Geminal dimetalation of alkylidene-type carbenoids with silylboranes and diborons

Article abstract of DOI:10.1016/S0040-4020(02)00648-8

A novel and efficient method for gem-dimetalation of carbenoids has been demonstrated. Treatment of alkylidene-type lithium carbenoids with such an interelement compound as silylborane or diboron to generate the corresponding borate complex, followed by warming to room temperature, induced migration of the silyl or boryl group from a negatively charged boron atom to the carbenoid carbon to afford 1-boryl-1-silyl-1-alkenes or 1,1-diboryl-1-alkenes in good yields. Carbon-carbon bond forming transformations of the gem-dimetalated compounds mediated by boron or silicon is also described.

Full text of DOI:10.1016/S0040-4020(02)00648-8

Tetrahedron 58 (2002) 6381–6395
Geminal dimetalation of alkylidene-type carbenoids with
silylboranes and diborons
*
Takuya Kurahashi, Takeshi Hata, Hirokazu Masai, Hirotaka Kitagawa, Masaki Shimizu
*
and Tamejiro Hiyama
Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
Received 1 April 2002; revised 18 April 2002; accepted 22 April 2002
Dedicated to Professor Yoshito Kishi on the occasion of his receipt of the Tetrahedron Prize for Creativity in Organic Chemistry
Abstract—A novel and efficient method for gem-dimetalation of carbenoids has been demonstrated. Treatment of alkylidene-type lithium
carbenoids with such an interelement compound as silylborane or diboron to generate the corresponding borate complex, followed by
warming to room temperature, induced migration of the silyl or boryl group from a negatively charged boron atom to the carbenoid carbon
to afford 1-boryl-1-silyl-1-alkenes or 1,1-diboryl-1-alkenes in good yields. Carbon–carbon bond forming transformations of the
gem-dimetalated compounds mediated by boron or silicon is also described. q 2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
ethyl diazoacetate4 or isonitriles.5 In view of the growing
interest in gem-organodimetallics,1a,b novel and efficient
synthesis of gem-dimetallic compounds via gem-dimetala-
tion with interelement compounds should be of great
significance.
Much attention has been paid on organodimetallic com-
pounds in organic synthesis, because such bimetallic
compounds serve as versatile intermediates or reagents for
further elaborative transformations.1 In view of synthetic
methods for organodimetallic compounds, two strategies
are conceptually possible (Scheme 1). One is a stepwise
procedure involving initial preparation of an M1-containing
organometallic compound from an organic molecule and
metal M1, followed by introduction of another metal M2.
The other involves simultaneous introduction of two metals
into an organic molecule using an interelement compound
M1–M2.2 It is apparent that the second approach, if feasible,
is an attractive and straightforward method.
Ate-type carbenoids generated from gem-dihalo compounds
One of the examples categorized in the second approach is
transition metal-catalyzed vic-dimetalation of a carbon–
carbon unsaturated bond with such an interelement
compound as B–B, B–Si, B–Sn, Mg–Si, Mg–Zn, Mg–
Sn, Al–Si, Si–Si, Si–Sn, Ge–Ge, or Sn–Sn (Scheme 2).3
In sharp contrast, gem-dimetalation with interelement
compounds are limited to the reaction of silylborane with
Scheme 2. Examples of dimetalation with interelement compounds.
Scheme 1. Synthetic route to organodimetallic compounds.
Keywords: boron; carbenoids; metalation; silicon.
*
Corresponding authors. Tel.: þ81-75-753-5535; fax: þ81-75-753-5555;
e-mail: shimizu@npc05.kuic.kyoto-u.ac.jp
Scheme 3. 1,2-Migration of a carbonaceous substituent in an ate complex.
0040–4020/02/$ - see front matter q 2002 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(02)00648-8

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T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
cially or readily available, stable, and easy to handle.
Furthermore, the resulting products, 1-boryl-1-silyl-1-
alkenes8 or 1,1-diboryl-1-alkenes,9 should be potentially
valuable reagents for construction of complex carbon
framework in view that a variety of efficient transformations
using alkenylborane and -silane functionalities are
available.10,11 Herein we describe novel synthesis of
gem-dimetallic compounds by gem-silylborylation and
gem-diborylation of alkylidene-type lithium carbenoids
with silylboranes 1–5 and diborons 6–9, respectively
(Fig. 1).12 In addition, further transformations of the
silylborylated and diborylated compounds are disclosed.
Scheme 4. Synthetic strategy for the synthesis of gem-dimetalated
compounds from lithium carbenoids and interelement compounds.
by treatment with an ate complex or a combination of BuLi
and an organometallic reagent undergo 1,2-migration of a
carbonaceous substituent from the negatively charged metal
to the carbenoid carbon with inversion of configuration,
giving rise to homologated organometallic compounds
which can then react with an electrophile, all operations
being carried out in one pot (Scheme 3). Various kinds of
organometallic reagents are applicable to this type of
reaction.6
2. Results and discussion
2.1. gem-Silylborylation of alkylidene-type carbenoids
Silylboranes 1–5 were obtained as follows: (triphenyl-
silyl)(pinacolato)borane (1) and (methyldiphenylsilyl)(pina-
colato)borane (2), and (dimethylphenylsilyl)(pinacolato)-
borane (3) were prepared according to the procedure
reported previously.13 When we applied the procedure
to dimethylphenylsilyllithium and (þ)-(pinanediolato)-
borane,14 we obtained (dimethylphenylsilyl)((þ)-pinane-
diolato)borane (4) as a novel silylborane in 64% yield.
We envisioned that gem-dimetalation of carbenoids should
be realized if an ate complex possessing metal M2 as a
migrating group could be generated when an interelement
compound was applied to an alkylidene-type carbenoid
reagent (Scheme 4).7 We chose silylboranes and diborons as
the interelement compounds to be employed, because
various kinds of those dimetallic compounds are commer-
Figure 1. Silylboranes 1–5 and diborons 6–9.

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
Table 1. Reaction of 11a and 11b with silylboranes 1–5
6383
Entry
Silylborane
Carbenoid
Product
Yield (%)a
1
2
3
4
5
6
7
8
9
10
1
1
2
2
3
11a
11b
11a
11b
11a
11b
11a
11b
11a
11b
12a
12b
13a
13b
14a
14b
15a
15b
16a
16b
60
,1
62
,1
81
84
72
78
45
3
4
4
5b
5b
67
A mixture of 10a (0.50 mmol), THF (2 mL), and Et2O (1 mL) was treaed with LiTMP (0.50 mmol) and silylborane 1–5 (0.50 mmol) at 2108C for 10 min,
then gradually warmed to room temperature. Alternatively, a mixture of 10b (0.53 mmol), THF (2 mL), and Et2O (1 mL) was treated with BuLi (0.50 mmol)
and silylborane 1–5 (0.50 mmol) at 21108C for 10 min, then warmed to room temperature gradually.
a
Isolated yields based on silylborane 1–5 are given.
A 0.6 M solution in THF/HMPA (5:1) was used.
b
Similarly, we examined the preparation and isolation of
(trimethylsilyl)(pinacolato)borane (5). Although the for-
mation of 5 was reportedly suggested by GC–MS during the
Pt-catalyzed diboration of bis(trimethylsilyl)acetylene with
6,15 to our knowledge, no example involving the isolation
and use of 5 as a reagent is available. Accordingly, we
treated trimethylsilyllithium, generated from hexamethyl-
disilane and methyllithium in HMPA,16 with a THF solution
of (pinacolato)borane to confirm the formation of 5 by
GC–MS of the reaction mixture. However, attempted
purification of 5 by distillation, silica gel column chroma-
tography, or gel permeation chromatography resulted in the
decomposition of 5. Therefore, 5 was used as a THF/HMPA
(5:1) solution without further purification.
chromatography (entries 9 and 10). These results are the
first demonstration that 5 can be utilized as a reagent for the
synthesis of diorganometallics.
The best results obtained with 3 in hand, we next applied the
silylborylation to various kinds of carbenoids using 3. The
carbenoids were generated by halogen–lithium exchange,
and results are shown in Table 2. 2,2-Disubstituted
dibromoalkene 10c and dichloroalkene 10d afforded the
corresponding products 17 and 18 in 84 and 60% yields,
respectively (entries 1 and 2). Stereoselective gem-silyl-
borylation is possible, when an unsymmetrical alkylidene-
type carbenoid is generated stereoselectively. Thus, dibro-
moalkene 10e containing a 2-(methoxyethoxy)methoxy
group (MEMO group) was treated with 0.95–0.98 molar
amount of BuLi in Et2O at 21108C to produce a carbenoid
stereoselectively with the MEMO group and lithium being
cis.17 The carbenoid selectively reacted with 3 to give 19 as
a single diastereomer (entry 3). The stereochemical out-
come clearly demonstrates that lithium is first replaced by
boron and the subsequent anionic 1,2-migration induces
inversion of configuration to finally give rise to 19 (vide
infra).
Using 1-bromo-1-lithioethene (11a) and (1-bromo-1-lithio-
methylene)cyclohexane (11b) as a typical alkylidene-type
carbenoid, we first investigated the scope of silylboranes on
gem-silylborylation. Carbenoids 11a and 11b in THF were
treated with silylboranes 1–5 at 21108C, and the resulting
mixture was warmed to room temperature. The results are
summarized in Table 1. (Triphenylsilyl)borane 1 and
(methyldiphenylsilyl)borane 2 reacted with unsubstituted
carbenoid 11a to give the corresponding products 12a and
13a in moderate yields (entries 1 and 3), whereas
dimetalated products 12b and 13b were not obtained with
2,2-disubstiuted carbenoid 11b (entries 2 and 4). In contrast,
gem-silylborylation of 11a and 11b using (dimethylphenyl-
silyl)borane 3 or optically active silylborane 4 proceeded in
good yields, respectively (entries 5–8). These results
suggest that the relatively bulkier substituent on silicon
induces repulsion with substituents in a carbenoid and
probably prevents formation of a borate complex
or 1,2-migration of a silicon atom. Indeed, (trimethyl-
silyl)borane 5 that is less bulkier than 3 is also applicable to
this gem-silylborylation, although 16a and 16b slightly
decompose during purification by silica gel column
Lithium carbenoids generated by deprotonation of chloro-
alkenes with lithium 2,2,6,6-tetramethylpiperidide (LiTMP)
or BuLi could be also applied to the silylborylation (Table
3). As (E )-1,4-dihalo-2-butene is known to give predomi-
nantly (Z )-1-halobutadiene,18 dichlorobutene 10f was
treated with 2 equiv. of LiTMP at 2908C to give (Z )-1-
chloro-1-lithio-1,3-butadiene (11f) stereoselectively, which
was allowed to react with 3, affording (E )-gem-silylboryl-
ated product 20 in a good yield (Table 3). Conjugated
carbenoids 11g and 11h, generated from 10g and 10h,
respectively, were gem-silylborylated with 3 to give diene
21 and enyne 22. The stereochemistry of 21 was completely
controlled to be Z, whereas 22 was isolated as a

