Dramatic enhancement of reactivity of organosilicon compounds induced by complexation of bis(allyl)silanes with fluoride ion

Article abstract of DOI:10.1016/S0040-4020(00)00458-0

New type of fluoride ion catalyzed allylation agent (1a, 1b), allenylation agent (9, 10), and alkynylation agent (17) can be successfully utilized for various carbonyl substrates. The rate acceleration is ascribable to the shift of equilibrium to the chel

Full text of DOI:10.1016/S0040-4020(00)00458-0

TETRAHEDRON
Pergamon
Tetrahedron 56 (2000) 5373±5382
Dramatic Enhancement of Reactivity of Organosilicon
Compounds Induced by Complexation of Bis(allyl)silanes with
Fluoride Ion
Atsushi Shibato,b Yoshifumi Itagaki,b Eiji Tayama,b Yasutoshi Hokke,b Naoki Asaob
and Keiji Maruokaa,b,
*
aDepartment of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
bDepartment of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
Received 8 May 2000; accepted 29 May 2000
AbstractÐNew type of ¯uoride ion catalyzed allylation agent (1a, 1b), allenylation agent (9, 10), and alkynylation agent (17) can be
successfully utilized for various carbonyl substrates. The rate acceleration is ascribable to the shift of equilibrium to the chelate complexes
with Bu4NF by the favorable chelation of bis(silyl) compounds toward the ¯uoride ion. The 19F NMR spectrum (ethyl tri¯uoroacetate as
external standard) of a mixture of 1a and Bu4NF in CDCl3 showed two peaks at d 281.75 and 277.67 (integration ratio,9:1). The large
signal corresponds to the original peak of Bu4NF and the small one might be ascribed to the chelate complex [B] between 1a and Bu4NF. The
¯uoride ion mediated reaction of bis(crotyldimethylsilyl)methane (7) with benzaldehyde was examined and the only g-adduct 8 was obtained
regioselectively. q 2000 Elsevier Science Ltd. All rights reserved.
Introduction
generating allyl anion species via a chelate formation [B]
with Bu4NF (Eq. (2)), thereby allowing the hitherto
unattainable mild allylation with carbonyl compounds.12
In this paper we initially present a detailed study of the
reactivity of bis(allyl)silanes. We then turn our attention
to the extension of the present new activation method to
other bis(silyl) compounds having propargyl and alkynyl
group on silicon.
The ¯uoride ion-catalyzed reactions of reactive organo-
silicon compounds with carbonyl compounds have become
one of the most general and ef®cient carbon±carbon bond
formation methods under nearly neutral conditions available
to the synthetic organic chemist.1 The driving force of these
reactions seems to be an extremely high af®nity of ¯uoride
ion toward silicon atoms in organosilicon compounds as
expected from the high homolytic bond energy (132 kcal/
mol) of the Si±F linkage.2 The protonolysis of the Si±O
bond was initially reported3 and the ¯uoride-mediated
generation of nucleophiles has been exploited by the
desilylation of alkynylsilanes,4 allylic silanes,5,6 propargyl-
silanes,7 benzylsilanes,8 silyl enol ethers,9,10 and silyl ketene
acetals.11 Among these, the desilylation condition of allylic
silanes is not mild enough (THF re¯ux) for sensitive
functional group compatibility within a molecule. This is
mainly due to the mobile equilibrium between the parent
allylic silanes and their unfavorable complexes with Bu4NF
(Eq. (1)). In this context, we have been interested for some
time in the possibility of generating allyl anion species from
certain allylic silanes with Bu4NF catalyst under mild
reaction conditions without affecting other sensitive
functional groups. Recently we have communicated that
some bis(allyl)silanes of type [A] are highly effective for
ꢀ1†
ꢀ2†
Results and Discussion
A. Preparation of bis(allylsilyl) compounds
o-Bis(allyldimethylsilyl)benzene (1a) was synthesized by
treatment of o-bis(dimethylsilyl)benzene13 with Br2 (2
equiv.) followed by allylmagnesium bromide (2.2 equiv.)
in 75% yield. Bis(allyldimethylsilyl)methane (1b) and 1,3-
bis(allyldimethylsilyl)propane (1d) were prepared by
aluminum chloride catalyzed double chlorination of the
Keywords: ¯uoride ion; organosilicon compounds; bis(allyl)silanes.
* Corresponding author. Tel.: 181-0-75-753-4041; fax: 181-0-75-753-
4041; e-mail: maruoka@kuchem.kyoto-u.ac.jp
0040±4020/00/$ - see front matter q 2000 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)00458-0

5374
A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
Scheme 1. (a) Br2 (2 equiv.), CH2Cl2, 2788C!rt; (b) allylmagnesium bromide (2.2 equiv.), ether, 2788C; (c) cat. AlCl3, TMSCl; (d) cat. Pd(PPh3)4, 1,2-
dichlorotetramethyldisilane; (e) Me2SiHCl (2 equiv.), Mg (2 equiv.); (f) TMSCl, Li; (g) (i) MeMgBr (1 equiv.), ether, 2788C, (ii) allylmagnesium bromide
(1.2 equiv.), ether, 2788C.
corresponding 1,v-bis(trimethylsilyl)alkane with chloro-
trimethylsilane14 followed by allylation with allylmag-
nesium bromide (2.2 equiv.) in 93 and 59%, respectively.
