichester, 2001,
853.
Anal. Calcd for C36H32OSi: C, 84.99; H, 6.34. Found: C, 85.20; H,
6.39.
(2) (a) For 1,4 Csp2-to-O silyl migration, see: Spinazzé, P. G.;
Keay, B. A. Tetrahedron Lett. 1989, 30, 1765. (b) See also:
Kim, K. D.; Magriotis, P. A. Tetrahedron Lett. 1990, 31,
6137. (c) See also: Lautens, M.; Delanghe, P. H. M.; Goh, J.
B.; Zhang, C. H. J. Org. Chem. 1995, 60, 4213. (d) See
also: Bures, E.; Spinazzé, P. G.; Beese, G.; Hunt, I. R.;
Rogers, C.; Keay, B. A. J. Org. Chem. 1997, 62, 8741.
(e) See also: Moser, W. H.; Endsley, K. E.; Colyer, J. T. Org.
Lett. 2000, 2, 717. (f) See also: Moser, W. H.; Zhang, J.;
Lecher, C. S.; Frazier, T. L.; Pink, M. Org. Lett. 2002, 4,
1981. (g) For 1,3 Csp2-to-O silyl migration, see: Wilson, S.
R.; Georgiadis, G. M. J. Org. Chem. 1983, 48, 4143.
(h) See also: Sato, F.; Tanaka, Y.; Sato, M. J. Chem. Soc.,
Chem. Commun. 1983, 165. (i) See also: Urabe, H.; Sato, F.
J. Am. Chem. Soc. 1999, 121, 1245. (j) See also: Radinov,
R.; Schnurman, E. S. Tetrahedron Lett. 1999, 40, 243.
(3) (a) Taguchi, H.; Ghoroku, K.; Tadaki, M.; Tsubouchi, A.;
Takeda, T. Org. Lett. 2001, 3, 3811. (b) Taguchi, H.;
Ghoroku, K.; Tadaki, M.; Tsubouchi, A.; Takeda, T. J. Org.
Chem. 2002, 67, 8450. (c) Taguchi, H.; Miyashita, H.;
Tsubouchi, A.; Takeda, T. Chem. Commun. 2002, 2218.
(d) Taguchi, H.; Tsubouchi, A.; Takeda, T. Tetrahedron
Lett. 2003, 44, 5205. (e) Taguchi, H.; Takami, K.;
Tsubouchi, A.; Takeda, T. Tetrahedron Lett. 2004, 45, 429.
(4) Dawson, I. M.; Gregory, J. A.; Herbert, R. B.; Sammens, P.
G. J. Chem. Soc., Perkin Trans. 1 1988, 2585.
Mixture of 5-Methyl-2-[biphenylyl(triphenylsiloxy)meth-
yl]hexa-1,4-diene (a-4o) and 3,3-Dimethyl-2-[biphenylyl(tri-
phenylsiloxy)methyl]penta-1,4-diene (g-4o)
IR (neat): 3068, 2968, 2913, 1486, 1428, 1117, 1072, 862, 764, 741,
711 cm–1.
1H NMR (CDCl3): d = 0.80 (s, 0.66 H), 0.93 (s, 0.66 H), 1.38 (s,
2.34 H), 1.61 (s, 2.34 H), 2.43 (dd, J = 8.1, 16.5 Hz, 0.78 H), 2.63
(dd, J = 6.4, 16.9 Hz, 0.78 H), 4.71 (dd, J = 1.3, 10.5 Hz, 0.22 H),
4.74 (dd, J = 1.3, 17.4 Hz, 0.22 H), 4.83 (d, J = 1.7 Hz, 0.78 H),
4.93 (dd, J = 7.3, 7.3 Hz, 0.78 H), 5.25 (s, 0.78 H), 5.29 (dd, J = 1.0,
1.0 Hz, 0.22 H), 5.34 (s, 1 H), 5.42 (dd, J = 10.5, 17.4 Hz, 0.22 H),
5.91 (s, 0.22 H), 7.17–7.62 (m, 24 H).
13C NMR (CDCl3): d = 17.5, 25.6, 26.6, 27.3, 29.9, 41.3, 75.2, 78.7,
110.4, 110.7, 110.9, 121.4, 126.6, 126.7, 126.99, 127.01, 127.1,
127.6, 127.65, 127.69, 128.6, 128.68, 128.70, 129.8, 129.9, 133.0,
134.3, 134.4, 135.5, 135.6, 139.9, 140.0, 140.97, 141.02, 141.5,
142.2, 147.1, 149.9, 156.2.
Anal. Calcd for C38H36OSi: C, 85.03; H, 6.76. Found: C, 84.71; H,
7.00.
Acknowledgment
This research was supported by a Grant-in-Aid for Scientific Re-
search (No. 15550085) from Ministry of Education, Culture, Sports,
Science and Technology, Japan. This work was carried out under
the 21st Century COE program of ‘Future Nanomaterials’ in Tokyo
University of Agriculture & Technology.
(5) Chan, T. H.; Mychajlowskij, W.; Ong, B. S.; Harpp, D. N. J.
Org. Chem. 1978, 43, 1526.
(6) Tsuda, T.; Hashimoto, T.; Saegusa, T. J. Am. Chem. Soc.
1972, 94, 658.
(7) (a) Hudrlik, P. F.; Hudrlik, A. M.; Kulkarni, A. K. J. Am.
Chem. Soc. 1982, 104, 6809. (b) Kawashima, T. J.
Organomet. Chem. 2000, 661, 256; and references therein.
(8) For a similar reactivity order of the silyl migration, see:
Takaku, K.; Shinokubo, H.; Oshima, K. Tetrahedron Lett.
1998, 39, 2575.
Synthesis 2004, No. 9, 1504–1508 © Thieme Stuttgart · New York