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T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
Table 2. gem-Silylborylation of alkylidene-type carbenoids generated by halogen–lithium exchange
Entry
1
Dihaloalkene
Product
Yield (%)a
84
2
60
45
3b
A mixture of 1,1-dihaloalkene 10c–10e (0.50 mmol), THF (2 mL), and Et2O (1 mL) was treated with BuLi (0.50 mmol) and 3 (0.50 mmol) at 21108C for
10 min, then gradually warmed to room temperature.
a
Isolated yields based on 3 are given.
Et2O (2 mL) was used as a solvent.
b
stereoisomeric mixture due probably to facile isomerization
of carbenoid 11h.
chemical transformations shown in Scheme 5: Pd-catalyzed
cross-coupling reaction of 19 and 21 with iodobenzene with
retention of configuration followed by protodesilylation
with Bu4NF (retention of configuration) gave 24 and 26,
Stereochemistry of 19 and 21 was confirmed by the
Table 3. gem-Silylborylation of alkylidene-type carbenoids generated by deprotonation
Substrate
Carbenoid
Product
Yield (%)a
75 (E only)
89 (Z only)
a
Isolated yields based on 3 are given.
A solution of 10f (0.50 mmol) in THF (2 mL) was treated with LiTMP (1.05 mmol) and 3 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
b
temperature.
A solution of 10g (0.50 mmol) in THF (2 mL) was treated with BuLi (0.53 mmol) and 3 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
c
temperature.
A solution of 10h (0.50 mmol) in THF (2 mL) was treated with LiTMP (0.53 mmol) and 3 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
temperature.
d

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
6385
Scheme 5. Stereochemical assignment of 19 and 21.
whose configurations were assigned as trans by the vic-
coupling constants of vinyl hydrogens in phenyl-substituted
double bonds being 16.0 and 15.6 Hz, respectively. Thus,
olefinic configuration in 19 and 21 was both assigned as Z.
carbenoids with diborons. Using 11b as a typical carbenoid,
commercially available diborons 6–9 were screened (Fig.
1). The results are shown in Table 4. Bis(pinacolato)diboron
(6)19 and optically active bis((þ)-pinanediolato)diboron (7)
reacted with 11b to give gem-diborylated compounds 29
and 30 in high yields (entries 1 and 2). In contrast, reaction
with bis(neopentanediolato)diboron (8) resulted in low yield
of 31 due probably to its low solubility under the reaction
conditions (entry 3), while any desired diborylated com-
pound was not obtained when bis(catecolato)diboron (9)
was employed (entry 4).
Considering that the 1,2-migration of a carbonaceous
substituent in an ate complex proceeds with inversion of
configuration,6 these stereochemical outcome clearly
demonstrates that, at first, a borate complex 27 forms
from carbenoid 11 and silylborane, and then silyl migration
takes place, giving rise to 28 with inversion of configuration
(Scheme 6). Monitoring the reaction by TLC (after
quenching), the 1,2-migration of a silyl group is apparently
taking place above 2508C.
By use of 6, various kinds of alkylidene-type carbenoids 11
were gem-diborylated as shown in Table 5. Unsubstituted
and 2,2-disubstituted carbenoids 11a and 11c gave
1,1-diborylalkenes 32 and 33 in high yields. Dichloroalkene
10d could also be applied, which after chlorine–lithium
exchange underwent gem-diborylation, giving rise to 34 in
40% yield, while optically active 1,1-diborylalkene 35 was
obtained from the corresponding dibromide 10e in 65%
yield. Double deprotonation of 10f generated 11f which
reacted with 6 to afford 1,1-diborylbutadiene 36 in 89%
yield. gem-Diborylation of lithium carbenoids 11g and 11h
prepared from conjugated chloroalkenes 37 and 38
proceeded smoothly, producing conjugated compounds 37
and 38 bearing two boryl groups at the terminal positions.
2.2. gem-Diborylation of alkylidene-type carbenoids
We next studied gem-diborylation of alkylidene-type
Scheme 6. Plausible mechanism of gem-silylborylation of alkylidene-type
carbenoids with silylborane.
Table 4. Reaction of 11b with diboron 6–9
Entry
B–B
Product
Yield (%)a
1
2
3
4
6
7
8
9
29
30
31
–
93
.99
15
,1
A mixture of 10b (0.53 mmol), THF (2 mL), and Et2O (1 mL) was treated with BuLi (0.50 mmol) and diboron (0.50 mmol) at 21108C for 10 min, then
gradually warmed to room temperature.
a
Isolated yields based on diboron are given.

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T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
Table 5. gem-Diborylation of alkylidene-type carbenoid
Substrate
Carbenoid
Product
Yield (%)a
91
96
40
65
89
82
48
a
Isolated yields based on 6 are given.
A mixture of 10a (0.50 mmol), THF (2 mL), and Et2O (1 mL) was treated with LiTMP (0.50 mmol) and 6 (0.50 mmol) at 21108C for 10 min, then gradually
b
warmed to room temperature.
A mixture of 1,1-dihaloalkene 10c–10e (0.50 mmol), THF (2 mL), and Et2O (1 mL) was treated with BuLi (0.50 mmol) and 6 (0.50 mmol) at 21108C for
c
10 min, then gradually warmed to room temperature.
Et2O (2 mL) was only used as a solvent.
d
e
A solution of 10f (0.50 mmol) in THF (2 mL) was treated with LiTMP (1.05 mmol) and 6 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
temperature.
A solution of 10g (0.50 mmol) in THF (2 mL) was treated with BuLi (0.53 mmol) and 6 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
temperature.
A solution of 10h (0.50 mmol) in THF (2 mL) was treated with LiTMP (0.53 mmol) and 6 (0.50 mmol) at 2908C for 15 min, then gradually warmed to room
temperature.
f
g
2.3. Synthetic applications of gem-dimetallic compounds
silane 25 in 88% yield. Under the same conditions, such an
organic halide as (E)-1-iodo-1-hexene, bromophenylacetyl-
ene, or allyl bromide coupled with 21 to produce the
corresponding alkenylsilanes 39–41 in good yields. In
addition, the cross-coupling of 2,2-disubstituted alkenyl-
boronate 14b and 16b with iodobenzene or 1-iodo-4-
trifluoromethylbenzene also underwent smoothly giving rise
to the corresponding 1-aryl-1-alkenylsilane 42 or 43 in good
yields, respectively. Moreover, the methyldiphenylsilyl
group in alkenylboronate 44, prepared from 10f with 2 in
Since gem-silylborylation and -diborylation were estab-
lished as a novel way to gem-diorganometallics, we further
studied the carbon–carbon bond extension of the gem-
dimetalated compounds in order to demonstrate the
synthetic utility of such bifunctional molecules. Some
examples of Suzuki–Miyaura coupling reaction of 21 are
firstly illustrated in Scheme 7.20 (Dimethylphenylsilyl)boryl-
ated diene 21 reacted with iodobenzene to give alkenyl-

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
6387
Scheme 7. Boron-mediated cross-coupling reaction of gem-silylborylated compounds.
80% yield, did not affect the Pd-catalyzed coupling reaction
with 1-iodo-4-trifluoromethylbenzene as demonstrated at
the bottom of Scheme 7. In all cases, any kinds of silyl
groups including a trimethylsilyl group were not lost inspite
of the basic conditions.
Further elaboration of the coupled products demonstrates
the utility of the silicon functionality. Although the cross-
coupling reaction of 45 with ethyl p-iodobenzoate21,22 or
fluoride-mediated reaction of 42 or 45 with benzaldehyde23
resulted in protodesilylation, alkenyltrimethylsilane 43 was
Scheme 8. Silicon-mediated coupling reaction.

