Substituent-control of two modes of intramolecular reactions of allyloxy-silyllithiums and propargyloxy-silyllithiums

Article abstract of DOI:10.1246/bcsj.78.1520

Intramolecular reactions of the [(allyloxy)silyl]lithiums and the [(propargyloxy)silyl]lithiums have been investigated. The [(allyloxy)silyl] lithiums proceed in two reaction modes depending on the electronic effect of the substituents at the terminus of the olefin. The [(allyloxy)silyl]lithiums bearing hydrogen, n-C₆H₁₃, or trimethylsilyl substituent undergo the [2,3]-sila-Wittig rearrangement to afford the lithium allylsilanolates, while those bearing the phenyl, thienyl, or triphenylsilyl substituent experience the 4-exo-trig cyclization and subsequent 1,3-cycloelimination to give the lithium cyclopropylsilanolates. On the other hand, the [(propargyloxy)silyl]lithiums preferentially undergo the 4-exo-dig cyclization over the [2,3]-sila-Wittig rearrangement in all cases.

Full text of DOI:10.1246/bcsj.78.1520

1520 Bull. Chem. Soc. Jpn., 78, 1520–1527 (2005)
Ó 2005 The Chemical Society of Japan
Substituent-Control of Two Modes of Intramolecular Reactions
of Allyloxy-Silyllithiums and Propargyloxy-Silyllithiums
y
ꢀ;
Atsushi Kawachi, Hirofumi Maeda, and Kohei Tamao
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011
Received February 1, 2005; E-mail: kawachi@sci.hiroshima-u.ac.jp
Intramolecular reactions of the [(allyloxy)silyl]lithiums and the [(propargyloxy)silyl]lithiums have been investigat-
ed. The [(allyloxy)silyl]lithiums proceed in two reaction modes depending on the electronic effect of the substituents at
the terminus of the olefin. The [(allyloxy)silyl]lithiums bearing hydrogen, n-C6H13, or trimethylsilyl substituent undergo
the [2,3]-sila-Wittig rearrangement to afford the lithium allylsilanolates, while those bearing the phenyl, thienyl, or tri-
phenylsilyl substituent experience the 4-exo-trig cyclization and subsequent 1,3-cycloelimination to give the lithium cy-
clopropylsilanolates. On the other hand, the [(propargyloxy)silyl]lithiums preferentially undergo the 4-exo-dig cycliza-
tion over the [2,3]-sila-Wittig rearrangement in all cases.
The intramolecular reactions of organolithium reagents with
olefins have been extensively studied in organic synthesis. One
representative reaction is the Wittig rearrangement1 of ꢀ-allyl-
oxy organolithium compounds, which promises regio- and
stereoselective C–C bond formation along with the allylic
transposition. Another topic is the intramolecular carbolithia-
tion2 of olefins, which allows the regio- and stereoselective
cyclization.
When we turn our attention to analogous reactions of silyl-
lithium reagents,3 we notice that there have been only a few
examples of the corresponding reactions, despite the potential
utility of the regio- and stereoselective Si–C bond formation.
During the course of our studies on functionalized silyl
anions,4 we explored the preparation and reaction of [(allyl-
oxy)silyl]lithiums and found two novel reaction modes, as
shown in Scheme 1. One is the [2,3]-sila-Wittig rearrange-
ment,5 silicon analogues to the [2,3]-Wittig rearrangement.
prim-, sec-, and tert-Allyloxy-silyllithiums6 bearing an aliphat-
ic substituent at the terminus of the olefin, such as 1 (R = n-
C6H13), experienced the ‘‘[2,3]-Wittig’’ type rearrangement
to afford the lithium allylsilanolates through a suprafacial con-
certed mechanism accompanied by the allylic transposition
and the complete 1,3-chirality transfer.5b In contrast to this,
the sec-allyloxy-silyllithium 1 (R ¼ Ph) bearing a phenyl sub-
stituent at the terminus of the olefin undergoes the other type
of reaction,7,8 the 4-exo-trig cyclization via silyllithiation of
the olefin followed by the 1,3-cycloelimination. This reaction
proceeds in a stepwise manner to afford the lithium cyclopro-
pylsilanolate 3 as a single diastereomer, regardless of the E or
Z geometric isomer of the starting material, but keeping the
original enantiopurity at the allylic position in 1.5b
It was a surprise that just a change in the substituent at the
terminus of the olefin caused such a dramatic change in the re-
action modes of the [(allyloxy)silyl]lithiums. In order to clarify
the origin of the substituent effect on the two reaction modes,
we have carried out a detailed experimental study using sever-
al substituents at the terminus of the olefin. This report de-
scribes the results,9 together with some aspects of the analo-
gous [(propargyloxy)silyl]lithiums bearing substituents at the
acetylenic carbon atom.
Results and Discussion
Throughout this paper, the three carbon atoms of the allyl
and propargyl skeletons are numbered as shown in Chart 1.
Preparation of Substrates. The [(sec-allyloxy)silyl]stan-
nanes 4 bearing substituents at the terminus of the olefin were
prepared by the reaction of [(chloro)dimesitylsilyl]trimethyl-
stannane (5) with a variety of substituted sec-allyl alcohols10
6 in the presence of triethylamine and 4-(dimethylamino)pyri-
dine in refluxing THF, as shown in Scheme 2.5b The propargyl-
oxy derivatives 7 were similarly prepared by the reaction of 5
with substituted sec-propargyl alcohols10 8 (Scheme 2). Based
on these methods, we obtained the substrates containing the
following substituents: H- (a), n-C6H13- (Hex-) (b), Ph- (c),
3-(trimethylsilyl)thienyl- (Th-) (d), Me3Si- (e), and Ph3Si- (f).
Intramolecular Reactions of Substituted [(sec-Allyloxy)-
silyl]lithiums. The preparation and subsequent rearrange-
ment of the [(sec-allyloxy)silyl]lithiums 1 were performed
by treatment of the corresponding silylstannanes 4 with n-BuLi
Me
R
R
Me
R
Me
Mes2Si OLi
Mes
2Si
Li
O
Mes2Si OLi
R = Ph
R = n-C6H13
2
1
3
Scheme 1.
C3 C 2C1
C3 C2 C1
y Present address: Department of Chemistry, Graduate School of
Science, Hiroshima University, Kagamiyama 1-3-1, Higashi-
Hiroshima 739-8526
Chart 1.