As for 1,2-bis(allyldimethylsilyl)ethane (1c), the commer-
cially available 1,2-bis(chlorodimethylsilyl)ethane was
directly used (94% yield). cis-a,b-Bis(allyldimethylsilyl)-
styrene (1e) was obtained from the palladium catalyzed
double silylation of phenylacetylene using 1,2-dichloro-
tetramethyldisilane15 followed by allylmagnesium bromide
(3.6 equiv.) in 39% yield. For preparation of 1-allyl-
duced by treatment of 2-bromobenzyl bromide with chloro-
dimethylsilane (2.1 equiv.) in the presence of magnesium
(2.1 equiv.) in 91% yield. Then it was treated with Br2
(2 equiv.) followed by allylmagnesium bromide
(2.2 equiv.) to afford 1f in 23% yield. To obtain 1,3-
diallyl-1,1,2,2,3,3-hexamethyltrisilane (1g), octamethyl-
trisilane was prepared according to the literature (45%
yield).16 Then 1g was synthesized by aluminum chloride
catalyzed double chlorination of octamethyltrisilane,14
followed by allylation using allylmagnesium bromide
(2.2 equiv.) (45% yield). 1-Allyldimethylsilyl-2-trimethyl-
silylbenzene (1h) was prepared in 63% yield by treatment of
o-bis(dimethylsilyl)benzene with Br2 (2 equiv.) followed by
methylmagnesium bromide (1 equiv.) and allylmagnesium
bromide (1.2 equiv.) successively (Scheme 1). The mono-
silyl derivative, allyldimethylphenylsilane (2), was prepared
by the standard method [chlorodimethylphenylsilane and
allylmagnesium bromide] in high yield.
dimethylsilyl-2-(allyldimethylsilylmethyl)benzene (1f),
1-dimethylsilyl-2-(dimethylsilylmethyl)benzene was pro-
Table 1. Allylation of benzaldehyde with bis(silyl) compounds, 1a±h in the
presence of 5 mol% Bu4NF (the reaction was carried out using bis(allyl-
dimethylsilyl) compound (1.1 equiv.) and benzaldehyde (1.0 equiv.) at 08C
for 1 h)
Entry
Bis(silyl) compound
Yield of 3 (%)a
1
2
3
4
5
6
7
8
1a
1b
1c
1d
1e
1f
100
100
53
25
53
60
0
B. Reactions of bis(allylsilyl) compounds
o-Bis(allyldimethylsilyl)benzene (1a) was initially selected
to observe any chelation effect with Bu4NF catalyst.
Reaction of 1a with benzaldehyde in the presence of
5 mol% Bu4NF in THF at 08C proceeded smoothly within
1 h to furnish allylation product 3 quantitatively (Eq. (3)). In
contrast, 1 and 2 equiv. of allyldimethylphenylsilane (2)
1g
1h
33
a Isolated yield.

A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
5375
Table 2. Allylation of various aldehydes 4 with bis(allyl)silane 1a and 1b in the presence of 5 mol% Bu4NF in THF (the reaction was carried out using
bis(allyldimethylsilyl) compound (1a or 1b) (1.1 equiv.) and aldehydes 4 (1.0 equiv.))
Entry
Bis(allyl)silane R
Aldehyde 4
Condition (8C, h)
Yield of 5 (%)a
1
2
3
4
5
6
7
8
9
1a
1a
1b
1a
1a
1b
1a
1a
1b
p-MeOC6H4
p-FC6H4
p-FC6H4
b-naphtyl
CH3(CH2)5
CH3(CH2)5
C6H11
0, 4
rt, 0.6
0, 2
rt, 0.3
rt, 4
rt, 3
0, 4
85
99
89
98
32
34
35
40
49
PhCHvCH
PhCHvCH
0, 4
rt, 3
a Isolated yield.
upon reaction with benzaldehyde under similar reaction
conditions afforded 3 in only 4 and 7% yields, respec-
tively.17,18 Clearly, the rate acceleration with bis(silyl)
compound 1a is ascribable to the shift of equilibrium to
the complex [B] with Bu4NF by the favorable chelation of
bis(silane) toward the ¯uoride ion as shown in Eq. (2).19
conditions (entries 5±9).
ꢀ4†
Before cleavage of the silicon±oxygen bond by HCl/MeOH,
the allylation products have still one allyl group on silicon.
To clarify the reactivity of allylation products, we prepared
the allylation product 6 from the reaction of 1a with benz-
aldehyde without cleavage of silicon±oxygen bond in 80%
yield and examined the reaction of 6 with p-methoxy-
benzaldehyde in the presence of 5 mol% Bu4NF. 1-p-Meth-
oxylphenyl-3-buten-1-ol was not obtained at all but the
small amount of 1-phenyl-3-buten-1-ol was produced by
cleavage of silicon±oxygen bond of 6. This result clearly
showed that the reactivity of 6 was quite low under the
above condition and only one of two allyl groups of 1 trans-
ferred to aldehydes in the reaction of 1 with aldehydes
(Scheme 2).
ꢀ3†
We then evaluated the chelation effect of 1b±h with Bu4NF
catalyst by allylating benzaldehyde under the above
conditions. The results, summarized in Table 1, showed
bis-(allyl)silane 1a and 1b to be most satisfactory (entries
1 and 2). The reactions of 1c±f were sluggish and allylation
products were obtained in moderate yield (entries 3±6). No
reaction occurred in the reaction of 1g (entry 7). Notably,
switching one allyldimethylsilyl group in 1a by the
trimethylsilyl group signi®cantly lowered the yield of allyl-
ation product 3 (entry 8). Due to the relatively high electron-
withdrawing property of allyl group compared to methyl,
the allylsilyl moiety has stronger Lewis acidity than methyl-
silyl, and hence 1a possessing two allylsilyl groups probably
has higher af®nity toward the ¯uoride ion than 1h.