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T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
Scheme 9. Synthetic applications of gem-diborylated compound.
shown to react smoothly with benzaldehyde in THF at 608C
in the presence of anhydrous Bu4NF,24 giving rise to 46 in
74% yield (Scheme 8).
1-silyl-alkenes or 1,1-diboryl-1-alkenes respectively. The
resulting gem-organodimetallic compounds are demon-
strated to be applicable to ready extension of the olefinic
carbon framework and thus are shown to be extremely
versatile reagents in organic synthesis.
Finally shown is the synthetic application of diborylated
compound 29 (Scheme 9). Rh-catalyzed Michael-type
addition reaction of 29 to methyl vinyl ketone proceeded
smoothly to give diketone 47 in 74% yield.25 Two C–B
bonds in 29 were simultaneously converted into two C–C
bonds as exemplified by Pd-catalyzed cross-coupling
reaction, with iodobenzene giving rise to 48. When an
equimolar amount of allyl bromide was used as the coupling
partner, stepwise coupling was found possible. Thus, 29 was
treated with allyl bromide in an equimolar amount to give
allylated alkenylboronate 49. Furthermore, the allylation
followed by coupling with iodobenzene in one pot gave the
corresponding bis-coupled product 50 in a good overall
yield.
4. Experimental
4.1. General remarks
All manipulations of oxygen- and moisture-sensitive
materials were conducted with a standard Schlenk technique
under a purified argon atmosphere (deoxygenated by
passing through BASF-Catalyst R3-11 column at 808C).
1H NMR spectra were measured on a Varian Mercury 200
1
(1H, 200 MHz) spectrometer. Chemical shifts of H NMR
are expressed in parts per million downfield relative to an
internal tetramethylsilane (d¼0 ppm) or chloroform
(d¼7.26 ppm). Splitting patterns are indicated as s,
singlet; d, doublet; t, triplet; q, quartet; m, multiplet; brs,
broad singlet. 13C NMR spectra were measured on a
Varian Mercury 200 (13C, 50 MHz) spectrometer and
JEOL JMN ECP-500 (13C, 125 MHz) spectrometer with
tetramethylsilane as an internal standard (d¼0 ppm). 19F
NMR spectra were measured on a Varian Mercury 200
(19F, 188 MHz) spectrometer with CFCl3 as an internal
3. Conclusion
In conclusion, we have demonstrated that gem-dimetalation
of carbenoids with interelement compounds provides a
novel and highly efficient route to gem-dimetallic com-
pounds. Thus, alkylidene-type lithium carbenoids react with
silylboranes or diborons to stereoselectively afford 1-boryl-

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
6389
standard (d¼0 ppm). Infrared spectra (IR) were recorded
on a Shimadzu FTIR-8400 spectrometer. GC-MS analyses
were obtained with a JEOL JMS-700 spectrometer by
electron ionization at 70 eV. Elemental analyses were
carried out with a YANAKO MT2 CHN CORDER
machine at Kyoto University Elemental Analysis Center.
Melting points were determined using a YANAKO
MP-500D. TLC analyses were performed by means of
Merck Kieselgel 60 F254 and Rf values were given.
Column chromatography was carried out using Wakogel
C-200. Preparative recycling gel permeation chroma-
tography (GPC) was performed with a JAI LC-908
chromatograph equipped with JAIGEL-1H and -2H
columns (chloroform as an eluent). Cooling a reaction
vessel at 2110, 298, or 2788C was effected using
pentane with liquid nitrogen, methanol with liquid
nitrogen, or methanol with dry ice, respectively.
the resulting deep red solution was stirred for 15 min at 08C.
This was diluted with anhydrous THF (10 mL), and
the resultant was immediately cooled to 2788C. To the
solution was added isopropoxy(pinacolato)borane (0.50 g,
2.2 mmol) dropwise at 2788C. Formation of 5 was
confirmed by GC–MS analyses of the crude product
which was used without further purification. MS m/z 200
(Mþ, 1), 185 (Mþ2Me, 27), 143 (11), 101 (37), 84 (100),
69 (90). HRMS calcd for C8H18BO2Si: Mþ2Me, 185.1169.
Found: m/z 185.1166.
4.4. Typical procedure for gem-silylborylation of
alkylidene-type carbenoids generated by deprotonation
4.4.1. 1-Dimethylphenylsilyl-1-(4,4,5,5-tetramethyl-
1,3,2-dioxaborolan-2-yl)ethene (14a). To a solution of
vinyl bromide 10a (1.0 M, 0.50 mL, 0.50 mmol) in THF
(2 mL) and diethyl ether (1 mL) was added a solution of
LiTMP (0.50 mmol) in THF (1 mL) at 21108C. To the
resulting mixture was added 3 (0.13 mg, 0.50 mmol)
dropwise at 21108C. The reaction mixture was stirred for
10 min and then allowed to gradually warm to room
temperature. After quenching with saturated aq. NH4Cl
(1 mL), the mixture was diluted with diethyl ether (20 mL),
and then washed with water (10 mL). The organic layer was
dried over anhydrous magnesium sulfate, and concentrated
in vacuo. Purification by column chromatography on silica
gel (hexane/ethyl acetate 9:1) afforded 14a as a colorless oil
4.2. Materials
Ethereal solvents like THF, 1,4-dioxane, and diethyl ether
were distilled from benzophenone and sodium under an
argon atmosphere. Butyllithium was purchased from
Sigma-Aldrich Co. Inc., and titrated with N-pivaloyl-o-
toluidine as an indicator. (Triphenylsilyl)(pinacolato)-
borane, (methyldiphenylsilyl)(pinacolato)borane, (dimethyl-
phenylsilyl)(pinacolato)borane were synthesized by the
reported procedure.13 Bis(pinacolato)diboron, bis((þ)-
pinanediolato)diboron, bis(2,2-dimethyl-propane-1,3-dio-
lato)diboron, and bis(catecolato)diboron were purchased
from Sigma-Aldrich Chemical Co. Inc. and used as received.
1
(0.12 g, 81% yield). Rf 0.50 (hexane/ethyl acetate 9:1). H
NMR (CDCl3) d 0.40 (s, 6H), 1.21 (s, 12H), 6.20 (d, J¼
5.5 Hz, 1H), 6.67 (d, J¼5.5 Hz, 1H), 7.29–7.36 (m, 2H),
7.51–7.59 (m, 3H). 13C NMR (CDCl3) d 22.7, 24.8, 83.1,
127.5, 128.7, 134.1, 138.7, 145.1. IR (neat) 3050, 2975,
1580, 1420, 1375, 1320, 1300, 1275, 1240, 1215,
1140 cm21. MS m/z 288 (Mþ, 56), 289 (Mþþ1, 13), 273
(100). Anal. calcd for C16H25BO2Si: C, 66.67; H, 8.74.
Found: C, 66.39; H, 8.49.
4.3. Preparation of silylborane 4 and 5
4.3.1. (Dimethylphenylsilyl)((1)-pinanediolato)borane
(4). To a stirred solution of (þ)-pinandiolatoborane (1.1 g,
6.0 mmol) in hexane (5 mL) was added dimethylphenyl-
silyllithium (ca. 2.5 mol/L in THF, 2 mL, 5.0 mmol)
dropwise at 08C. The resulting solution was allowed to
warm gradually to room temperature. Evaporation of the
volatile materials afforded a yellow oil, which was
redissolved in hexane to remove insoluble materials. After
suction filtration, the filtrate was concentrated in vacuo.
Purification of the residue by column chromatography on
silica gel gave 4 as a pale yellow oil (1.0 g, 64% yield).
[a]2D5¼4.018 (c 0.92, CHCl3). Rf 0.50 (hexane/ethyl acetate
4.5. Typical procedure for gem-silylborylation of
alkylidene-type carbenoids generated by halogen–
lithium exchange
4.5.1. [Dimethylphenylsilyl(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)methylene]cyclohexane (14b). Butyl-
lithium in hexane (1.5 M, 1.5 mL, 2.3 mmol) was added
dropwise to a solution of 1,1-(dibromomethylene)cyclo-
hexane (10b) (0.55 mg, 2.2 mmol) in THF (6 mL) and
diethyl ether (3 mL) at 21108C, and stirred at 21108C for
15 min to prepare 11b. The mixture was then treated with 3
(0.62 g, 2.4 mmol), warmed gradually to room temperature,
and further stirred for 12 h at room temperature. After
quenching with saturated aq. NH4Cl (1 mL), the mixture
was diluted with diethyl ether (20 mL) and then washed
with water (10 mL). The organic layer was dried over
anhydrous magnesium sulfate, and concentrated in vacuo.
Purification by column chromatography on silica gel
(hexane/ethyl acetate 9:1) afforded 14b as a colorless oil
1
10:1). H NMR (CDCl3) d 0.36 (s, 6H), 0.85 (s, 3H), 1.02
(d, J¼11 Hz, 1H), 1.28 (s, 3H), 1.40 (s, 3H), 1.82–1.90
(m, 2H), 2.08 (t, J¼6.5 Hz, 1H), 2.14–2.20 (m, 1H), 2.29–
2.34 (m, 1H), 4.25 (d, J¼8.9 Hz, 1H), 7.26–7.36 (m, 3H),
7.57–7.61 (m, 2H). 13C NMR (CDCl3) d 23.0, 22.7,
26.7, 27.1, 28.9, 35.4, 38.0, 39.7, 51.5, 77.2, 77.7, 86.4,
127.6, 128.5, 132.9, 134.0. IR (neat) 2918, 1441, 1375,
1252, 1210, 1120, 837, 700 cm21. MS m/z 315 (Mþþ1, 3),
314 (Mþ, 7), 313 (Mþ21, 2), 135 (57), 93 (100). HRMS
calcd for C18H27BO2Si: Mþ2Me, 299.1639. Found: m/z
299.1639.
1
(0.65 g, 84% yield). Rf 0.44 (hexane/ethyl acetate 9:1). H
4.3.2. (Trimethylsilyl)(pinacolato)borane (5). A solution
of hexamethyldisilane (0.51 mL, 2.5 mmol) in anhydrous
HMPA (2 mL) was cooled at 08C under an argon
atmosphere. To the solution was added an ethereal solution
of methyllithium (1.1 M, 1.9 mL, 2.0 mmol) dropwise, and
NMR (CDCl3) d 0.34 (s, 6H), 1.21 (s, 12H), 1.36–1.72 (m,
6H), 2.13 (t, J¼5.8 Hz, 2H), 2.31 (t, J¼6.0 Hz, 2H), 7.25–
7.65 (m, 5H). 13C NMR (CDCl3) d 20.05, 25.1, 26.1, 28.1,
28.8, 37.7, 39.3, 83.0, 127.4, 128.4, 133.9, 140.8, 168.0. IR
(neat) 2980, 2920, 2850, 1590, 1365, 1330, 1320, 1280,