Published on the web August 4, 2005; DOI 10.1246/bcsj.78.1520

A. Kawachi et al.
Bull. Chem. Soc. Jpn., 78, No. 8 (2005) 1521
(1.2–2.0 molar amt.) in THF at 0 ꢁC for 3 h, followed by
quenching with a 5% aqueous solution of NH4Cl, as shown
in Scheme 3. The products were isolated by column chroma-
tography. The Hex-substituted substrate 4b afforded the (E)-al-
lylsilanol 9b in 74% yield via the [2,3]-sila-Wittig rearrange-
ment, as previously reported.5b In addition to this, the non-sub-
stituted (4a) and the Me3Si-substituted (4e) substrates also se-
lectively gave (E)-allylsilanols 9a and 9e in 86% and 78%
yields, respectively. Thus these three substituents induce the
intramolecular nucleophilic attack of the silyl anion on the ex-
ternal carbon C(3) of the olefin in 1 (mode a in Scheme 3). The
E-preference can be explained by the analogy to the transition
states of the [2,3]-Wittig rearrangement.1a,11 Thus, as shown in
Scheme 4, the silyllithium 1 undergoes a suprafacial attack on
the olefin in the lower-energy conformer around the C(1)–C(2)
bond, which has a smaller 1,3-allylic strain (A1;3).5b
pylsilanols 10d and 10f in 64% and 71% yields, respectively.
These substituents selectively cause the intramolecular nucleo-
philic attack of the silyl anion on the internal carbon C(2) in
the olefin in 1 (mode b in Scheme 3). This 4-exo-trig cycliza-
tion, a favored process in Baldwin’s rules,12 affords the orga-
nolithium species 11 bearing the oxasilacyclobutane moiety,
which subsequently undergoes 1,3-cycloelimination13 to give
the cyclopropylsilanolates 3 (10 after hydrolysis).
The stereochemistry of 10c was previously determined as
(r-Si-trans,trans) by its X-ray crystallographic analysis.7 The
stereochemistry of 10d and 10f were also determined to be
(r-Si-trans,trans) by the NOE experiments and the coupling
1
constants in the H NMR spectra (see: Experimental section).
The stereochemical courses of 10d and 10f can be similarly ra-
tionalized to that of 10c, as shown in Scheme 5.5b,7 The intra-
molecular syn-silyllithiation via the favorable conformer hav-
ing a smaller A1;3 strain proceeds in the initial step, facilitated
by the electron-withdrawing group, to give 11(i). The inter-
mediate 11(i) is expected to be equilibrated with its epimer
11(ii) due to the configurationally labile carbanion bearing
the R group (R ¼ Ph, Th, and Ph3Si14 in Scheme 5). Subse-
quently, 1,3-cycloelimination involving the oxasilacyclobu-
tanes 11(i) and 11(ii) may take place with inversion or reten-
tion of the carbanion center C(3) and with inversion at the
In contrast, the Ph-substituted substrate 4c afforded the cy-
clopropylsilanol 10c in 68% yield under a similar reaction con-
dition5b,7 (Scheme 3). The Th-substituted (4d) and the Ph3Si-
substituted (4f) substrates also selectively gave the cyclopro-
R
Me
DMAP (x 0.2)
Et3N (x 2)
Me3Sn
R
Me
OH
+
Mes2Si Cl
Mes2Si
Me3Sn
O
THF
60 °C, 18 h
4d 70%
4b 61% 4e 73%
4c 77% 4f 76%
5
6a - f
4a 78%
2
Li
H
Me
H
R
1
3
Mes Si
2
H
R
R
DMAP (x 0.2)
Et3N (x 2)
O
Me3Sn
O
R
Me
OH
Me
Mes Si
2
+
Mes2Si Cl
3
H
H
1
2
THF
60 °C, 18 h
H Me
Li
Mes2Si
Me3Sn
O
A1,3
7e 35%
5
8b,c,e,f
7b 82%
7c 85% 7f 81%
favored
less favored
a: R = H
b: R = n-C6H13
c: R = Ph
d: R = Me Si
e: R = Me3Si
f: R = Ph3Si
3
S
(E)-2
(Z)-2
not formed
Scheme 2.
Scheme 4.
R
Me
R
Me
R
Me
(1), (2)
(1), (2)
Mes2Si
Me3Sn
4a - f
O
Mes2Si OH
Mes2Si OH
a: R = H
b: R = n-C6H13
e: R = Me3Si
c: R = Ph
d: R =
9a 86%
9b 74%
9e 78%
10c 68%
10d 64%
10f 71%
Me3Si
S
f: R = Ph3Si
2
R
Li
3
1
R
a
Me
R
Me
R
Me
Me
a
b
b
Mes2Si
O
Mes2Si OLi
Li
Mes2Si
11
O
Mes2Si OLi
2
1
3
(1) n-BuLi (x 2.0 (for 4a, b, e) or x 1.2 (for 4c, d, f)) / THF / 0 °C, 3 h
(2) 5% NH4Cl aq.
Scheme 3.

1522 Bull. Chem. Soc. Jpn., 78, No. 8 (2005)
Intramolecular Reactions of Silyllithiums
C(1) center.
bonds has been extensively studied.16,17 In contrast, it has been
well demonstrated that the silylmetallation to intramolecular
olefins catalyzed by transition metals undergoes 4-exo-trig
cyclization to afford oxasilacyclobutanes.18 The efficiency of
the silyllithiation in the present case may be attributed to the
activation of the olefins by the electron-withdrawing R groups
(R ¼ Ph, Th, and Ph3Si19 in Scheme 3) as well as to the intra-
molecular fashion of the reaction. These electron-withdrawing
substituents may also effectively stabilize the negative charge
generated on the R-bearing carbon atom C(3) in 11. The cyclo-
propane formation by 1,3-cycloelimination, in which the lithi-
ated carbon attacks the electrophilic carbon bearing the leaving
group, has been established by several research groups in the
last decade.13 The present reaction is essentially the same
when the silanolate anion is regarded as the leaving group.
Intramolecular Reactions of [(sec-Propargyloxy)silyl]-
lithiums. Since the carbon–carbon triple bond is also recep-
tive toward a silyl anion nucleophile,16c,f we next examined the
reaction modes of analogous [(sec-propargyloxy)silyl]lithiums
12 bearing substituents at the acetylenic carbon atom, as
shown in Scheme 6. The treatment of [(sec-propargyloxy)-
silyl]stannane 7 with n-BuLi gave rise to a complex mixture,
perhaps due to the high reactivity of n-BuLi toward the acety-
lene. Alternatively, MeLi was found to be effective for the Sn–
Li exchange of 7 by keeping the acetylene moiety intact. Thus,
the silylstannane 7 was treated with MeLi (2.0 molar amt.)20 in
THF at 0 ꢁC for 3 h, followed by quenching with a 5% aqueous
solution of NH4Cl. These results are summarized in Scheme 6.
The products were isolated by column chromatography.
It was found that the major product for each substituent was
a vinylsilane 13, in which the silicon group, attached to the
C(2) atom of an allyl alcohol moiety, contains a methyl group
arising from the MeLi used in excess for the Sn–Li exchange
reaction. Thus, the Ph-substituted (7c), the Me3Si-substituted
(7e), and the Ph3Si-substituted (7f) substrates afforded 13c,
13e, and 13f in 79%, 44%, and 50% yields, respectively. Only
the Hex-substituted substrate 7b gave the allenylsilanol 14b in
addition to the vinylsilane 13b in a 1:1 ratio.