C. 19F NMR study
The possibility of the chelate complex formation of 1a with
¯uoride ion like [B] was also examined by 19F NMR
analysis. The spectra of Bu4NF and a mixture of Bu4NF
and 2 in CDCl3 did not show any noticeable difference in
chemical shifts. The original F signal in Bu4NF appeared at
d 281.98 and, upon addition of 1 equiv. of 2, the signal
shifted slightly to d 282.01 (ethyl tri¯uoroacetate as
external standard). However, the spectrum of the mixture
of 1a and Bu4NF showed two peaks at d 281.75 and
277.67, respectively (integration ratio,9:1). The large
signal corresponds to the original peak of Bu4NF and the
small one might be ascribed to the complex formation
With this information at hand, the allylation reactions
of o-bis(allyldimethylsilyl)benzene (1a) and bis(allyl-
dimethylsilyl)methane (1b) with several aldehydes 4 were
then carried out as listed in Table 2. Allylations of aromatic
aldehydes proceeded smoothly at 08C to room temperature
to give the corresponding homoallyl alcohol 5 in high yields
(entries 1±4). However, reactions of aliphatic and
a,b-unsaturated aldehydes were sluggish under similar
Scheme 2.

5376
A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
Scheme 3.
between 1a and Bu4NF. The small peak at d 277.67 also
implies that the equilibrium in Eq. (2) largely shifts to the
decomplexation at room temperature, and a small quantity
(,10%) of the Bu4NF/1a complex participates in the allyl-
ation reaction.
with respect to [1,3] sigmatropic shift of the silyl group
under the severe reaction conditions as mentioned above
(Scheme 5).5
We decided to examine the reaction of bis(crotylsilyl)
compound with benzaldehyde and clarify the regio- and
stereoselectivity of bis(silanes). The synthesis of desired
bis((E)-crotyldimethylsilyl)methane (7) follows: Cuprous
chloride-catalyzed condensation of trichlorosilane with
(E)-crotyl chloride, and subsequent treatment with methyl-
lithium (2 equiv.) gave (E)-crotyldimethylsilyl chloride
(46% yield), which was reacted with Mg and dibromo-
methane to afford 7 as a sole product in 49% yield (Scheme
6).
D. Preparation and reaction of bis(crotylsilyl)
compounds
The Lewis acid mediated reactions of allylic silanes with
aldehydes were known to proceed through an acyclic tran-
sition state and the mechanism was con®rmed from the
stereochemical outcome of the reaction using crotylsilanes.
For example, (E)-crotyltrimethylsilanes produces the syn-
alcohol in 97% diastereoselectivity upon treatment with
isobutyraldehyde±TiCl4 complex, and (Z)-crotyltrimethyl-
silane also affords the syn-alcohol as a major product (64%
selectivity) (Scheme 3).20
Since the reaction of 7 with benzaldehyde in the presence of
5 mol% Bu4NF was sluggish even at room temperature, the
reaction was carried out using stoichiometric amount of
Bu4NF at 08C and only the branched product 8 was obtained
in 40% yield. This result implied that the [1,3] sigmatropic
shift of the silyl group was suppressed in the reaction of 7.
The diastereomeric ratio of syn and anti was found to be
54:46 and this result showed that the reaction proceeded
through both the acyclic transition state (for example [C])
and the cyclic transition state (for example [D]) at
random.23,24
On the other hand, the pentacoordinate allylsilicates react
with aldehydes via a six-membered cyclic transition state,
and (E)-crotylsiliconates give anti-homoallyl alcohols,
whereas (Z)-isomers afford syn-homoallyl alcohols (Scheme
4).21
Additionally, the ¯uoride ion catalyzed reactions of crotyl-
tri¯uorosilanes were reported to proceed via the cyclic
transition state.22 On the other hand, the reactions of crotyl-
trimethylsilane with aldehyde are known to be not regio-
speci®c and the linear allylation product, which was
produced by bonding between aldehyde-carbon and
g-carbon of crotylsilane, was obtained predominantly over
the branched one, which was produced by bonding between
aldehyde-carbon and g-carbon of crotylsilane, probably
because the hypervalent intermediate is no longer stable
ꢀ5†
Preparation and reactions of bis(propargylsilyl)
compounds
These results encouraged us to extend this activation
method to other reactive organosilicon compounds. Pro-
pargylsilanes are known to react with carbonyl compounds
Scheme 4.
Scheme 5.

A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
5377
in the presence of catalytic amounts of ¯uoride ion.7 Based
on the results of bis(allylsilyl) compound, bis(propargyl-
silyl)methane (9) and 1,2-bis(propargylsilyl)benzene (10)
were synthesized in analogy to 1b and 1a in 48 and 54%
yields, respectively. The corresponding monosilyl deriva-
tives, propargyltrimethylsilane (11) and dimethylphenyl-
propargylsilane (12), were prepared by the standard
method in 18 and 63% yields, respectively.
ꢀ6†
ꢀ7†
Preparation and reactions of bis(alkynylsilyl)
compounds
In order to apply the present methodology to alkynylsilanes,
we next prepared bis[dimethyl(phenylethynyl)silyl]methane
(17) from bis(trimethylsilyl)methane in analogy to 1b in
64% yield and the monosilyl analog, 1-phenyl-2-(trimethyl-
silyl)acetylene (18), by the standard method, and examined
the reactions of 17 and 18 with cyclohexanone, respectively,
in the presence of 5 mol% Bu4NF at 2788C for 4 h. The
bis(silyl) compound 17 showed moderate reactivity and the
alkynylation product 19 was obtained in 54% yield. On
the other hand, the monosilyl reagent 18 gave 19 in only
19% yield under similar reaction conditions. These results
clari®ed that the reactivity of alkynylsilanes could be
increased by using bis(silyl) compound 17.
Attempted reaction of propargyltrimethylsilane (11) with
benzaldehyde in the presence of 5 mol% Bu4NF in THF at
2458C for 10 min gave no products. In contrast, 9 upon
reaction with benzaldehyde under similar conditions
afforded the mixture of allenylation product 13, propargyl-
ation product 14, and enyne compound 15 in the ratio of
71:22:7 and the chemical yield was quantitative (Eq. (6)).