6390
T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
1250, 1140, 1105, 850, 830, 820, 730, 700 cm21. MS m/z
358 (Mþþ2, 1.7), 357 (Mþþ1, 6), 356 (Mþ, 21), 355
(Mþ21, 5), 196 (100). Anal. calcd for C21H33BO2Si: C,
70.77; H, 9.33. Found: C, 70.53; H, 9.61.
GPC (flow rate 3.6 mL/min, TR¼48 min). Colorless oil. Rf
1
0.40 (hexane/ethyl acetate 10:1). H NMR (CDCl3) d 0.13
(s, 9H), 1.27 (s, 12H), 6.22 (d, J¼5.4 Hz, 1H), 6.58 (d,
J¼5.4 Hz, 1H). 13C NMR (CDCl3) d 21.4, 24.8, 65.9, 83.0,
143.1. IR (neat) 2957, 2926, 1456, 1248, 964, 818,
700 cm21. MS m/z 211 (Mþ2Me, 58), 129 (41), 83
(100). HRMS calcd for C10H20BO2Si: Mþ2Me, 211.1326.
Found: m/z 211.1331.
4.5.2. 1-Triphenylsilyl-1-(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)ethene (12a). Yield: 60%. Colorless
needles. Mp 97.68C. Rf 0.36 (hexane/ethyl acetate 10:1). 1H
NMR (CDCl3) d 1.12 (s, 12H), 6.27 (d, J¼5.6 Hz, 1H), 6.94
(d, J¼5.6 Hz, 1H), 7.30–7.67 (m, 15H). 13C NMR (CDCl3)
d 24.6, 83.3, 127.8, 129.1, 130.1, 134.7, 136.4, 150.0. IR
(KBr) 2924, 2855, 1458, 1427, 1377, 1323, 1302, 1130,
1109, 700 cm21. MS m/z 413 (Mþþ1, 3), 412 (Mþ, 9), 411
(Mþ21, 2), 329 (11), 259 (70), 181 (22), 84 (100). HRMS
calcd for C26H29BO2Si: Mþ, 412.2030. Found: m/z
412.2033.
4.5.7. [Trimethylsilyl(4,4,5,5-tetramethyl-1,3,2-dioxa-
borolan-2-yl)methylene]cyclohexane (16b). Yield: 67%.
Purified by GPC (flow rate 3.6 mL/min, TR¼46 min).
Colorless oil. Rf 0.44 (hexane/ethyl acetate 10:1). 1H
NMR (CDCl3) d 0.16 (s, 9H), 1.29 (s, 12H), 1.51–1.62
(m, 6H), 2.20–2.36 (m, 4H). 13C NMR (CDCl3) d 1.0, 25.1,
26.2, 28.4, 28.8, 36.6, 37.1, 39.2, 82.9, 166.3. IR (neat)
2928, 1593, 1323, 1285, 1246, 1144, 839 cm21. MS m/z 295
(Mþþ1, 3), 294 (Mþ, 12), 293 (Mþ21, 3), 279 (Mþ2Me,
9), 197 (100), 179 (28), 83 (34). HRMS calcd for
C16H31BO2Si: Mþ, 294.2186. Found: m/z 294.2188.
4.5.3. 1-Methyldiphenylsilyl-1-(4,4,5,5-tetramethyl-
1,3,2-dioxaborolan-2-yl)ethene (13a). Yield: 62%. Color-
less oil. Rf 0.37 (hexane/ethyl acetate 10:1). 1H NMR
(CDCl3) d 0.69 (s, 3H), 1.15 (s, 12H), 6.19 (d, J¼5.4 Hz,
1H), 6.80 (d, J¼5.4 Hz, 1H), 7.30–7.55 (m, 10H). 13C
NMR (CDCl3) d 23.6, 24.6, 83.2, 127.5, 128.9, 133.9,
135.7, 136.6, 147.6. IR (neat) 3069, 2978, 1427, 1327, 1304,
1134, 1113, 851, 793, 735, 698 cm21. MS m/z 351 (Mþþ1,
2), 350 (Mþ, 8), 349 (Mþ21, 2), 335 (6), 253 (24), 197
(50), 84 (100). Anal. calcd for C21H27BO2Si: C, 72.00; H,
7.77. Found: C, 72.13; H, 7.63.
4.5.8. [Dimethylphenylsilyl(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)methylene]cyclopentane (17). Yield:
1
84%. Colorless oil. Rf 0.42 (hexane/ethyl acetate 10:1). H
NMR (CDCl3) d 0.39 (s, 6H), 1.20 (s, 12H), 1.45–1.80 (m,
4H), 2.13 (brs, 2H), 2.46 (brs, 2H), 7.25–7.70 (m, 5H). 13C
NMR (CDCl3) d 20.8, 24.9, 26.0, 26.6, 35.8, 36.7, 82.8,
127.5, 128.4, 134.0, 140.4, 173.8. IR (neat) 2976, 1593,
1427, 1369, 1325, 1303, 1271, 1143, 1109, 997, 852, 831,
700 cm21. MS m/z 344 (Mþþ2, 0.3), 343 (Mþþ1, 1.0),
342 (Mþ, 3.3), 327 (12), 264 (16), 259 (18), 245 (100), 227
(21), 182 (51), 167 (24), 135 (37). HRMS calcd for
C20H31BO2Si: Mþ, 342.2186. Found: m/z 342.2193.
4.5.4. 1-Dimethylphenylsilyl-1-[(3aS,4S,6S,7aR )-hexa-
hydro-3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxa-
borol-2-yl]ethene (15a). Yield: 72%. Colorless oil. [a ]2D5¼
2.658 (c 0.75, CHCl3). Rf 0.41 (hexane/ethyl acetate 10:1).
1H NMR (CDCl3) d 0.41 (s, 6H), 0.83 (s, 3H), 1.02 (d,
J¼11.0 Hz, 1H), 1.27 (s, 3H), 1.36 (s, 3H), 1.78–1.88 (m,
2H), 2.01–2.12 (m, 2H), 2.24–2.41 (m, 1H), 4.28 (dd,
J¼8.9, 1.9 Hz, 1H), 6.22 (d, J¼5.7 Hz, 1H), 6.70 (d,
J¼5.7 Hz, 1H), 7.31–7.33 (m, 3H), 7.53–7.56 (m, 2H). 13C
NMR (CDCl3) d 22.6, 24.1, 26.5, 27.2, 28.7, 35.6, 38.2,
39.6, 51.4, 77.2, 77.8, 85.4, 127.4, 128.6, 134.0, 138.6,
145.2. IR (neat) 2920, 1578, 1427, 1325, 1246, 1111, 1030,
818 cm21. MS m/z 340 (Mþ, 1), 325 (Mþ2Me, 8), 205 (9),
191 (17), 135 (100), 93 (64). HRMS (FAB) calcd for
C20H30BO2Si: MHþ 341.2108. Found: m/z 341.2109.
4.5.9. 1-Dimethylphenylsilyl-1-(4,4,5,5-tetramethyl-
1,3,2-dioxaborolan-2-yl)-2,2-diphenylethene (18). Yield:
60%. Purified by GPC (flow rate 3.6 mL/min, TR¼
44.5 min). Colorless needles. Mp 2028C. Rf 0.31 (hexane/
ethyl acetate 10:1). 1H NMR (CDCl3) d 0.08 (s, 6H), 0.99 (s,
12H), 7.00–7.58 (m, 15H). 13C NMR (CDCl3) d 20.6,
24.9, 83.3, 127.1, 127.2, 127.5, 127.6, 127.7, 128.4, 128.5,
128.8, 134.0, 140.9, 144.8, 146.1, 165.4. IR (Nujol) 1561,
1318, 1141, 1105, 840, 734, 700 cm21. MS m/z 442
(Mþþ2, 2.8), 441 (Mþþ1, 9.6), 440 (Mþ, 28.6), 358
(12), 357 (43), 356 (100), 355 (25). Anal. calcd for
C28H33BO2Si: C, 76.35; H, 7.55. Found: C, 76.10; H, 7.67.
4.5.5. {Dimethylphenylsilyl[(3aS,4S,6S,7aR)-hexahydro-
3a,5,5-trimethyl-4,6-methano-1,3,2-benzodioxaborol-2-
yl]methylene}cyclohexane (15b). Yield: 78%. Pale yellow
oil. [a]2D6¼3.848 (c 0.91, CHCl3). Rf 0.46 (hexane/ethyl
acetate 10:1). 1H NMR (CDCl3) d 0.41 (s, 6H), 0.85 (s, 3H),
1.30 (s, 6H), 1.38–1.60 (m, 6H), 1.60–1.74 (m, 4H), 1.82–
1.97 (m, 2H), 2.04–2.24 (m, 2H), 2.30–2.43 (m, 1H), 4.27
(d, J¼8.6 Hz, 1H), 7.30–7.36 (m, 3H), 7.57–7.62 (m, 2H).
13C NMR (CDCl3) d 24.1, 26.1, 26.6, 27.1, 28.1, 28.7, 28.9,
35.5, 37.8, 38.2, 39.5, 39.7, 51.2, 77.4, 77.6, 85.5, 127.5,
128.3, 133.9, 140.8, 168.5. IR (neat) 2926, 2855, 1589,
4.5.10. (1Z,3S )-3-(2-Methoxyethoxy)methoxy-1-
dimethylphenylsilyl-1-(4,4,5,5-tetramethyl-1,3,2-dioxa-
borolan-2-yl)-1-butene (19). Yield: 45%. Colorless oil.
[a ]2D5¼212.38 (c 0.62, CHCl3). Rf 0.32 (hexane/ethyl
acetate 3:1). 1H NMR (CDCl3) d 0.45 (s, 6H), 1.00 (d, J¼
6.2 Hz, 3H), 1.19 (s, 12H), 3.37 (s, 3H), 3.43–3.60 (brs,
4H), 4.26 (dq, J¼6.2, 8.6 Hz, 1H), 4.53 (s, 2H), 6.78
(d, J¼6.8 Hz, 1H), 7.26–7.62 (m, 5H). 13C NMR (CDCl3)
d 20.69, 0.23, 20.5, 24.6, 24.7, 58.9, 66.5, 71.7, 72.8,
83.1, 93.0, 127.6, 128.7, 133.9, 140.2, 161.3. IR (neat)
3060, 3050, 2970, 2950, 2900, 2800, 1600, 1440, 1420,
1370, 1320, 1300, 1270, 1250, 1220, 1140, 1110, 1020,
980, 940, 860, 840, 820 cm21. MS m/z 421 (Mþþ1,0.3),
420 (Mþ, 0.5), 419 (Mþ21, 0.2), 135 (100). Anal. calcd
for C22H37BO5Si: C, 62.85; H, 8.87. Found: C, 62.67; H,
8.93.
1448, 1364, 1325, 1309, 1248, 1211, 1111, 1032, 816 cm21
.
MS m/z 409 (Mþþ1, 2), 408 (Mþ, 7), 407 (Mþ, 2), 393 (4),
330 (5), 196 (21), 135 (100). HRMS calcd for C25H37BO2Si:
Mþ, 408.2656. Found: m/z 408.2639.
4.5.6. 1-Trimethylsilyl-1-(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)ethene (16a). Yield: 45%. Purified by