In our preliminary communication,7 the regioselectivity of
the reaction of the silyllithium to the olefin (mode a vs mode
b) was rationalized in terms of orbital control: ab initio molec-
ular orbital calculations of allyloxysilanes bearing a propyl (in-
stead of hexyl) or a phenyl substituent at the terminus of the
olefin revealed that the propyl substituent maximizes the mo-
lecular orbital coefficient on C(3) in the LUMO, whereas the
phenyl substituent maximizes the molecular orbital coefficient
on C(2) in the LUMO.
To our knowledge, there has been no example of the silyl-
lithiation of olefins,15 while the silylcupration to C–C multiple
2
1
Mes Mes
Si
R
H
Me
H
3
H
O
Li
Li
O
R
Si
3
H
1
2
H Me
H
Mes Mes
favored
Li
A1,3
less favored
R
H
R
H
H
1
3
3
Li
H
1
2
2
Mes
Mes
Mes
Mes
epimerization
Si
Si
O
O
Me
Me
11(i)
11(ii)
ret.
inv.
R
Me
3
1
2
Mes Si OLi
2
(r-Si-trans,trans)-3
Scheme 5.
R
R
R
Me
OH
Me
(1), (2)
(1), (2)
Me
•
H
Mes
2Si
Mes2Si
Me3Sn
O
Mes2SiMe
OH
7b, c, e, f
14b 38%
13b 41%
13c 79%
13e 44%
13f 50%
b: R = n-C6H13
b: R = n-C6H13
c: R = Ph
e: R = Me3Si
f: R = Ph3Si
3
R
X
R
R'
•
R
Me
OLi
2
a
Me
b
1
Me
a
Li
Me
Li
b
Mes2Si
OLi
Mes2Si
Li
O
Mes2SiMe
Mes2Si
MeLi
O
15
12
16
17
(1) MeLi (x 2.0) / THF / 0 °C, 3 h
(2) 5% NH4Cl aq.
Scheme 6.

A. Kawachi et al.
Bull. Chem. Soc. Jpn., 78, No. 8 (2005) 1523
cal shifts were referenced to the internal benzene-d6 (1H 7.200
ppm; 13C 128.0 ppm) and CDCl3 (13C 77.00 ppm). The mass spec-
tra were measured at 70 eV using a JEOL JMS-DX300 mass spec-
trometer. The elemental analyses were performed at the Micro-
analysis Division of the Institute for Chemical Research, Kyoto
University. The analytical samples were purified by recycling re-
verse-phase liquid chromatography or recrystallization. Column
chromatography was performed using Kieselgel 60 (70–230
mesh) (Merck). Thin layer chromatography was performed on
plates of silica gel 60F-254 (Merck). Trimethylchlorostannane
was prepared by disproportionation between the tetramethylstan-
nane and dimethyldichlorostannane; the latter was kindly donated
from Nitto Kasei Co. 3-Butyn-2-ol (8a) and sodium dihydrobis(2-
methoxyethoxy)aluminate (Red-Al) were purchased from the
Aldrich Co., and used as received. 3-Buten-2-ol (6a) and 4-(di-
methylamino)pyridine were purchased from Nacalai Tesque and
used as received. Butyllithium in hexane was purchased from
Wako Pure Chemical Industries. Granular lithium was purchased
from Chemetall Gesellshaft. Methyllithium in diethyl ether was
purchased from Kanto Chemical Co., Inc. Triethylamine, carbon
tetrachloride, and dichloromethane were distilled under a nitrogen
atmosphere over calcium hydride. THF and Et2O were distilled
under a nitrogen atmosphere over sodium diphenylketyl. All reac-
tions were carried out under an inert atmosphere.
Analogous to the reaction modes of the [(allyloxy)silyl]lithi-
ums 1, two reaction modes would also be expected for the si-
lyllithium 12. If 12 undergoes the intramolecular nucleophilic
attack on the external carbon C(3) in the acetylene (mode a in
Scheme 6), the [2,3]-sila-Wittig rearrangement21 would pro-
ceed to give the lithium allenylsilanolate 15 and eventually
14. This is the case of the Hex-substituted substrate (7b). On
the other hand, if the silyllithium 12 experiences the intramo-
lecular nucleophilic attack on the internal carbon C(2) in the
acetylene (mode b in Scheme 6), the 4-exo-dig cyclization
would produce a vinyllithium containing an oxasilacyclobutyl-
idene moiety 16 as the most probable intermediate.22 Although
the 4-exo-dig cyclization is less favored according to the
Baldwin rules,12 the longer Si–C and Si–O bonds may reduce
the steric strain in the transition state and/or the product and
may allow the cyclization.23 In the next step, contrary to the
behavior of 11, 16 cannot easily cyclize to the three-membered
ring via the 1,3-cycloelimination due to the rigidity of the exo-
cyclic C–C double bond skeleton. Alternatively, the nucleo-
philic attack by another molecule of MeLi on the electrophilic
silicon atom cleaves the Si–O bond in 16, resulting in the for-
mation of 17 that contains the methyl-silylated vinyllithium
and allyloxylithium moieties.
Preparation of Propargyl Alcohols 8. 3-Decyn-2-ol (8b), 4-
phenyl-3-butyn-2-ol (8c), 4-(5-trimethylsilyl-2-thienyl)-3-butyn-
2-ol (8d), 4-trimethylsilyl-3-butyn-2-ol (8e), and 4-triphenyl-
silyl-3-butyn-2-ol (8f) were prepared from 3-butyn-2-ol (8a)
according to the literature procedures.10
Preparation of Allyl Alcohols 6. (E)-3-decen-2-ol (6b), (E)-
4-(5-trimethylsilyl-2-thienyl)-3-buten-2-ol (6d), (E)-4-trimethyl-
silyl-3-buten-2-ol (6e), and (E)-4-triphenylsilyl-3-buten-2-ol (6f)
were prepared by reduction of the corresponding propargyl alco-
hols 8 (see above) with Red-Al according to the literature proce-
dures.10 (E)-4-phenyl-3-buten-2-ol (6c) was prepared by the reac-
tion of (E)-3-phenyl-2-propenal with methyllithium.