Product 15 was probably formed by dehydration reaction of
propargylation product 14. The regioselectivity in the
reaction of propargylsilanes have been reported to depend
on the kinds of aldehydes, i.e. allenylation products were
obtained from aliphatic aldehydes and mixture of allenyl-
ation and propargylation products were produced from
aromatic aldehydes.7 The similar results were obtained in
the reactions using 10 and 12. The reaction of 10 with
heptanal catalyzed by Bu4NF in THF at 2258C for 7 min
gave allenylation product 16 in 55% yield. On the other
hand, allenylation product 16 was obtained in lower yield
(12%) in the reaction of the corresponding monosilyl
reagent, dimethylphenylpropargylsilane (12), under similar
reaction conditions (Eq. (7)). Interestingly, the reactivities
of these compounds somewhat depended on the ¯uoride ion
source. The reaction of 10 with heptanal catalyzed by
5 mol% Bu4N(Ph3SnF2) in THF at rt for 11 h gave 16 in
43% yield.25 On the contrary, allenylation product was not
obtained at all with 12 under similar reaction conditions.
Thus, the dramatic differences in chemical yield
between bis(propargylsilyl) reagents and monosilyl
reagents provide strong evidence for the existence of
the chelate complex [B] not only in the reactions of bis-
(allylsilyl) compounds but also in the reactions of bis(pro-
pargylsilyl) reagents.
ꢀ8†
Conclusions
In summary, we have developed new types of ¯uoride
Scheme 6. (a) Crotyl chloride, Et3N, cat. CuCl, ether, rt. (b) MeLi, ether, 2788C. (c) Mg, dibromomethane, THF, rt.

5378
A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
ion-catalyzed allylation agents, o-bis(allyldimethylsilyl)-
benzene (1a) and bis(allyldimethylsilyl)methane (1b), alle-
nylation agent, bis(dimethylpropargylsilyl)methane (9) and
o-bis(dimethylpropargylsilyl)benzene (10), and alkynyl-
ation agent, bis[dimethyl(phenylethynyl)silyl]methane
(17). The reactions using such bis(silyl) compounds proceed
much faster than those with monosilyl counterparts due to
the preferable formation of the chelate complex [B] (Eq.
(2)) by the chelation effect of two neighboring silicon
atoms and various data presented in this article imply the
high synthetic potential of our new methodology in organo-
silicon chemistry.
was increased to distill unreacted chlorotrimethylsilane.
The residue was diluted with THF (45 mL) and the solution
was cooled to 2788C. A 1.0 M ethereal solution of allyl-
magnesium bromide (33.0 mL, 33 mmol) was added, and
the mixture was stirred at 2788C for 30 min and at room
temperature for additional 30 min. The solution was
quenched with saturated NH4Cl and extracted with ether.
The organic extract was dried over Na2SO4. Evaporation
of solvent and puri®cation of the residual oil by column
chromatography on silica gel (hexane as eluent) gave bis-
(allyldimethylsilyl)methane (1b) (2.96 g, 14 mmol, 93%
1
yield) as a colorless oil: H NMR (CDCl3) d 5.70±5.86
(2H, m, 2CHvCH2), 4.80±4.86 (4H, m, 2CHvCH2),
1.51 (4H, d, Jˆ8.1 Hz, 2CH2CvC), 0.03 (12H, s, 4CH3),
20.25 (2H, s, SiCH2Si); IR (liquid ®lm) 3078, 2955, 2897,
1632, 1254, 1155, 1057, 893, 933 cm21; MS: m/z 197
(M12Me), 171 (100%), 155, 131, 129, 73. Anal. Calcd
for C11H24Si2: C, 62.17; H, 11.38. Found: C, 61.91; H,
11.27.
Experimental
General
Infrared (IR) spectra were recorded on a Shimazu FT-IR
8100A spectrometer. 1H, 13C and 19F spectra were measured
on a Varian Gemini-300 (300 MHz). All experiments were
carried out under an atmosphere of dry argon. For thin layer
chromatography (TLC) analysis throughout this work,
1,2-Bis(allyldimethylsilyl)ethane (1c).27 To a solution of
1,2-bis(chlorodimethylsilyl)ethane (2.15 g, 10 mmol) in
THF (20 mL) was added a 1.0 M ethereal solution of allyl-
magnesium bromide (22.0 mL, 22 mmol) at 2788C under
argon. The mixture was stirred at 2788C for 30 min and at
room temperature for additional 30 min. The solution was
quenched with saturated NH4Cl and extracted with ether.
The organic extract was dried over Na2SO4. Evaporation
of solvent and puri®cation of the residual oil by column
chromatography on silica gel (hexane as eluent) gave 1,2-
bis(allyldimethylsilyl)ethane (1c) (2.14 g, 9.4 mmol, 94%
Merck precoated TLC plates (silica gel 60 GF254
,
0.25 mm) were used. The products were puri®ed by prepara-
tive column chromatography on silica gel (E. Merck 9385).
Microanalyses were accomplished at the Center of Instru-
mental Analysis, Hokkaido University. The high-resolution
mass spectra (HRMS) were conducted at the School of
Agriculture, Hokkaido University.
1
In experiments requiring dry solvents, ether and tetrahydro-
furan (THF) were purchased from Kanto Chemical Co.
Ltd as `Dehydrated'. A 1 M THF solution of Bu4NF was
yield) as a colorless oil: H NMR (CDCl3) d 5.70±5.85
(2H, m, 2CHvCH2), 4.79±4.89 (4H, m, 2CHvCH2),
1.52 (4H, d, Jˆ8.4 Hz, 2CH2CvC), 0.41 (4H, s,
SiCH2CH2Si), 20.03 (12H, s, 4CH3).
Ê
stored over 4 A molecular sieves.