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
6391
4.5.11. (1E )-1-Dimethylphenylsilyl-1-(4,4,5,5-tetra-
methyl-1,3,2-dioxaborolan-2-yl)-1,3-butadiene (20).
136.5. IR (neat) 3050, 3000, 2950, 2900, 2850, 1610, 1550,
1460, 1420, 1410, 1360, 1320, 1300, 1280, 1260, 1140,
1100, 1000, 980, 950, 920, 910, 860, 840, 820 cm21. MS
m/z 236 (Mþ, 0.06), 129 (100). Anal. calcd for C14H20O3: C,
71.16; H, 8.53. Found: C, 71.36; H, 8.75.
Yield: 75%. Colorless oil. Rf 0.45 (hexane/ethyl acetate
9:1). 1H NMR (CDCl3) d 0.41 (s, 6H), 1.20 (s, 12H), 5.20–
5.40 (m, 2H), 7.30–7.62 (m, 5H). 13C NMR (CDCl3) d
22.0, 24.2, 83.0, 121.7, 128.5, 129.0, 134.0, 138.1, 138.2,
156.0. IR (neat) 3050, 3000, 2950, 2900, 2850, 1610, 1550,
1460, 1420, 1410, 1360, 1320, 1300, 1280, 1260, 1140,
1100, 1000, 980, 950, 920, 910, 860, 840, 820 cm21. MS
m/z 314 (Mþ, 8.3), 171 (100). Anal. calcd for C18H27BO2Si:
C, 68.29; H, 8.66. Found: C, 68.13; H, 8.49.
4.5.15. (1Z, 3E )-1-Dimethylphenylsilyl-1-phenyl-1,3-
decadiene (25). Yield: 94%. Colorless oil. Rf 0.41 (hexane).
1H NMR (CDCl3) d 0.39 (s, 6H), 0.89 (t, J¼6.8 Hz, 3H),
1.24 (broad, 8H), 2.00 (m, 2H), 5.77 (dt, J¼14.4, 6.8 Hz,
1H), 6.24 (dd, J¼14.4, 11.4 Hz, 1H), 6.76 (d, J¼11.4 Hz,
1H), 7.07–7.65 (m, 10H). 13C NMR (CDCl3) d 20.14,
14.1, 22.6, 28.7, 31.7, 32.6, 125.5, 127.5, 127.8, 127.9,
128.9, 129.6, 133.9, 138.8, 139.4, 140.5, 145.7, 146.7. IR
(neat) 3060, 3050, 2950, 2920, 2850, 1640, 1600, 1480,
1420, 1250, 1100, 970, 830, 810, 780, 730, 700 cm21. MS
m/z 350 (Mþþ2, 1), 349 (Mþþ1, 5), 348 (Mþ, 16), 135
(100). Anal. calcd for C24H32Si: C, 82.69; H, 9.25. Found:
C, 82.93; H, 9.51.
4.5.12. (1Z,3E )-1-Dimethylphenylsilyl-1-(4,4,5,5-tetra-
methyl-1,3,2-dioxaboro-lan-2-yl)-1,3-decadiene (21).
Yield: 89%. Colorless oil. Rf 0.50 (hexane/ethyl acetate
1
9:1). H NMR (CDCl3) d 0.45 (s, 6H), 0.87 (t, J¼6.6 Hz,
3H), 1.20–1.36 (brs, 20H), 1.98 (m, 2H), 5.86 (dt, J¼14.8,
6.8 Hz, 1H), 6.15 (dd, J¼14.8, 11.0 Hz, 1H), 7.25–7.35 (m,
3H), 7.49 (d, J¼11.0 Hz, 1H), 7.54–7.60 (m, 2H). 13C
NMR (CDCl3) d 20.1, 14.1, 22.6, 24.7, 28.5, 31.6, 32.6,
82.8, 127.5, 128.4, 131.6, 133.9, 140.8, 142.1, 158.3. IR
(neat) 2930, 1631, 1546, 1325, 1143 cm21. MS m/z 399
(Mþþ1, 3), 398 (Mþ, 6), 397 (Mþ21, 3), 135 (100).
HRMS calcd for C24H39BO2Si: Mþ, 398.2810. Found: m/z
398.2812.
4.5.16. (1E,3E )-1-Phenyl-1,3-decadiene (26). Yield: 84%.
1
Colorless oil. Rf 0.80 (hexane/ethyl acetate 9:1). H NMR
(CDCl3) d 0.92 (t, J¼6.5 Hz, 3H), 1.21–1.62 (broad, 8H),
2.16 (m, 2H), 5.85 (dt, J¼7.1, 15.1 Hz, 1H), 6.23 (dd,
J¼15.6, 10.2 Hz, 1H), 6.46 (d, J¼15.6 Hz, 1H), 6.78 (dd,
J¼15.6, 10.2 Hz, 1H). The registry number for (26):
[62060-09-7].26
4.5.13. (E ) and (Z )-1-Dimethylphenylsilyl-1-(4,4,5,5-
tetramethyl-1,3,2-dioxaborolan-2-yl)-1-decen-3-yne
(22). Yield: 49% (E/Z¼1:1). Colorless oil. Rf 0.50
4.6. Typical procedure for gem-diborylation of
alkylidene-type carbenoids
1
(hexane/ethyl acetate 9:1). H NMR (CDCl3) d 0.41 (s,
6H), 0.92 (t, 3H), 1.21 (s, 12H), 1.20–1.31 (brs, 8H), 2.29
(dt, J¼6.5, 2.1 Hz, 2H), 6.21 (s, 1H), 7.30–7.61 (m, 5H).
13C NMR (CDCl3) d 22.6, 14.0, 19.6, 22.5, 24.6, 28.5,
31.3, 83.1, 94.6, 127.2, 128.3, 133.9, 137.5. IR (neat) 2970,
2940, 2840, 2050, 1550, 1460, 1420, 1380, 1320, 1300,
1250, 1210, 1150, 1100, 1010, 980, 950 cm21. MS m/z 398
(Mþþ2, 1), 397 (Mþþ1, 2), 396 (Mþ, 8), 395 (Mþ21, 2),
253 (100). HRMS calcd for C24H37BO2Si: Mþ, 396.2654.
Found: m/z 396.2656.
4.6.1. [Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)methylene]cyclohexane (29). Butyllithium in hexane
(1.50 M, 0.15 mL, 0.22 mmol) was added dropwise to a
solution of 1,1-(dibromomethylene)cyclohexane (1b)
(51 mg, 0.20 mmol) in THF (1 mL) and diethyl ether
(0.5 mL) at 21108C, and the resulting solution was stirred
at 21108C for 10 min. To the resulting solution of
(bromolithiomethylene)cyclohexane was added dropwise a
solution of bis(pinacolato)diboron (6) (56 mg, 0.22 mmol)
in THF (1 mL). The mixture was gradually warmed to room
temperature and stirred for 12 h. The reaction mixture was
quenched with saturated aq. NH4Cl (1 mL), diluted with
diethyl ether (10 mL), and treated with water (3 mL). The
organic layer was separated, dried over anhydrous mag-
nesium sulfate, and concentrated to give a colorless solid,
which was purified by column chromatography on silica gel
(hexane/ethyl acetate 9:1) to give 29 as colorless plates
(65 mg, 93% yield). Mp 778C. Rf 0.31 (hexane/ethyl acetate
9:1). 1H NMR (CDCl3) d 1.25 (s, 24H), 1.50–1.70 (m, 6H),
2.30–2.45 (m, 4H). 13C NMR (CDCl3) d 24.7, 26.4, 28.7,
37.4, 82.7, 171.5. IR (Nujol) 1615, 1320, 1285, 1265, 1245,
1220, 1140, 1105, 1010, 985, 965, 890, 855, 670 cm21. MS
m/z 350 (Mþþ2, 0.2), 349 (Mþþ1, 2), 348 (Mþ, 8), 347
(Mþ21, 4), 333 (Mþ2Me, 8), 291 (100). Anal. calcd for
C19H34B2O4: C, 65.56; H, 9.84%. Found: C, 65.31; H,
10.03%.
4.5.14. Cross-coupling/protodesilylation of 19. A mixture
of 19 (42 mg, 0.10 mmol), iodobenzene (30 mg, 0.15
mmol), Pd(PPh3)4 (3.5 mg, 3.0 mmol), and 3 M KOH
aqueous solution (0.20 mL, 0.60 mmol) in dioxane (1 mL)
was heated at 908C for 12 h. The reaction mixture was
diluted with diethyl ether (10 mL), washed with water
(3 mL). The organic layer was then separated, dried over
anhydrous MgSO4, and concentrated to give crude 23. To a
solution of crude 23 in THF (2 mL) was added 1 M solution
of tetrabutylammonium fluoride in THF (1 mL), and the
resulting solution was heated at 508C for 3 h. The mixture
was diluted with diethyl ether (3 mL) and treated with water
(3 mL). The organic layer was separated, dried over
anhydrous MgSO4, and concentrated. The crude product
was purified by column chromatography on silica gel to give
(E,3S )-3-(2-methoxyethoxy)methoxy-1-phenyl-1-butene
(24) as a colorless oil (17 mg, 72% yield). [a]2D4¼26.188
(c 1.06, CHCl3). Rf 0.32 (hexane/ethyl acetate 9:1). 1H
NMR (CDCl3) d 1.35 (d, J¼6.4 Hz, 1H), 3.38 (s, 3H),
3.52–3.87 (m, 4H), 4.40 (m, 1H), 4.78 (dd, J¼7.0, 23.1 Hz,
1H), 6.10 (dd, J¼7.4, 16.0 Hz, 1H), 6.56 (d, J¼16.0 Hz,
1H), 7.22–7.41 (m, 5H). 13C NMR (CDCl3) d 21.5, 59.0,
66.8, 71.8, 72.6, 92.7, 126.4, 127.6, 128.5, 130.7, 131.5,
4.6.2. {Bis[(3aS,4S,6S,7aR )-hexahydro-3a,5,5-trimethyl-
4,6-methano-1,3,2-benzodioxaborol-2-yl]methylene}-
cyclohexane (30). Yield: 99%. Colorless oil. [a ]2D5¼8.218
1
(c 0.73, CHCl3). Rf 0.51 (hexane/ethyl acetate 10:1). H
NMR (CDCl3) d 0.84 (s, 6H), 1.28 (s, 6H), 1.38 (s, 6H),