A Typical Procedure for Preparation of [(Allyloxy)silyl]-
stannanes 4 and [(Propargyloxy)silyl]stannanes 7. Synthesis
of (E)-[(3-Buten-2-oxy)dimesitylsilyl]trimethylstannane (4a):
3-Buten-2-ol (6a) (0.35 mL, 2.5 mmol), 4-(dimethylamino)pyri-
dine (98 mg, 0.80 mmol), and triethylamine (1.1 mL, 8.0 mmol)
were added to a THF (8 mL) solution of (chlorodimesitylsilyl)tri-
methylstannane (5), prepared by the reaction of (dimesitylsilyl)tri-
methylstannane (1.86 g, 4.0 mmol) and carbon tetrachloride (8
mL). The reaction mixture was stirred at 60 ꢁC for 18 h. The vola-
tile materials were evaporated and the residue was diluted with
hexane (20 mL). The resulting salts were removed by filtration
and the filter cake was washed with hexane (30 mL). The filtrate
was concentrated and the residue (2.32 g) was subjected to column
chromatography on silica gel eluted with hexane/AcOEt (100/1)
(Rf ¼ 0:52) to give 4a (1.04 g, 78% yield) as a colorless oil. 4a;
1H NMR (CDCl3): ꢁ 0.06 (s, 9H), 1.14 (d, J ¼ 6:0 Hz, 3H), 2.23
(s, 3H), 2.24 (s, 3H), 2.27 (s, 6H), 2.30 (s, 6H), 4.10 (dq, J ¼ 6:0
and 6.0 Hz, 1H), 4.92 (dq, J ¼ 10:5 and 1.2 Hz, 1H), 4.95 (dt, J ¼
17:1 and 1.2 Hz, 1H), 5.79 (ddd, J ¼ 17:1, 10.5, and 6.0 Hz, 1H),
6.72 (s, 2H), 6.74 (s, 2H). 13C NMR (CDCl3): ꢁ ꢂ8:42, 21.17,
23.88, 23.97, 72.10, 113.43, 128.83, 128.90, 128.93, 133.11,
133.29, 138.36, 138.67, 142.15, 142.72, 142.79, 143.05. MS
(EI): m=z 502 (Mþ), 487, 447, 445, 373, 371, 337, 283, 217,
163. Anal. Calcd for C25H38OSiSn: C, 59.89; H, 7.64%. Found:
C, 59.61; H, 7.79%.
In the propargyloxy system, the silyl anion in 12 generally
prefers the nucleophilic attack on C(2) rather than on C(3),
which induces the 4-exo-dig cyclization. This regioselectivity
is rationalized by considering that the approach of the anionic
silicon center to the near carbon C(2) of the linear triple bond
may be more energetically favored than the approach to the
distant carbon C(3). To the best of our knowledge, no analo-
gous 4-exo-dig cyclization has been reported for the carbanion
counterparts, i.e., the propargyloxy-alkyllithiums. The unique
reaction mode in our silicon case may be due to the flexibility
ꢀ
of the silicon compounds with longer Si–C (1.87 A) and Si–O
ꢀ
ꢀ
(1.51 A) bonds compared to the C–C (1.54 A) and C–O (1.43
24
ꢀ
A) bonds.
Conclusion
The [(allyloxy)silyl]lithiums bearing the H, Hex, or Me3Si
substituent undergo the [2,3]-sila-Wittig rearrangement to af-
ford the allylsilanols. On the other hand, the [(allyloxy)silyl]-
lithiums bearing the Ph, Th, or Ph3Si substituent experience
the 4-exo-trig cyclization, followed by the 1,3-cycloelimina-
tion, to give the cyclopropylsilanols. Thus two different types
of compounds can be prepared from similar [(allyloxy)silyl]-
lithiums only by changing the substituent at the terminus of
the olefin. The two different reaction modes were determined
by the regioselection in the intramolecular reaction of the silyl-
lithium with the olefin during the initial step. In the [(propar-
gyloxy)silyl]lithiums, the unique 4-exo-dig cyclization is fa-
vored over the [2,3]-sila-Wittig rearrangement in all cases.
This may depend on the distance between the silyl anion center
and the reaction sites in the acetylenes.
Experimental
The 1H (270 MHz), 13C (67.94 MHz), and 29Si (53.67 MHz)
NMR spectra were recorded using a JEOL EX-270 spectrometer.
The 1H (300 MHz) and 13C (75.4 MHz) NMR spectra were re-
corded on a Varian Mercury 300 spectrometer. 1H and 13C chemi-
(E)-[(3-Decen-2-oxy)dimesitylsilyl]trimethylstannane (4b):

1524 Bull. Chem. Soc. Jpn., 78, No. 8 (2005)
Intramolecular Reactions of Silyllithiums
1H NMR (C6D6): ꢁ 0.35 (s, 9H), 0.94 (t, J ¼ 6:6 Hz, 3H), 1.22–
1.27 (m, 8H), 1.29 (d, J ¼ 6:0 Hz, 3H), 1.89–2.00 (m, 2H), 2.16
(s, 6H), 2.54 (s, 12H), 4.31 (dq, J ¼ 6:6 and 6.3 Hz, 1H), 5.40
(dt, J ¼ 15:0 and 6.3 Hz, 1H), 5.55 (dd, J ¼ 15:0 and 7.2 Hz,
1H), 6.77 (s, 4H). 13C NMR (C6D6): ꢁ ꢂ8:44, 14.29, 21.07,
22.99, 24.17, 24.62, 29.24, 29.37, 32.06, 32.48, 72.58, 129.69,
130.55, 133.77, 134.15, 134.43, 138.84, 139.09, 143.06, 143.35
(Although there should be 10 peaks of the sp2 carbons, only 9
peaks were observed). MS (EI): m=z 586 (Mþ), 571, 451, 447,
421, 283. Anal. Calcd for C31H50OSiSn: C, 63.53; H, 8.71%.
Found: C, 63.59; H, 8.61%.
447, 419, 376, 375, 283, 273, 163, 119. Anal. Calcd for
C31H48OSiSn: C, 63.81; H, 8.29%. Found: C, 63.75; H, 8.28%.
[(4-Phenyl-3-butyn-2-oxy)dimesitylsilyl]trimethylstannane
(7c): 1H NMR (C6D6): ꢁ 0.37 (s, 9H), 1.50 (d, J ¼ 6:3 Hz, 3H),
2.13 (s, 3H), 2.15 (s, 3H), 2.56 (s, 12H), 4.76 (d, J ¼ 6:3 Hz, 3H),
6.75 (s, 2H), 6.77 (s, 4H), 6.98–7.05 (m, 3H), 7.39–7.43 (m, 2H).
13C NMR (CDCl3): ꢁ ꢂ8:45, 21.14, 21.17, 23.92, 23.95, 25.28,
60.78, 83.66, 91.38, 122.96, 127.93, 127.96, 131.58, 132.78,
132.92, 138.51, 138.79, 142.97, 143.18. MS (EI): m=z 576
(Mþ), 561, 447, 411, 368, 367, 283, 265, 239, 163, 119. Anal.
Calcd for C31H40OSiSn: C, 64.70; H, 7.01%. Found: C, 64.80;
H, 7.11%.
(E)-[(4-Phenyl-3-buten-2-oxy)dimesitylsilyl]trimethylstan-
nane (4c): 1H NMR (C6D6): ꢁ 0.30 (s, 9H), 1.32 (d, J ¼ 6:3 Hz,
3H), 2.13 (s, 3H), 2.16 (s, 3H), 2.51 (s, 6H), 2.52 (s, 6H), 4.42 (dq,
J ¼ 6:3 and 6.3 Hz, 1H), 6.15 (dd, J ¼ 16:2 and 6.3 Hz, 1H), 6.25
(d, J ¼ 16:2 Hz, 1H), 6.73 (s, 2H), 6.78 (s, 2H), 7.07–7.22 (m,
5H). 13C NMR (CDCl3): ꢁ ꢂ8:70, 21.01, 21.06, 23.79, 23.83,
24.21, 72.08, 126.38, 127.30, 128.34, 129.00, 129.06, 133.15,
133.52, 133.71, 136.82, 138.53, 138.72, 142.80, 143.07, 143.13.