1,3-Bis(allyldimethylsilyl)propane (1d). Following the
same procedure for 1b, the double chlorination of 1,3-
bis(trimethylsilyl)propane (1.37 g, 7.3 mmol) with catalytic
aluminum chloride (0.097 g, 0.73 mmol) and chlorotri-
methylsilane (8.00 mL, 63 mmol), followed by allylation
with a 1.0 M ethereal solution of allylmagnesium bromide
(16.0 mL, 16 mmol) gave 1,3-bis(allyldimethylsilyl)pro-
pane (1d) (1.03 g, 4.3 mmol, 59% yield) as a colorless oil:
1H NMR (CDCl3) d 5.70±5.86 (2H, m, 2CHvCH2), 4.78±
4.89 (4H, m, 2CHvCH2), 1.51 (4H, d, Jˆ8.1 Hz,
2CH2CvC), 1.29±1.40 (2H, m, CH2C±Si), 0.58 (4H, t,
Jˆ8.4 Hz, 2CH2Si), 20.02 (12H, s, 4CH3); IR (liquid
Preparation of bis(allylsilyl) compounds
o-Bis(allyldimethylsilyl)benzene (1a).26 To a solution of
1,2-bis(dimethylsilyl)benzene (3.89 g, 20 mmol) in
CH2Cl2 (40 mL) was added Br2 (2.06 mL, 40 mmol) at
2788C under argon and the mixture was stirred for
30 min at 2788C. CH2Cl2 was evaporated in vacuo and
the residue was diluted with THF (40 mL). The solution
was cooled to 2788C. Then a 1.0 M ethereal solution of
allylmagnesium bromide (44.0 mL, 44 mmol) was added,
and the mixture was stirred at 2788C for 30 min and at
room temperature for additional 30 min. The solution was
quenched with saturated NH4Cl and extracted with ether.
The organic extracts were dried over Na2SO4. Evaporation
of solvent and puri®cation of the residual oil by column
chromatography on silica gel (hexane as eluent) gave
o-bis(allyldimethylsilyl)benzene (1a) (4.12 g, 15 mmol,
®lm) 3078, 2955, 2912, 1630, 1252, 1155, 905, 837 cm21
;
MS: m/z 240 (M1), 225, 212, 199, 157, 125, 99 (100 %), 73.
Anal. Calcd for C13H28Si2: C, 64.91; H, 11.73. Found: C,
64.80; H, 11.76.
1
cis-a,b-Bis(allyldimethylsilyl)styrene (1e). A mixture of
1,2-dichlorotetramethyldisilane (0.97 mL, 6 mmol), phenyl-
acetylene (0.55 mL, 5 mmol), and tetrakis(triphenyl-
phosphine)palladium, Pd(PPh3)4 (0.29 g, 0.25 mmol) was
heated at 1108C (oil bath) with magnetic stirring for 1.5 h.
The resulting mixture was diluted with THF (10 mL) and
the solution was cooled to 2788C. A 1.0 M ethereal solution
of allylmagnesium bromide (18 mL, 18 mmol) was added,
and the mixture was stirred at 2788C for 30 min and at room
temperature for additional 30 min. The solution was
75% yield) as a colorless oil: H NMR (CDCl3) d 7.30±
7.38 and 7.61±7.69 (4H, m, C6H4), 5.71±5.86 (2H, m,
2CHvCH2), 4.86±4.93 (4H, m, 2CHvCH2), 1.85 (4H, d,
Jˆ7.8 Hz, 2CH2Si), 0.38 (12H, s, 4CH3).
Bis(allyldimethylsilyl)methane (1b). A mixture of bis(tri-
methylsilyl)methane (3.20 mL, 15 mmol), chlorotrimethyl-
silane (16.5 mL, 130 mmol) and anhydrous aluminum
chloride (200 mg, 1.5 mmol) under argon was heated to
gentle re¯ux. After ca. 4 h, the temperature of the ¯ask

A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
5379
quenched with saturated NH4Cl and extracted with ether.
The organic extract was dried over Na2SO4. Evaporation
of solvent and puri®cation of the residual oil by column
chromatography on silica gel (hexane as eluent) gave cis-
a,b-bis(allyldimethylsilyl)styrene (1e) (0.56 g, 1.9 mmol,
(10.0 mL, 10 mmol) and then a 1.0 M ethereal solution of
allylmagnesium bromide (12.0 mL, 12 mmol): 1H NMR
(CDCl3) d 7.61±7.70 (2H, m, 2Ar±H), 7.29±7.36 (2H, m,
2Ar±H), 5.72±5.87 (1H, m, CHvCH2), 4.85±4.93 (2H, m,
CHvCH2), 1.85 (2H, d, Jˆ8.1 Hz, CH2Si), 0.37 (15H, s,
5CH3); IR (liquid ®lm) 3854, 3649, 2953, 1717, 1684, 1558,
1508, 1250, 1155, 1119, 839, 737 cm21. MS: m/z 248 (M1),
233, 217, 207, 191 (100%), 159, 135, 73. Anal. Calcd for
C14H24Si2: C, 67.66; H, 9.73. Found: C, 67.29; H, 9.77.
1
39% yield) as a colorless oil: H NMR (CDCl3) d 7.23±
7.31 (2H, m, 2Ph±H), 7.15±7.22 (1H, m, Ph±H), 6.99±7.05
(2H, m, 2Ph±H), 6.44 (1H, s, vCH±Si), 5.58±5.89 (2H, m,
2CHvCH2), 4.77±4.91 (4H, m, 2CHvCH2), 1.68 (2H, d,
Jˆ8.1 Hz, CH2Si), 1.61 (2H, d, Jˆ7.8 Hz, CH2Si), 0.23
(6H, s, 2CH3), 0.17 (6H, s, 2CH3); IR (liquid ®lm) 3076,
2957, 2897, 1630, 1256, 1153, 895, 820, 700 cm21; MS: m/z
300 (M1), 285, 259 (100 %), 217, 185, 159, 135, 99. Anal.