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T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
1.50–1.69 (m, 6H), 1.81–1.95 (m, 4H), 2.02–2.20 (m, 4H),
2.21–2.38 (m, 2H), 2.38–2.46 (m, 2H), 4.29 (dd, J¼2.2,
6.6 Hz, 2H). 13C NMR (CDCl3) d 24.0, 26.4, 27.1, 28.7,
35.7, 37.6, 37.7, 38.1, 39.5, 51.4, 76.4, 77.4, 85.1, 171.5. IR
(neat) 2926, 2868, 1618, 1448, 1375, 1327, 1310, 1273,
1215, 1123, 1078, 1034, 995, 756, 735 cm21. MS m/z 453
(Mþþ1, 4), 452 (Mþ, 11), 451 (Mþ21, 5), 342 (3), 135
(100), 93 (56). HRMS calcd for C27H42B2O4: Mþ,
452.3269. Found: m/z 452.3284.
4.6.8. 1,1-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)-1,3-butadiene (36). Yield: 89%. Colorless oil. Rf 0.25
(hexane/ethyl acetate 9:1). H NMR (CDCl3) d 1.24 (s,
1
12H), 1.29 (s, 12H), 5.35 (d, J¼10.9 Hz, 2H), 5.42 (d, J¼
17.5 Hz, 1H), 6.79 (ddd, J¼17.5, 10.9, 10.4 Hz, 1H), 7.30
(d, J¼10.4 Hz, 1H). 13C NMR (CDCl3) d 24.7, 83.0, 83.2,
123.1, 138.0, 157.8. IR (Nujol) 1620, 1560, 1320, 1260,
1210, 1140, 1110, 1010, 990, 965, 910, 855 cm21. MS m/z
308 (Mþþ2, 2), 307 (Mþþ1, 11), 306 (Mþ, 69), 305
(Mþ21, 31), 304 (Mþ22, 4), 291 (Mþ2Me, 26), 206
(100). HRMS calcd for C16H28B2O4: Mþ, 306.2172. Found:
m/z 306.2173.
4.6.3. Bis(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)methyl-
ene]cyclohexane (31). Yield: 15%. Colorless needles. Mp
52.48C. Rf 0.10 (hexane/ethyl acetate 10:1). 1H NMR
(CDCl3) d 0.98 (s, 12H), 1.53–1.60 (m, 6H), 2.33 (m, 4H),
3.63 (s, 8H). 13C NMR (CDCl3) d 21.9, 26.5, 28.9, 31.6,
37.2, 72.1, 165.5. IR (KBr) 2924, 2855, 1618, 1464, 1404,
1294, 1224, 1107 cm21. MS m/z 321 (Mþþ1, 13), 320
(Mþ, 65), 319 (Mþ21, 32), 234 (66), 135 (42), 69 (100).
HRMS calcd for C17H30B2O4: Mþ, 320.2330. Found: m/z
320.2356.
4.6.9. (3E )-1,1-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaboro-
lan-2-yl)-1,3-decadiene (37). Yield: 82%. Colorless oil.
1
Rf 0.29 (hexane/ethyl acetate 10:1). H NMR (CDCl3) d
0.87 (t, J¼6.6 Hz, 3H), 1.23 (s, 12H), 1.30 (s, 12H), 1.20–
1.38 (brs, 8H), 2.11 (m, 2H), 5.96 (dd, J¼15.1, 6.8 Hz, 1H),
6.49 (dd, J¼15.1, 11.0 Hz, 1H), 7.32 (d, J¼11.0 Hz, 1H).
13C NMR (CDCl3) d 14.1, 22.6, 24.8, 28.7, 28.8, 31.7, 32.8,
82.8, 83.1, 131.8, 142.3, 158.6. IR (neat) 2980, 2930, 2855,
1740, 1630, 1570, 1460, 1400, 1365, 1350, 1290, 1265, 1210,
1140, 1105, 1010, 985, 910, 850, 730, 660 cm21. MS m/z 392
(Mþþ2, 1), 391 (Mþþ1, 9), 390 (Mþ, 36), 389 (Mþ21, 18),
375 (Mþ2Me, 10), 131 (100). Anal. calcd for C22H40B2O4:
C, 67.72; H, 10.33%. Found: C, 67.80; H, 10.53%.
4.6.4. 1,1-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)ethene (32). Yield: 91%. Colorless plates. Mp 81.28C.
Rf 0.25 (hexane/ethyl acetate 9:1). 1H NMR (CDCl3) d 1.26
(s, 24H), 6.58 (s, 2H). 13C NMR (CDCl3) d 24.7, 83.1,
147.9. IR (Nujol) 1590, 1385, 1305, 1280, 1200, 1150,
1110, 1100, 980, 855 cm21. MS m/z 280 (Mþ, 56), 265
(Mþ2Me, 79), 84 (100). Anal. calcd for C14H26B2O4: C,
60.06; H, 9.36%. Found: C, 60.09; H, 9.31%.
4.6.10. 1,1-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)-1-decen-3-yne (38). Yield: 48%. Colorless oil. Rf 0.36
(hexane/ethyl acetate 10:1). 1H NMR (CDCl3) d 0.88
(t, J¼6.5 Hz, 3H), 1.22 (s, 12H), 1.31 (s, 12H), 2.32 (dt, J¼
2.2, 6.9 Hz, 2H), 6.71 (s, 1H). 13C NMR (CDCl3) d 14.0,
19.7, 22.5, 24.6, 24.7, 28.5, 31.3, 83.2, 83.4, 97.2, 136.0. IR
(neat) 2980, 2930, 2860, 2200, 1560, 1460, 1400, 1340,
4.6.5. [Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-
methylene]cyclopentane (33). Yield: 96%. Colorless
1
plates. Mp 73.58C. Rf 0.45 (hexane/ethyl acetate 4:1). H
NMR (CDCl3) d 1.24 (s, 24H), 1.59–1.67 (m, 4H), 2.44–
2.52 (m, 4H). 13C NMR (CDCl3) d 24.8, 26.2, 36.0, 82.5,
178.8. IR (Nujol) 1620, 1320, 1140, 1010, 990, 855,
720 cm21. MS m/z 335 (Mþþ1, 1), 334 (Mþ, 6), 333
(Mþ21, 2), 319 (Mþ2Me, 9), 277 (100). Anal. calcd for
C18H32B4O4: C, 64.72; H, 9.65. Found: C, 64.46; H, 9.88.
1250, 1210, 1140, 1105, 1010, 990, 960, 850, 830 cm21
.
MS m/z 389 (Mþþ1, 2), 388 (Mþ, 7), 387 (Mþ21, 7), 373
(Mþ2Me, 26), 84 (100). Anal. calcd for C22H38B2O4: C,
68.07; H, 9.87%. Found: C, 68.15; H, 10.07%.
4.7. Cross-coupling of gem-silylborylated compounds
4.6.6. 1,1-Bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)-2,2-diphenylethene (34). Yield: 40%. Colorless
needles. Mp 182.88C. Rf 0.41 (hexane/ethyl acetate 4:1).
1H NMR (CDCl3) d 1.14 (s, 12H), 7.24 (s, 10H). 13C NMR
(CDCl3) d 24.4, 83.0, 127.4, 127.6, 129.3, 144.4, 164.5. IR
(Nujol) 2977, 1560, 1442, 1371, 1290, 1269, 1141, 1014,
848, 700 cm21. MS m/z 433 (Mþþ1, 5), 432 (Mþ, 11), 431
(Mþ21, 4), 274 (100), 83 (24). Anal. calcd for
C26H34B2O4: C, 7.93; H, 72.26. Found: C, 7.99; H, 72.18.
4.7.1. (5E,7Z,9E )-7-Dimethylphenylsilyl-hexadeca-5,7,9-
triene (39). A mixture of 21 (0.10 mmol), (E )-1-iodo-1-
hexene (32 mg, 0.15 mmol), Pd(PPh3)4 (3.5 mg, 3.0 mmol),
and 3 M KOH aqueous solution (0.20 mL, 0.60 mmol) in
dioxane (1 mL) was heated at 908C for 12 h. The reaction
mixture was diluted with diethyl ether (10 mL) and washed
with water (3 mL). The organic layer was then separated,
dried over anhydrous MgSO4, and concentrated. The
resulting crude product was purified by column chroma-
tography (silica gel) to give 39 as a colorless oil (27 mg,
4.6.7. (S )-3-(2-Methoxyethoxy)methoxy-1,1-bis(4,4,5,5-
tetramethyl-1,3,2-dioxaborolan-2-yl)-1-butene (35). Yield:
65%. Colorless oil. [a]D25¼248.48 (c 1.06, MeOH). Rf 0.42
1
76% yield). Rf 0.72 (hexane). H NMR (CDCl3) d 0.39 (s,
6H), 0.83–0.95 (m, 6H), 1.14–1.46 (m, 12H), 1.94–2.21
(m, 4H), 5.52 (dt, J¼12.0, 7.4 Hz, 1H), 5.78 (dt, J¼14.8,
7.4 Hz, 1H), 6.37 (d, J¼10.8 Hz, 1H), 6.52 (d, J¼14.8 Hz,
1H), 6.62 (ddt, J¼14.8, 10.8, 1.4 Hz, 1H), 7.28–7.40 (m,
3H), 7.40–7.58 (m, 2H). 13C NMR (CDCl3) d 21.8, 13.9,
14.1, 22.1, 22.6, 28.9, 29.3, 31.6, 31.7, 33.0, 33.3, 124.2,
126.4, 127.6, 128.2, 128.7, 134.0, 134.8, 135.6, 137.7,
139.4. IR (neat) 2957, 2926, 1684, 1558, 1248, 1111,
964 cm21. MS m/z 355 (Mþþ1, 4), 354 (Mþ, 13), 297 (10),
135 (100). HRMS calcd for C24H38Si: Mþ, 354.2743.
Found: m/z 354.2742.
1
(hexane/ethyl acetate 1:1). H NMR (CDCl3) d 1.20–1.29
(m, 3H), 1.23 (s, 12H), 1.28 (s, 12H), 3.38 (s, 3H), 3.50–
3.80 (m, 4H), 4.42 (t, J¼6.0 Hz, 1H), 4.69 (s, 2H), 6.76
(d, J¼5.1 Hz, 1H). 13C NMR (CDCl3) d 20.7, 24.5, 24.7,
24.8, 58.9, 66.6, 71.7, 73.3, 82.9, 83.1, 93.4, 159.6. IR (neat)
2980, 2930, 2890, 2810, 1620, 1465, 1445, 1390, 1370,
1350, 1330, 1300, 1250, 1210, 1140, 1110, 1040, 985, 965,
920, 855, 750, 660 cm21. MS m/z 397 (Mþ2Me, 0.4), 131
(100). Anal. calcd for C20H38B2O7: C, 58.29; H, 9.29%.
Found: C, 58.13; H, 9.02%.