MS (EI): m=z 578 (Mþ), 563, 447, 413, 283, 163, 131. Anal. Calcd
for C31H42OSiSn: C, 64.48; H, 7.33%. Found: C, 64.32; H, 7.40%.
(E)-{[(5-Trimethylsilyl-2-thienyl)-3-buten-2-oxy]dimesityl-
silyl}trimethylstannane (4d): 1H NMR (C6D6): ꢁ 0.27 (s, 9H),
0.32 (s, 9H), 1.27 (d, J ¼ 6:4 Hz, 3H), 1.58 (s, 3H), 2.14 (s, 6H),
2.52 (s, 12H), 4.36 (dq, J ¼ 6:4 and 6.4 Hz, 1H), 6.17 (dd, J ¼
15:6 and 6.4 Hz, 1H), 6.43 (d, J ¼ 15:6 Hz, 1H), 6.74 (s, 2H),
6.77 (s, 2H), 6.89 (d, J ¼ 3:3 Hz, 1H), 7.03 (d, J ¼ 3:3 Hz,
1H). 13C NMR (C6D6): ꢁ ꢂ8:22, 0.04, 21.27, 24.35, 24.40,
72.32, 122.93, 127.23, 129.70, 129.76, 133.50, 133.66, 133.96,
134.66, 138.91, 139.12, 139.34, 142.97, 143.34, 147.55. MS
(EI): m=z 656 (Mþ), 491, 447, 407, 283, 73. Anal. Calcd for
C32H48OSSi2Sn: C, 58.62; H, 7.38%. Found: C, 58.69; H, 7.37%.
(E)-[(4-Trimethylsilyl-3-buten-2-oxy)dimesitylsilyl]trimeth-
ylstannane (4e): 1H NMR (C6D6): ꢁ 0.10 (s, 9H), 0.33 (s, 9H),
1.24 (d, J ¼ 6:3, 3H), 2.14 (s, 6H), 2.52 (s, 12H), 4.34 (dq, J ¼
6:3 and 1.2 Hz, 1H), 5.74 (dd, J ¼ 19:0 and 1.2 Hz, 1H), 6.11
(dd, J ¼ 19:0 and 6.7 Hz, 1H), 6.75 (s, 2H), 6.76 (s, 2H).
13C NMR (CDCl3): ꢁ ꢂ8:52, ꢂ0:01, 21.14, 21.17, 23.92, 23.95,
24.20, 71.67, 121.99, 126.51, 128.95, 129.00, 133.08, 133.44,
133.49, 134.05, 138.44, 138.64, 139.17, 142.69, 143.00, 147.03.
MS (EI): m=z 574 (Mþ), 559, 409, 283, 217, 163, 119. Anal. Calcd
for C28H46OSi2Sn: C, 58.64; H, 8.08%. Found: C, 58.72; H,
8.11%.
[(5-Trimethylsilyl-3-butyn-2-oxy)dimesitylsilyl]trimethyl-
stannane (7e): 1H NMR (C6D6): ꢁ 0.20 (s, 9H), 0.38 (s, 9H),
1.40 (d, J ¼ 6:3 Hz, 3H), 2.13 (s, 3H), 2.14 (s, 3H), 2.53 (s,
6H), 2.54 (s, 6H), 4.54, (q, J ¼ 6:3 Hz, 1H), 6.75 (s, 2H), 6.76
(s, 2H). 13C NMR (CDCl3): ꢁ ꢂ8:45, ꢂ0:03, 21.15, 23.93,
23.97, 25.15, 60.71, 87.56, 107.71, 128.93, 132.68, 132.80,
138.51, 138.76, 142.92, 143.10. MS (EI): m=z 572 (Mþ), 557,
447, 407, 363, 335, 283, 261. Anal. Calcd for C28H44OSi2Sn: C,
58.84; H, 7.76%. Found: C, 59.07; H, 8.04%.
[(4-Triphenylsilyl-3-butyn-2-oxy)dimesitylsilyl]trimethyl-
stannane (7f): 1H NMR (C6D6): ꢁ 0.29 (s, 9H), 1.40 (d, J ¼ 6:6
Hz, 3H), 2.11 (s, 3H), 2.13 (s, 3H), 2.50 (s, 6H), 2.51 (s, 6H), 4.63,
(q, J ¼ 6:6 Hz, 1H), 6.71 (s, 2H), 6.73 (s, 2H), 7.22–7.24 (m, 9H),
7.79–7.83 (m, 6H). 13C NMR (CDCl3): ꢁ ꢂ8:63, 21.18, 23.92,
23.97, 25.20, 61.01, 82.66, 112.31, 127.73, 128.98, 129.69,
132.27, 133.31, 135.47, 138.71, 142.90, 143.05. MS (EI): m=z
742 (Mþ), 641, 549, 447, 283, 209, 163, 73. Anal. Calcd for
C43H50OSi2Sn: C, 68.16; H, 6.65%. Found: C, 67.94; H, 6.67%.
Typical Procedure for the [2,3]-Sila-Wittig Rearrangement.
Synthesis of (E)-(2-Buten-1-yl)dimesitylsilanol (9a): A solu-
tion of n-BuLi in hexane (1.6 M, 0.63 mL, 1.0 mmol) was added
dropwise to a solution of 4a (251 mg, 0.50 mmol) in THF (1.0
mL) at 0 ꢁC and the reaction mixture was stirred for 3 h at 0
ꢁC. A 5% aq solution of NH4Cl (1.0 mL) was added to the reac-
tion mixture at 0 ꢁC. The mixture was extracted with Et2O
(10 mL ꢃ 3) and the combined organic layer was dried over anhy-
drous MgSO4. The solution was concentrated in vacuo and the
residue was subjected to column chromatography on silica gel
(40 mL) eluted with hexane/AcOEt (20/1) (Rf ¼ 0:25) to give
1
9a (146 mg, 86% yield) as a colorless oil. 9a; H NMR (C6D6):
ꢁ 1.56 (d, J ¼ 6:9 Hz, 3H), 1.84 (s, 1H), 2.14 (s, 6H), 2.18 (dd,
J ¼ 5:7 and 1.2 Hz, 2H), 2.43 (s, 12H), 5.22–5.53 (m, 2H), 6.75
(s, 4H). 13C NMR (CDCl3): ꢁ 18.17, 21.09, 23.67, 27.68,
125.72, 126.40, 129.02, 132.88, 138.81, 143.27. MS (EI): m=z
338 (Mþ), 283, 163. Anal. Calcd for C22H30OSi: C, 78.05; H,
8.93%. Found: C, 78.13; H, 9.04%.