Calcd for C18H28Si2: C, 71.92; H, 9.38. Found: C, 71.71; H,
9.46.
Preparation of bis(crotylsilyl) compound
Bis(crotyldimethylsilyl)methane (7). To a mixture of
cuprous chloride (107 mg, 1.08 mmol) and triethylamine
(5.36 mL, 38.5 mmol) in ether (22 mL) were added crotyl
chloride (2.95 g, 32.5 mmol) and trichlorosilane (4.71 mL,
46.7 mmol) at room temperature under argon. The mixture
was stirred at room temperature for 4 h. Then, this mixture
was ®ltered with Celite and washed with ether. Distillation
of the concentrated ®ltrate gave trichlorocrotylsilane
(2.83 g, 14.9 mmol, 46% yield) as a colorless oil (bp 678C
at 62 mmHg).
1-Allyldimethylsilyl-2-(allyldimethylsilylmethyl)benzene
(1f). To a mixture of Mg (1.02 g, 42 mmol) and chlorodi-
methylsilane (5.33 mL, 42 mmol) in THF (20 mL) was
added a solution of 2-bromobenzyl bromide (5.00 g,
20 mmol) in THF (20 mL) dropwise at 08C under argon.
The mixture was stirred for 2 h at room temperature. The
solution was then quenched with saturated NH4Cl and
extracted with ether. The organic extract was dried over
Na2SO4. Evaporation of solvent and puri®cation of the
residual oil by column chromatography on silica gel (hexane
as eluent) gave 1-dimethylsilyl-2-(dimethylsilylmethyl)-
benzene as a precursor of 1f (3.78 g, 18 mmol, 91% yield
as a colorless oil). Following the same procedure for 1a,
1-dimethylsilyl-2-(dimethylsilylmethyl)benzene was treated
with Br2 (1.85 mL, 36.0 mmol) followed by a 1.0 M
ethereal solution of allylmagnesium bromide (39.6 mL,
39.6 mmol) to afford 1f (1.19 g, 4.1 mmol, 23% yield) as
To a solution of trichlorocrotylsilane (2.83 g, 14.9 mmol) in
ether (30 mL) was added a 1.14 M ethereal solution of
methyllithium (24.9 mL, 28.4 mmol) at 2788C under
argon. The mixture was stirred at 2788C for 2.5 h. Then,
this mixture was ®ltered with Celite and washed with ether.
Distillation of the concentrated ®ltrate gave chlorocrotyl-
dimethylsilane (1.16 g, 7.89 mmol, 53% yield) as a color-
less oil (bp 718C at 80 mmHg).
To a suspension of magnesium (102 mg, 4.2 mmol) in THF
(2 mL) was added chlorocrotyldimethylsilane (624 mg,
4.2 mmol) at room temperature under argon. Dibromo-
methane (140 mL, 2 mmol) was added dropwise at room
temperature and the whole mixture was stirred at room
temperature for 2 h and 708C for 19 h. The solution was
then quenched with saturated NH4Cl and extracted with
ether. The organic extract was dried over Na2SO4. Evapo-
ration of solvent and puri®cation of the residual oil by
column chromatography on silica gel (hexane as eluant)
gave bis(crotyldimethylsilyl)methane (7) (235 mg,
1
a colorless oil: H NMR (CDCl3) d 7.41 (1H, dd, Jˆ1.5,
7.5 Hz, Ar±H), 7.24 (1H, dt, Jˆ1.5, 7.5 Hz, Ar±H), 7.03±
7.11 (2H, m, 2Ar±H), 5.70±5.85 (2H, m, 2CHvCH2),
4.83±4.91 (4H, m, 2CHvCH2), 2.30 (2H, s, Ar±CH2Si),
1.81 (2H, d, Jˆ8.1 Hz, CH2CvC), 1.59 (2H, d, Jˆ8.1 Hz,
CH2CvC), 0.32 (6H, s, 2CH3), 0.01 (6H, s, 2CH3); IR
(liquid ®lm) 3076, 3057, 2957, 1630, 1587, 1250, 1155,
895 cm21; MS: m/z, 259, 247 (100 %), 231, 205, 173,
159, 145, 133, 99, 73. Anal. Calcd for C17H28Si2: C,
70.76; H, 9.08. Found: C, 70.41; H, 9.46.
1
2.1 mmol, 49% yield) as a colorless oil: H NMR (CDCl3)
1,3-Diallyl-1,1,2,2,3,3-hexamethyltrisilane (1g).28 Follow-
ing the same procedure for 1b, the double chlorination of
1,1,1,2,2,3,3,3-octamethyltrisilane (2.04 g, 10 mmol) with
catalytic aluminum chloride (133 mg, 1 mmol) and chloro-
trimethylsilane (11.9 mL, 93.8 mmol), followed by allyl-
ation with a 1.0 M ethereal solution of allylmagnesium
bromide (22.0 mL, 22 mmol) gave 1,3-diallyl-1,1,2,2,3,3-
hexamethyltrisilane (1g) (1.14 g, 4.4 mmol, 45% yield) as
d 5.32±5.44 (2H, m, 2CHvCHCH3), 5.18±5.29 (2H, m,
2CH2CHvCH), 1.64 (6H, dq, Jˆ1.2, 6.3 Hz,
2CvCHCH3), 1.38 (4H, dt, Jˆ1.2, 7.5 Hz, 2CH2CHvC),
0.00 (12H, s, 4SiCH3), 20.29 (2H, s, SiCH2Si); IR (liquid
®lm) 3012, 2956, 2929, 2856, 2362, 2341, 1508, 1400,
1377, 1305, 1251, 1161, 1055, 964, 837 cm21; MS(EI)
m/z 185 (M2CH2CHvCHCH3)1; HRMS(EI) Calcd for
C9H21Si2: 185.4367 (M2CH2CHvCHCH3)1. Found:
185.4341 (M2CH2CHvCHCH3)1.