T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
6393
4.7.2. (3Z,5E )-3-Dimethylphenylsilyl-1-phenyl-dodeca-
3,5-dien-1-yne (40). Yield: 99%. Colorless oil. Rf 0.67
(hexane). 1H NMR (CDCl3) d 0.51 (s, 6H), 0.87 (t,
J¼6.8 Hz, 3H), 1.10–1.38 (m, 10H), 1.98 (q, J¼6.2 Hz,
2H), 5.81 (dt, J¼14.8, 6.8 Hz, 1H), 6.15 (ddt, J¼12.2, 7.2,
1.2 Hz, 1H), 7.20 (d, J¼12.2 Hz, 1H). 13C NMR (CDCl3) d
21.2, 14.1, 22.6, 28.5, 28.7, 31.6, 32.7, 93.5, 94.2, 120.1,
124.4, 127.5, 127.9, 128.2, 129.1, 129.5, 131.2, 133.9,
138.2, 140.7, 151.5. IR (neat) 3051, 2957, 2926, 2855, 1626,
1488, 1250, 106, 968, 818, 754, 700, 691 cm21. MS m/z 373
(Mþþ1, 12), 372 (Mþ, 34), 371 (Mþ21, 7), 287 (66), 135
(100). HRMS calcd for C26H32Si: Mþ, 372.2273. Found:
m/z 372.2260.
136.8, 138.3, 157.3. IR (neat) 3068, 2977, 2929, 1552, 1427,
1362, 1302, 1259, 1143, 1109, 999, 975, 856, 808,
700 cm21. MS m/z 376 (Mþ, 9), 197 (50), 105 (12), 84
(100). Anal. calcd for C23H29BO2Si: C, 73.40; H, 7.84.
Found: C, 73.40; H, 7.77.
4.7.7. (1Z )-1-(4-Trifluoromethylphenyl)buta-1,3-diene
(45). Yield: 85%. Colorless oil. Rf 0.67 (hexane/ethyl
acetate 10:1). 1H NMR (CDCl3) d 0.6 (s, 3H), 5.2 (m, 2H),
6.30 (m, 1H), 6.60 (d, J¼10.9 Hz, 1H), 7.00 (d, J¼7.9 Hz,
1H), 7.31–7.72 (m, 14H). 13C NMR (CDCl3) d 24.0,
121.1. 124.9 (q, J¼3.8 Hz), 127.9, 128.2 (q, J¼246 Hz),
128.7, 129.6, 133.7, 134.9, 135.2, 141.9, 143.6, 145.6 19F
NMR (CDCl3) d 262.8. IR (neat) 3068, 2960, 1614, 1564,
1429, 1408, 1325, 1167, 1119, 1068, 1018, 930, 795, 727,
740, 702, 669, 609 cm21. MS m/z 314 (Mþþ2, 1), 313
(Mþþ1, 16), 312 (Mþ, 16), 295 (11), 227 (12), 135 (100).
Anal. calcd for C24H21F3Si: C, 73.07; H, 5.37. Found: C,
73.24; H, 5.50.
4.7.3. (4Z,6E)-4-(Dimethylphenylsilyl)-trideca-1,4,6-tri-
ene (41). Yield: 68%. Colorless oil. Rf 0.50 (hexane/ethyl
1
acetate 10:1). H NMR (CDCl3) d 0.43 (s, 6H), 0.88 (t,
J¼6.6 Hz, 3H), 1.22 (brs, 8H), 1.96 (q, J¼6.4 Hz, 2H),
2.92 (d, J¼6.2 Hz, 2H), 5.49 (d, J¼16 Hz, 1H), 5.00 (d,
J¼11.6 Hz, H), 6.63 (d, J¼11.2 Hz, 1H), 7.28–7.42 (m,
3H), 7.48–7.60 (m, 2H). 13C NMR (CDCl3) d 20.9, 14.1,
22.6, 28.7, 28.9, 31.7, 32.5, 42.1, 115.4, 127.8, 128.8, 129.6,
133.9, 136.3, 136.4, 138.1, 139.3, 143.7. IR (neat) 2957,
2926, 2855, 1638, 1572, 1427, 1248, 1111, 966, 910, 833,
916, 773, 729, 700 cm21. MS m/z 314 (Mþþ2, 1), 313
(Mþþ1, 16), 312 (Mþ, 16), 295 (11), 227 (12), 135 (100).
Anal. calcd for C21H32Si: C, 80.70; H, 10.32. Found: C,
80.41; H, 10.59.
4.8. Silicon mediated coupling reaction
4.8.1. 2,2-Cyclohexylidene-1-phenyl-2-(4-trifluoro-
methylphenyl)ethanol (46). A THF solution of anhydrous
Bu4NF (1.0 M, 1.0 mL, 1.0 mmol) was added to 43 (62 mg,
0.20 mmol) and benzaldehyde (42 mg, 0.40 mmol) under an
argon atmosphere. The resulting solution was stirred at 608C
for 24 h. The reaction mixture was diluted with diethyl ether
(10 mL) and washed with saturated aq. NH4Cl (6 mL). The
organic layer was then separated, dried over MgSO4, and
concentrated. The crude product was purified by column
chromatography (silica gel) to give 46 as a colorless plates
(51 mg, 74% yield). Mp 44.18C. Rf 0.29 (hexane/ethyl
acetate 4:1). 1H NMR (CDCl3) d 1.61–1.92 (m, 8H), 2.50–
2.64 (m, 2H), 2.65 (s, 1H), 6.05 (s, 1H), 7.19–7.58 (m, 9H).
13C NMR (CDCl3) d 26.7, 28.2, 28.4, 30.6, 32.9, 36.8, 71.3,
124.3 (q, J¼273 Hz), 124.6 (q, J¼38 Hz), 125.7, 127.0,
128.1, 130.8, 133.1, 140.0, 142.4, 142.7. 19F NMR (CDCl3)
d 262.8. IR (neat) 3375, 2928, 2855, 1614, 1450, 1325,
1168, 1123, 1067, 1020, 843, 704 cm21. MS m/z 347
(Mþþ1, 5), 346 (Mþ, 23), 345 (Mþ21, 1), 328 (100), 285
(52), 107 (57), 79 (35). HRMS calcd for C21H21F3O: Mþ,
346.1544. Found: m/z 354.1545.
4.7.4. [(Dimethylphenylsilyl)phenylmethylene]cyclo-
hexane (42). Yield: 82%. Colorless oil. Rf 0.47 (hexane).
1H NMR (CDCl3) d 0.17 (s, 6H), 1.47 (brs, 6H), 1.97 (m,
2H), 2.18 (m, 2H), 6.91–7.00 (m, 1H), 7.08–7.20 (m, 1H),
7.21–7.29 (m, 2H), 7.29–7.40 (m, 3H), 7.56–7.66 (2H).
13C NMR (CDCl3) d 20.2, 26.5, 28.3, 28.7, 33.3, 35.8,
124.8, 127.7, 127.9, 128.4, 128.5, 132.1, 133.7, 140.5,
145.0, 155.0. IR (neat) 2958, 2894, 1605, 1455, 1402, 1337,
1248, 1111, 937, 830, 707 cm21. MS m/z 308 (Mþþ2, 2),
307 (Mþþ1, 7), 306 (Mþ, 20), 261 (15), 228 (100), 135
(85), 121 (24). Anal. calcd for C21H36Si: C, 82.29; H, 8.55.
Found: C, 82.54; H, 8.66.
4.7.5. [(Trimethylsilyl)(4-trifluoromethyphenyl)metyl-
ene]cyclohexane (43). Yield: 82%. Purified by GPC (flow
rate 3.6 mL/min, TR¼48 min). Colorless plates. Mp 32.48C.
4.9. Boron mediated coupling reaction of gem-diboryl-
ated compounds
1
Rf 0.51 (hexane). H NMR (CDCl3) d 0.03 (s, 9H), 1.40–
1.92 (m, 6H), 1.86 (t, J¼6.0 Hz, 2H), 2.38 (t, J¼6.6 Hz,
2H), 6.97 (d, J¼7.4 Hz, 2H), 7.50 (d, J¼7.4 Hz, 2H). 13C
NMR (CDCl3) d 0.76, 26.5, 28.7, 28.9, 33.4, 35.1, 35.2,
124.5 (q, J¼295 Hz), 124.7, 127.0 (q, J¼31 Hz), 133.8,
149.6, 154.0. 19F NMR (CDCl3) d 262.5. IR (neat) 2953,
2920, 2897, 1605, 1448, 1402, 1323, 1248, 1153, 1124,
1101, 935, 837, 797 cm21. MS m/z 313 (Mþþ1, 17), 312
(Mþ, 70), 311 (Mþ21, 1), 297 (98), 220 (68), 73 (100).
Anal. calcd for C17H23F3Si: C, 65.35; H, 7.42. Found: C,
65.34; H, 7.50.
4.9.1. 5,5-(Cyclohexylidene)nonan-2,8-dione (47). Metha-
nol (1 mL) was added to
a flask charged with
Rh(acac)(CO)2 (1.5 mg, 6.0 mmol), 1,3-bis(diphenyl-
phosphino)propane (2.5 mg, 6.0 mmol), and 29 (35 mg,
0.10 mmol). After being stirred for 15 min at room
temperature, the mixture was treated with water (0.20 mL)
and methyl vinyl ketone (28 mg, 0.40 mmol). The resulting
mixture was stirred at 508C for 24 h, diluted with diethyl
ether (10 mL), and washed with water (3 mL). The organic
layer was then separated, dried over MgSO4, and concen-
trated. The resulting crude product was purified by column
chromatography on silica gel to give 47 as a colorless oil
4.7.6. (1E )-1-Methyldiphenylsilyl-1-(4,4,5,5-tetra-
methyl-1,3,2-dioxaborolan-2-yl)-1,3-butadiene
(44).
1
Yield: 80%. Colorless oil. Rf 0.50 (hexane/ethyl acetate
10:1). 1H NMR (CDCl3) d 0.70 (s, 3H), 1.13 (s, 12H), 5.32
(m, 2H), 6.91 (m, 2H), 7.30–7.60 (brs, 5H). 13C NMR
(CDCl3) d 23.2, 24.7, 83.2, 121.8, 127.5, 129.0, 135.3,
(17 mg, 74% yield). Rf 0.32 (hexane/ethyl acetate 9:1). H
NMR (CDCl3) d 1.51 (s, 8H), 2.05–2.31 (broad, 14H), 2.45
(t, J¼6.2 Hz, 4H). 13C NMR (CDCl3) d 25.9, 26.8, 28.4,
30.0, 30.4, 43.3, 126.0, 135.9, 208.9. IR (neat) 3400, 2900,