(E)-(2-Decen-4-yl)dimesitylsilanol (9b): 1H NMR (C6D6): ꢁ
0.92 (t, J ¼ 6:6 Hz, 3H), 1.22–1.42 (m, 7H), 1.59 (d, J ¼ 6:0 Hz,
3H), 1.60–1.76 (m, 3H), 1.84–1.96 (m, 1H), 2.15 (s, 6H), 2.34 (t,
J ¼ 9:9 Hz, 1H), 2.51 (s, 6H), 2.52 (s, 6H), 5.34 (dq, J ¼ 15:3 and
6.0 Hz, 1H), 5.49 (dd, J ¼ 15:3 and 9.0 Hz, 1H), 6.77 (s, 4H).
13C NMR (CDCl3): ꢁ 14.18, 18.32, 21.04, 22.75, 23.69, 23.82,
28.90, 29.20, 29.32, 31.87, 36.72, 42.30, 124.59, 128.97, 129.15,
131.89, 132.92, 133.24, 138.50, 138.55, 143.31, 143.53. MS
(EI): m=z 421 (Mþ), 283, 163. Anal. Calcd for C28H42OSi: C,
79.56; H, 10.01%. Found: C, 79.47; H, 10.06%.
(E)-[(4-Triphenylsilyl-3-buten-2-oxy)dimesitylsilyl]trimeth-
ylstannane (4f): 1H NMR (C6D6): ꢁ 0.28 (s, 9H), 1.18 (d, J ¼
6:3 Hz, 3H), 2.12 (s, 3H), 2.13 (s, 3H), 2.47 (s, 6H), 2.48 (s,
6H), 4.45 (dt, J ¼ 6:3 and 4.2 Hz, 1H), 6.33 (dd, J ¼ 18:6 and
4.2 Hz, 1H), 6.41 (d, J ¼ 18:6 Hz, 1H), 6.70 (s, 2H), 6.74 (s,
2H), 7.22–7.26 (m, 9H), 7.61–7.65 (m, 6H). 13C NMR (CDCl3):
ꢁ ꢂ8:50, 21.15, 23.57, 23.97, 24.00, 74.10, 121.10, 127.63,
128.93, 128.97, 129.30, 133.34, 133.44, 134.36, 135.81, 138.48,
142.71, 142.76, 155.21. MS (EI): m=z 758 (Mþ), 744, 595, 549,
283, 259. Anal. Calcd for C43H52OSi2Sn: C, 67.98; H, 6.90%.
Found: C, 68.15; H, 6.97%.
[(3-Decyn-2-oxy)dimesitylsilyl]trimethylstannane
(7b):
1H NMR (C6D6): ꢁ 0.40 (s, 9H), 0.91 (t, J ¼ 6:3 Hz, 3H), 1.15–
1.44 (m, 8H), 1.46 (d, J ¼ 6:3 Hz, 3H), 2.07 (dt, J ¼ 7:2 and
1.2 Hz, 2H), 2.14 (s, 3H), 2.15 (s, 3H), 2.56 (s, 12H), 4.60 (q, J ¼
6:3 Hz, 1H), 6.77 (s, 2H), 6.78 (s, 2H). 13C NMR (CDCl3): ꢁ
ꢂ8:46, 14.18, 18.93, 21.15, 22.66, 23.90, 23.95, 25.63, 28.64,
31.45, 60.53, 82.24, 84.24, 128.91, 132.91, 133.04, 138.35,
138.68, 142.90, 143.17. MS (EI): m=z 584 (Mþ), 569, 567, 487,
(E)-(4-Trimethylsilyl-2-buten-4-yl)dimesitylsilanol
(9e):
1H NMR (C6D6): ꢁ 0.19 (s, 9H), 1.59 (d, J ¼ 6:0 Hz, 3H),
1.60–1.76 (m, 3H), 1.61 (d, J ¼ 6:3 Hz, 3H), 1.74 (brs, 1H),
1.84–1.96 (m, 1H), 2.15 (s, 6H), 2.34 (t, J ¼ 9:9 Hz, 1H), 2.51

A. Kawachi et al.
Bull. Chem. Soc. Jpn., 78, No. 8 (2005) 1525
(s, 6H), 2.52 (s, 6H), 5.34 (dq, J ¼ 15:3 and 6.0 Hz, 1H), 5.49 (dd,
J ¼ 15:3 and 9.0 Hz, 1H), 6.77 (s, 4H). 13C NMR (CDCl3): ꢁ
ꢂ0:13, 18.37, 21.00, 21.04, 23.55, 24.01, 27.88, 124.11, 127.98,
129.13, 129.43, 134.03, 134.13, 138.38, 138.61, 143.33, 143.45.
MS (EI): m=z 410 (Mþ), 395, 320, 283, 163. Anal. Calcd for
C25H38OSi2: C, 73.10; H, 9.33%. Found: C, 73.15; H, 9.33%.
Typical Procedure for Cyclopropylsilane Synthesis. Syn-
thesis of (2-Triphenylsilyl-3-methylcyclopropan-1-yl)dimesi-
tylsilanol (10f): A solution of n-BuLi in hexane (1.6 M, 0.38
mL, 0.60 mmol) was added dropwise to a solution of 7f (380
mg, 0.50 mmol) in THF (1.0 mL) at 0 ꢁC and the reaction mixture
was stirred for 3 h. A 5% aq solution of NH4Cl (1.0 mL) was add-
ed to the reaction mixture at 0 ꢁC. The mixture was extracted with
Et2O (10 mL ꢃ 3) and the combined organic layer was dried over
MgSO4. The solution was concentrated in vacuo and the residue
was subjected to column chromatography on silica gel (50 mL)
eluted with hexane/AcOEt (20/1) (Rf ¼ 0:23) to give 10f (210
mg, 71% yield) as a colorless oil. 10f: 1H NMR (C6D6): ꢁ 0.54
(dd, Jab ¼ 7:8 and Jac ¼ 7:8 Hz, 1H), 0.92 (dd, Jbc ¼ 8:7 and
Jab ¼ 7:8 Hz, 1H), 1.17 (d, Jcd ¼ 6:0 Hz, 3H), 1.44 (s, 1H),
1.54–1.61 (m, 1H), 2.13 (s, 3H), 2.18 (s, 3H), 2.43 (s, 6H), 2.45
(s, 6H), 6.72 (s, 2H), 6.76 (s, 2H), 7.18–7.22 (m, 9H), 7.67–7.70
(m, 6H) (Chart 2). 13C NMR (CDCl3): ꢁ 6.52, 16.21, 17.58,
21.07, 21.15, 127.57, 128.95, 129.06, 131.76, 133.00, 135.40,
135.88, 138.53, 138.91, 143.17, 143.78. MS (EI): m=z 596
(Mþ), 541, 476, 421, 283, 259. Anal. Calcd for C44H44OSi2: C,
80.48; H, 7.43%. Found: C, 80.41; H, 7.65%.
NOE
13%
δ 0.92
J
J
bc = 8.7 and
ab = 7.8 Hz
11%
Mes
Hc δ 1.54 - 1.61
Hb
Mes Si OH
8% 2%
2%
CHd
Ph3Si
δ 1.17
3
6%
Ha
2%
(Jcd = 6.0 Hz)
1%
δ 0.54
Jab = 7.8 and
Jac = 7.8 Hz
10f
Chart 2.