1
a colorless oil: H NMR (CDCl3) d 5.70±5.86 (2H, m,
2CHvCH2), 4.80±4.89 (4H, m, 2CHvCH2), 1.61 (4H, d,
Jˆ9.0 Hz, 2CH2CvC), 0.12 (6H, s, 2CH3), 0.08 (12H, s,
4CH3).
Preparation of bis(propargylsilyl) compounds
Bis(dimethylpropargylsilyl)methane (9). Following the
procedure for 1b, the double chlorination of bis(trimethyl-
silyl)methane (6.41 mL, 30 mmol) with catalytic aluminum
chloride (400 mg, 3 mmol) and chlorotrimethylsilane
(33.0 mL, 260 mmol), and subsequent addition of a 1.0 M
ethereal solution of propargylmagnesium bromide
(66.0 mL, 66 mmol) gave bis(propargylsilyl)methane (9)
1-Allyldimethylsilyl-2-trimethylsilylbenzene (1h). Follow-
ing the same procedure for 1a, the title compound was
prepared in 63% yield (1.56 g, 6.3 mmol) as a colorless
oil by treatment of o-bis(dimethylsilyl)benzene (1.94 g,
10 mmol) with Br2 (1.03 mL, 20 mmol), followed by a
1.0 M THF solution of methylmagnesium bromide

5380
A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
1
(2.92 g, 14 mmol, 48% yield) as a colorless oil: H NMR
(CDCl3) d 1.84±1.86 (2H, t, Jˆ3.0 Hz, 2CCH), 1.50±1.51
(4H, d, Jˆ3.0 Hz, 2SiCH2CC), 0.169 (12H, s, 4SiCH3),
0.169 (2H, s, SiCH2Si); IR (liquid ®lm) 3313, 2956, 2895,
2115, 1398, 1255, 1155, 1058, 952, 837, 696 cm21; MS(EI)
m/z 193 (M2CH3)1; HRMS(EI) Calcd for C10H17Si2:
193.4159 (M2CH3)1. Found: 193.4120 (M2CH3)1.
0.05 mmol) at 08C under argon. After stirring for 1 h at this
temperature, the reaction was quenched by a mixture of
conc. HCl and MeOH (1:100) at 08C. Ether was added
and the mixture was washed with saturated NaHCO3 and
brine. The organic layer was dried, ®ltered, and concen-
trated. The residue was puri®ed by column chromatography
on silica gel using a mixture of hexane and EtOAc (6:1) as
eluent to give 1-phenyl-3-buten-1-ol (3) (148 mg, 100%
yield) as a colorless oil.
o-Bis(propargyldimethylsilyl)benzene (10). To a solution
of 1,2-bis(dimethylsilyl)benzene (5.83 g, 30 mmol) in
CH2Cl2 (60 mL) was added Br2 (3.09 mL, 60 mmol) at
2788C under argon. The mixture was stirred at 2788C for
30 min, and CH2Cl2 was evaporated in vacuo. The residue
was diluted with ether (50 mL), and cooled to 2788C. Then
a 1.0 M ethereal solution of propargylmagnesium bromide
(66.0 mL, 66 mmol) was added, and the mixture was stirred
at 2788C for 30 min and at room temperature for additional
30 min. The solution was quenched with saturated NH4Cl
and extracted with ether. The organic extract was dried over
Na2SO4. Evaporation of solvent and puri®cation of the
residual oil by column chromatography on silica gel (hexane
as eluent) gave o-bis(propargyldimethylsilyl)benzene (10)
(4.42 g, 16.3 mmol, 54% yield) as a colorless oil: 1H
NMR (CDCl3) d 7.67±7.73 (2H, m, 2Ar±H), 7.35±7.41
(2H, m, 2Ar±H), 1.88 (2H, t, Jˆ3.0 Hz, 2CuCH), 1.82
(4H, d, Jˆ3.0 Hz, 2CH2Si); 0.51 (12H, s, 4CH3); IR (liquid
®lm) 3294, 2957, 2116, 1414, 1254, 1150, 1121, 953, 841,
816, 745, 631, 451 cm21; MS: m/z 270 (M1), 255, 231
(100%), 215, 191, 177, 145, 133, 97, 73. Anal. Calcd
for C16H22Si2: C, 71.03; H, 8.19. Found: C, 70.81; H,
7.82.
1-Phenyl-3-buten-1-ol (3).29 1H NMR (CDCl3) d 7.25±
7.39 (5H, m, Ph), 5.75±5.89 (1H, m, CHvCH2), 5.13±
5.21 (2H, m, CHvCH2), 4.71±4.77 (1H, m, CH±O),
2.43±2.59 (2H, m, CH2CvC), 2.08 (1H, br s, OH).
1-(p-Methoxyphenyl)-3-buten-1-ol.29 1H NMR (CDCl3) d
7.28 (2H, d, Jˆ8.7 Hz, 2Ar±H), 6.89 (2H, d, Jˆ8.7 Hz,
2Ar±H), 5.74±5.87 (1H, m, CHvCH2), 5.12±5.20 (2H,
m, CHvCH2), 4.69 (1H, t, Jˆ6.3 Hz, CH±O), 3.81 (3H,
s, OCH3), 2.52 (2H, t, Jˆ6.3 Hz, CH2CvC), 2.00 (1H, br s,
OH).