6394
T. Kurahashi et al. / Tetrahedron 58 (2002) 6381–6395
1700, 1440, 1380, 1220, 1120, 1040, 940, 900, 840 cm21
.
Technology, Japan. Japan Society for the Promotion of
Science (JSPS) is highly acknowledged for the financial
support to T. K. and T. H. as predoctoral research students.
MS m/z 237 (Mþþ1, 2), 236 (Mþ, 100), 235 (Mþ21, 10).
HRMS (FAB) calcd for C15H24O2: Mþ, 236.1776. Found:
m/z 236.1742.
4.9.2. 1,1-Diphenylmethylenecyclohexane (48). A mixture
of 29 (35 mg, 0.10 mmol), iodobenzene (61 mg, 0.30
mmol), Pd(PPh3)4 (3.5 mg, 3 mmol), and 3 M KOH aqueous
solution (0.20 mL, 0.60 mmol) in dioxane (1 mL) was
heated at 908C for 24 h. Workup followed by column
chromatography on silica gel gave 48 as colorless plates
(20 mg, 80% yield). Mp 73.28C. Rf 0.70 (hexane/ethyl
acetate 9:1). 1H NMR (CDCl3) d 1.60 (m, 6H), 2.24 (m, 4H),
7.10–7.32 (m, 10H). 13C NMR (CDCl3) d 26.8, 28.7, 32.4,
126.0, 127.8, 129.8, 134.5, 139.1, 143.1. IR (Nujol) 3400,
2900, 1700, 1440, 1380, 1220, 1120, 1040, 940, 900,
840 cm21. MS m/z 250 (Mþþ2, 2), 249 (Mþþ1, 21), 248
(Mþ, 100). Anal. calcd for C19H20: C, 91.88; H, 8.12.
Found: C, 91.61; H, 8.28.
References
1. (a) Marek, I.; Normant, J.-F. Chem. Rev. 1996, 96,
3241–3267. (b) Marek, I. Chem. Rev. 2000, 100,
2887–2900. (c) Normant, J. F. Acc. Chem. Res. 2001, 34,
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Synthesis; CRC: Boca Raton, 1994. (e) Matsubara, S.;
Oshima, K.; Utimoto, K. J. Organomet. Chem. 2001, 39,
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New York, 1999; pp 119–137.
4.9.3. 4,4-Cyclohexylidene-4-(4,4,5,5-tetramethyl-1,3,2-
dioxaborolan-2-yl)-1-butene (49).
2. The term interelement is used for chemical bonds such as
mutual linkages within main group elements and linkages
between a main group element and a transition metal. See,
Special Volume entitled ‘The Chemistry of Interelement
Linkage’ J. Organomet. Chem. 2000, 611, 1–614.
A mixture of 29
(35 mg, 0.10 mmol), allyl bromide (12 mg, 0.10 mmol),
Pd(PPh3)4 (3.5 mg, 3.0 mmol), and 3 M KOH aqueous
solution (0.10 mL, 0.30 mmol) in dioxane (1 mL) was
heated at 708C for 12 h. Workup followed by column
chromatography on silica gel to give 49 as a colorless oil
3. (a) Casson, S.; Kocienski, P. Contemp. Org. Synth. 1995, 2,
19–34. (b) Beletskaya, I.; Moberg, C. Chem. Rev. 1999, 99,
3435–3461. (c) Han, L.-B.; Tanaka, M. Chem. Commun.
1999, 395–402. (d) Suginome, M.; Ito, Y. Chem. Rev. 2000,
100, 3221–3256.
1
(22 mg, 83% yield). Rf 0.61 (hexane/ethyl acetate 3:1). H
NMR (CDCl3) d 1.25 (m, 12H), 1.55 (m, 6H), 2.18 (m, 2H),
2.44 (m, 2H), 2.88 (d, J¼6.0 Hz, 2H), 5.87 (m, 1H), 4.91 (d,
J¼2.1 Hz, 1H), 4.93 (dd, J¼14.3, 2.1 Hz, 1H), 5.87 (m,
1H). 13C NMR (CDCl3) d 25.5, 27.6, 28.9, 29.6, 31.6, 35.0,
35.8, 83.5, 114.4, 138.9, 146.2, 156.4. IR (neat) 2976, 2926,
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1624, 1359, 1329, 1225, 1148, 1107, 991, 964, 851 cm21
.
MS m/z 263 (Mþþ1, 8), 262 (Mþ, 42), 261 (Mþ21, 9), 205
(52), 161 (50),101 (100), 84 (92). Anal. calcd for
C16H27BO2: C, 73.29; H, 10.38. Found: C, 73.02; H, 10.29.
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4.9.4. 3,3-Cyclohexylidene-3-phenyl-1-butene (50). A
mixture of 29 (35 mg, 0.10 mmol), allyl bromide (12 mg,
0.10 mmol), Pd(PPh3)4 (3.5 mg, 3.0 mmol), and 3 M KOH
aqueous solution (0.20 mL, 0.60 mmol) in dioxane (1 mL)
was heated at 708C for 12 h. Iodobenzene (20 mg, 0.10
mmol) was added to the reaction mixture. The resulting
mixture was stirred at 708C for another 12 h. Workup
followed by column chromatography on silica gel to give 50
as a colorless oil (15 mg, 71% yield). Rf 0.60 (hexane/ethyl
acetate 9:1). 1H NMR (CDCl3) d 1.56 (m, 6H), 2.00 (m, 2H),
2.28 (m, 2H), 3.09 (d, J¼6.1 Hz, 2H), 4.95 (dd, J¼9.9,
2.0 Hz, 1H), 5.02 (d, J¼2.0 Hz, 1H), 5.69 (m, 1H), 7.26–
7.44 (m, 5H). 13C NMR (CDCl3) d 6.8, 28.4, 28.7, 30.7,
32.2, 38.5, 114.5, 125.7, 127.7, 128.8, 129.2, 136.4, 137.4,
143.8. IR (neat) 2924, 2853, 1489, 1443, 1234, 1070, 1026,
989, 908, 854, 700 cm21. MS m/z 213 (Mþþ1, 17), 212
(Mþ, 83), 211 (Mþ21, 6), 135 (100), 129 (47). HRMS
calcd for C16H20: Mþ, 212.1565. Found: m/z 212.1531.
Acknowledgments
This work was supported by a Grant-in-Aid for COE
Research on Elements Science, No. 12CE2005 from the
Ministry of Education, Culture, Sports, Science, and

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