Hc δ 1.32 - 1.41
Hb
Ph
Mes
δ 2.41
J
J
bc = 8.7 and
Mes Si OH
ab = 7.1 Hz
CHd
3
Ha
δ 0.98
(Jcd = 6.0 Hz)
δ 0.68
Jab = 7.1 and
10c
J
ac = 7.1 Hz
Chart 3.
(3-Methyl-2-phenylcyclopropan-1-yl)dimesitylsilanol (10c):
1H NMR (C6D6): ꢁ 0.68 (dd, Jab ¼ 7:1 and Jac ¼ 7:1 Hz, 1H),
0.98 (d, Jcd ¼ 6:0 Hz, 3H), 1.32–1.41 (m, 1H), 1.49 (s, 1H),
2.15 (s, 3H), 2.16 (s, 3H), 2.41 (dd, Jbc ¼ 8:7 and Jab ¼ 7:1 Hz,
1H), 2.50 (s, 6H), 2.52 (s, 6H), 6.76 (s, 2H), 6.78 (s, 2H), 7.08–
7.17 (m, 5H) (Chart 3). 13C NMR (CDCl3): ꢁ 14.27, 16.34,
18.44, 21.01, 23.78, 26.60, 125.62, 127.82, 129.06, 129.09,
132.20, 132.79, 138.90, 139.01, 139.48, 143.49, 143.68 (Although
there should be 12 peaks of the sp2 carbons, only 11 peaks were
observed). MS (EI): m=z 414 (Mþ), 323, 296, 283, 163. Anal.
Calcd for C28H34OSi: C, 81.10; H, 8.26%. Found: C, 81.04; H,
8.49%.
NOE
13%
Mes
δ 2.42 - 2.57
Hc
8%
Hb
δ 1.32 - 1.42
Mes Si OH
2%
CHd
δ 1.13
3
8%
Ha
S
(Jcd = 6.0 Hz)
3%
δ 0.74
Me3Si
Jab = 7.2 and
[3-Methyl-2-(5-trimethylsilyl-2-thienyl)cyclopropan-1-yl]di-
mesitylsilanol (10d): 1H NMR (C6D6): ꢁ 0.28 (s, 9H), 0.74 (dd,
Jab ¼ 7:2 and Jac ¼ 7:2 Hz, 1H), 1.13 (d, Jcd ¼ 6:0 Hz, 3H), 1.32–
1.42 (m, 1H), 1.58 (s, 1H), 2.14 (s, 3H), 2.15 (s, 3H), 2.42–2.57
(m, 1H), 2.49 (s, 6H), 2.51 (s, 6H), 6.74 (s, 2H), 6.75 (s, 2H),
6.83 (d, J ¼ 3:0 Hz, 1H), 7.08 (d, J ¼ 3:0 Hz, 1H) (Chart 4).
13C NMR (67.9 MHz, CDCl3): ꢁ 0.11, 14.55, 19.42, 20.33,
21.14, 21.65, 23.92, 23.97, 126.40, 129.03, 131.68, 132.29,
133.59, 137.80, 138.92, 138.99, 143.41, 143.55, 149.63. MS
(EI): m=z 492 (Mþ), 477, 283. HRMS (EI): Calcd for
C29H40OSSi2: m=z 492.2338. Found: m=z 492.2338.
J
ac = 7.2 Hz
10d
Chart 4.
(E)-(2-Hydroxy-3-decen-3-yl)dimesitylmethylsilane (13b):
1H NMR (C6D6): ꢁ 0.89 (t, J ¼ 6:7 Hz, 3H), 0.99 (s, 3H), 1.18–
1.25 (m, 10H), 1.31 (d, J ¼ 6:5 Hz, 3H), 2.16 (s, 6H þ 1H),
2.42 (s, 6H), 2.46 (s, 6H), 4.42–4.50 (m, 1H), 6.50 (t, J ¼ 7:0
Hz, 1H), 7.28 (s, 4H). 13C NMR (CDCl3): ꢁ 14.14, 21.00, 22.65,
23.93, 24.76, 24.85, 29.28, 29.31, 31.77, 32.92, 70.48, 129.28,
129.31, 134.19, 134.26, 138.16, 138.20, 143.73, 144.20, 144.24,
145.09. MS (EI): m=z 436 (Mþ), 421, 418, 316, 281, 179. HRMS
(EI): Calcd for C29H44OSi: m=z 436.3136. Found: m=z 436.3150.
Typical Procedure for Intramolecular Reaction of (Pro-
pargyloxysilyl)stannanes. Reaction of 7b with MeLi: A solu-
tion of MeLi in Et2O (1.14 M, 0.88 mL, 1.0 mmol) was added
dropwise to a solution of 7b (292 mg, 0.50 mmol) in THF (1.0
(1-Hexyl-3-methylallen-1-yl)dimesitylsilanol
(14b):
1H NMR (C6D6): ꢁ 0.91 (t, J ¼ 7:2 Hz, 3H), 1.20–1.50 (m, 9H),
1.60–1.75 (m, 2H), 2.16 (s, 6H), 2.20–2.35 (m, 2H), 2.54 (s,
6H), 2.55 (s, 6H), 4.70–4.83 (m, 1H), 6.79 (s, 4H). 13C NMR
(C6D6): ꢁ 13.10, 14.51, 21.28, 23.24, 24.30, 24.36, 29.62, 29.81,
29.95, 32.34, 82.33, 99.31, 129.53, 129.54, 133.49, 133.52,
138.88, 138.97, 144.08, 144.11, 208.82. MS (EI): m=z 420
(Mþ), 283, 163. HRMS (EI): Calcd for C28H40OSi: m=z
420.2848. Found: m=z 420.2852.
ꢁ
mL) at 0 C and the reaction mixture was stirred for 3 h. A 5%
aq solution of NH4Cl (1.0 mL) was added to the reaction mixture
at 0 ꢁC. The mixture was extracted with Et2O (10 mL ꢃ 3) and the
combined organic layer was dried over anhydrous MgSO4. The
solution was concentrated in vacuo and the residue was subjected
to column chromatography on silica gel (40 mL) eluted with hex-
ane/AcOEt (40/1) to give 13b (90 mg, 41% yield) (Rf ¼ 0:12)
and 14b (80 mg, 38% yield) (Rf ¼ 0:27) as colorless oils.
(E)-(2-Hydroxy-4-phenyl-3-buten-3-yl)dimesitylmethylsilane

1526 Bull. Chem. Soc. Jpn., 78, No. 8 (2005)
Intramolecular Reactions of Silyllithiums
(13c): 1H NMR (C6D6): ꢁ 0.58 (s, 3H), 1.32 (d, J ¼ 6:9 Hz, 3H),
1.46 (d, J ¼ 5:4 Hz, 1H), 2.15 (s, 6H), 2.35 (s, 6H), 2.50 (s, 6H),
4.64 (dq, J ¼ 6:9 and 5.4 Hz, 1H), 6.78 (s, 2H), 6.80 (s, 2H),
6.97–7.00 (m, 3H), 7.37–7.40 (m, 2H), 7.69 (s, 1H). 13C NMR
(CDCl3): ꢁ 6.85, 21.07, 24.01, 24.79, 70.86, 127.16, 127.81,
128.60, 129.41, 129.59, 134.21, 135.00, 138.39, 138.53, 139.07,
141.87, 143.97, 144.09, 149.42. MS (EI): m=z 428 (Mþ), 410,
395, 383, 308, 281. HRMS (EI): Calcd for C29H36OSi: m=z
428.2535. Found, m=z 428.2507.
Chem. Soc., 122, 412 (2000). g) M. J. Mealy and W. F. Bailey,
J. Organomet. Chem., 646, 59 (2002).
3
For reviews of silyl anions: a) K. Tamao and A. Kawachi,
Adv. Organomet. Chem., 38, 1 (1995). b) P. D. Lickiss and C. M.
Smith, Coord. Chem. Rev., 145, 75 (1995). c) J. Belzner and U.
Dehnert, ‘‘The Chemistry of Organic Silicon Compounds,’’ ed
by Z. Rappoport and Y. Apeloig, John-Wiley & Sons, Chichester
(1998), Vol. 2, pp. 779–826.
4
a) Review: A. Kawachi and K. Tamao, Bull. Chem. Soc.
(E)-(2-Hydroxy-4-trimethylsilyl-3-buten-3-yl)dimesitylmeth-
ylsilane (13e): 1H NMR (C6D6): ꢁ 0.19 (s, 9H), 1.03 (s, 3H),
1.21 (d, J ¼ 6:3 Hz, 3H), 1.38 (d, J ¼ 5:7 Hz, 1H), 2.14 (s,
3H), 2.15 (s, 3H), 2.38 (s, 6H), 2.44 (s, 6H), 4.53 (dq, J ¼ 6:3
and 5.7 Hz, 1H), 6.78 (s, 4H), 7.03 (s, 1H). 13C NMR (C6D6): ꢁ
0.95, 8.85, 21.18, 24.47, 25.52, 25.79, 73.04, 129.94, 129.98,
134.73, 135.17, 138.59, 138.62, 143.26, 144.57, 144.62, 168.92.
MS (EI): m=z 424 (Mþ), 408, 281, 179. HRMS (EI): Calcd for
C26H40OSi2: m=z 424.2618. Found: m=z 424.2638.
(E)-(2-Hydroxy-4-triphenylsilyl-3-buten-3-yl)dimesitylmeth-
ylsilane (13f): 1H NMR (C6D6): ꢁ 0.33 (s, 3H), 1.25 (d, J ¼ 6:3
Hz, 3H), 1.54 (d, J ¼ 5:4 Hz, 1H), 2.14 (s, 3H), 2.15 (s, 3H), 2.34
(s, 6H), 2.37 (s, 6H), 4.72 (dq, J ¼ 6:3 and 5.4 Hz, 1H), 6.70 (s,
2H), 6.73 (s, 2H), 7.09–7.27 (m, 9H), 7.77–7.80 (m, 6H), 7.85 (s,
1H). 13C NMR (CDCl3): ꢁ 7.41, 21.04, 24.57, 25.12, 25.27, 73.53,
127.55, 129.13, 129.26, 129.33, 133.72, 134.86, 135.07, 135.84,
138.07, 138.27, 143.89, 144.20, 172.75. MS (EI): m=z 608
(Mþ), 592, 281, 259. Anal. Calcd for C41H46OSi2: C, 80.60; H,
7.59%. Found: C, 80.41; H, 7.65%.
Jpn., 70, 945 (1997). b) A. Kawachi, Y. Oishi, T. Kataoka, and
K. Tamao, Organometallics, 23, 2949 (2004), and references cited
therein.
5
a) A. Kawachi, N. Doi, and K. Tamao, J. Am. Chem. Soc.,
119, 233 (1997). b) A. Kawachi, H. Maeda, H. Nakumura, N. Doi,
and K. Tamao, J. Am. Chem. Soc., 123, 3143 (2001).
6 The terms ‘‘prim-, sec-, and tert-allyloxy’’ mean that the
allylic carbon is primary, secondary, and tertiary, respectively.
7
1216.
8
A. Kawachi, H. Maeda, and K. Tamao, Chem. Lett., 2000,
Although we tentatively called this reaction ‘‘cyclopropa-
nation’’ in previous papers,5b,7 the use of this term does not seem
to be appropriate since the term has been used almost only for the
cyclopropanation reactions of olefins with carbenes or carbenoids.
9
and 7.
Part of the results has already been presented in Refs. 5b
10 The sec-allyl alcohols and sec-propargyl alcohols were
prepared according to the procedures in the literature: a) S. E.
Denmark and S. P. O’Connor, J. Org. Chem., 62, 584 (1997). b)
K. Sonogashira, Y. Tobita, and N. Hagihara, Tetrahedron Lett.,
50, 4467 (1975). c) L. Brandsma, ‘‘Preparative Acetylene
Chemistry,’’ 2nd ed, Elsevier (1998). d) S. K. Chaudhary and O.
Hemandez, Tetrahedron Lett., 2, 99 (1979). e) E. J. Corey and
A. Venkateswarlu, J. Am. Chem. Soc., 94, 6190 (1972).
11 a) Y.-D. Wu, K. N. Houk, and J. A. Marshall, J. Org.
Chem., 55, 1421 (1990). b) K. Mikami, T. Uchida, T. Hirano,
Y.-D. Wu, and K. N. Houk, Tetrahedron, 50, 5917 (1994). c) T.
Okajima and Y. Fukazawa, Chem. Lett., 1997, 81.
We thank the Ministry of Education, Culture, Sports, Sci-
ence and Technology, Japan, for the Grants-in-Aid for COE
Research on Elements Science, No. 12CE2005, and for Scien-
tific Research Nos. 12042241 and 12750763. H. M. thanks the
Japan Society for the Promotion of Science (fellowship for
Japanese Junior Scientists).
Supporting Information
12 J. E. Baldwin, J. Chem. Soc., Chem. Commun., 1976, 734.
13 Recent examples of 1,3-cycloelimination: a) A. Krief and
M. Hobe, Tetrahedron Lett., 33, 6527 (1992). b) D. Hoppe, M.
Paetow, and F. Hintze, Angew. Chem., Int. Ed. Engl., 32, 394
(1993). c) K. Tomooka, N. Komine, T. Sasaki, H. Shimizu, and
T. Nakai, Tetrahedron Lett., 39, 9715 (1998). d) S. Norsikian, I.
Marek, S. Klein, J.-F. Poisson, and J. F. Normant, Chem.—Eur.
J., 5, 2055 (1999).
Summary schemes of the preparation of sec-allyl alcohols
(6a–f) and sec-propargyl alcohols (8b, c, e, and f). This material
is available free of charge on the web at: http://www.csj.jp/
journals/bcsj/.
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¨
20 Two molar amounts of MeLi were required to consume the
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