1-(p-Fluorophenyl)-3-buten-1-ol.29 1H NMR (CDCl3) d
7.30±7.38 (2H, m, 2Ar±H), 7.00±7.08 (2H, m, 2Ar±H),
5.73±5.86 (1H, m, CHvCH2), 5.14±5.21 (2H, m,
CHvCH2). 4.73 (1H, t, Jˆ6.0 Hz, CH±O), 2.14±2.56
(2H, m, CH2CvC), 2.08 (1H, br s, OH).
1
1-(b-Naphthyl)-3-buten-1-ol. H NMR (CDCl2) d 7.79±
7.87 (4H, m, 4Ar±H), 7.45±7.51 (3H, m, 3Ar±H), 5.76±
5.90 (1H, m, CHvCH2), 5.13±5.23 (2H, m, CHvCH2),
4.88±4.93 (1H, m, CH±O), 2.51±2.68 (2H, m, CH2CvC),
2.20 (1H, br s, OH). Anal. Calcd for C14H14O: C, 84.81; H,
7.12. Found: C, 84.69; H, 7.21.
Bis((phenylethynyl)dimethylsilyl)methane (17). A mixture
of bis(trimethylsilyl)methane (1.06 mL, 5 mmol) and
chlorotrimethylsilane (635 mL, 5 mmol) was heated to
gentle re¯ux in the presence of anhydrous aluminum
chloride (66.7 mg, 0.5 mmol) under argon. After ca. 4 h,
the temperature of the ¯ask was increased to distill chloro-
trimethylsilane. The residue was diluted with THF (15 mL)
and the solution was cooled to 2788C. A 0.5 M THF
solution of lithium phenylacetylide (22.0 mL, 11 mmol)
was added, and the mixture was stirred at 2788C for
30 min and at room temperature for additional 30 min.
The solution was quenched with saturated NH4Cl and
extracted with ether. The organic extract was dried over
Na2SO4. Evaporation of solvent and puri®cation of the
residual oil by column chromatography on silica gel (hexane
as eluent) gave bis((phenylethynyl)dimethylsilyl)methane
1-Decen-3-ol.30 1H NMR (CDCl3) d 5.77±5.91 (1H, m,
CHvCH2), 5.11±5.18 (2H, m, CHvCH2), 3.61±3.69
(1H, m, CH±O), 2.09±2.35 (2H, m, CH2CvC), 1.61 (1H,
br s, OH), 1.16±1.48 (10H, m, 5CH2), 0.89 (3H, t,
Jˆ6.9 Hz, CH3).
1-Cyclohexyl-3-buten-1-ol.30 1H NMR (CDCl3) d 5.78±
5.92 (1H, m, CHvCH2), 5.12±5.19 (2H, m, CHvCH2),
3.36±3.43 (1H, m, CH±O), 2.07±2.38 (2H, m, CH2CvC),
1.61±1.90 (5H, m, CH12CH2), 1.58 (1H, br s, OH), 0.95±
1.42 (6H, m, 3CH2).
(E)-1-Phenyl-1,5-hexadien-3-ol.29 1H NMR (CDCl3) d
7.22±7.41 (5H, m, Ph), 6.61 (1H, d, Jˆ15.6 Hz, PhCH),
6.25 (1H, dd, Jˆ15.9 Hz, PhCvCH), 5.79±5.93 (1H, m,
CHvCH2), 5.15±5.23 (2H, m, CHvCH2), 4.35±4.38
(1H, m, CH±O), 2.33±2.50 (2H, m, CH2CvC), 1.85 (1H,
br s, OH).
1
(17) (1.07 g, 3.2 mmol, 64% yield) as an orange oil: H
NMR (CDCl3) d 7.43±7.48 (4H, m, Ph±H), 7.27±7.32
(6H, m, Ph±H), 0.35 (12H, s, 4CH3), 0.17 (2H, s, CH2);
IR (liquid ®lm) 3080, 2959, 2901, 2158, 1489, 1443,
1250, 1221, 1055, 1028, 853, 823, 756, 691, 536 cm21
;
MS: m/z 332 (M1), 317, 245, 215, 159 (100%), 143, 129,
105, 73. Anal. Calcd for C21H24Si2: C, 75.83; H, 7.27.
Found: C, 75.67; H, 7.40.
1
Allylation product 6. H NMR (CDCl3) d 7.63±7.68 (2H,
m, 2Ar±H), 7.22±7.36 (7H, m, 2Ar±H1Ph), 5.55±5.86
(2H, m, 2CHvCH2), 4.82±5.01 (4H, m, 2CHvCH2),
4.76 (1H, t, Jˆ6.9 Hz, PhCH), 2.49±2.71 (2H, dd,
CH2CvC), 1.92 (2H, d, Jˆ7.8 Hz, CH2CvC), 0.35±0.42
(9H, m, 3CH3), 0.18 (3H, s, CH3); IR (liquid ®lm) 3074,
3045, 2955, 2903, 2361, 1630, 1454, 1418, 1252, 1119,
1080, 1059, 1042, 930, 835, 764, 700 cm21; MS: m/z,
332, 317, 265, 233, 209, 193, 149, 131 (100 %), 91, 73.
Reactions of bis(allylsilyl) compounds
General procedure for the allylation of aldehydes with
bis(allylsilyl) compounds. To a solution of 1a (0.32 mL,
1.1 mmol) and benzaldehyde (0.10 mL, 1.0 mmol) in THF
(2 mL) was added a 1 M THF solution of Bu4NF (0.05 mL,

A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
5381
Anal. Calcd for C23H32OSi2: C, 72.56; H, 8.47. Found: C,
72.24; H, 8.56.
Acknowledgements
This work was partially supported by the Asahi Glass
Foundation, the Akiyama Foundation, the Ogasawara
Foundation for the Promotion of Science and Engineering,
and a Grant-in-Aid for Scienti®c Research from the
Ministry of Education, Science, Sports and Culture, Japan.
19F NMR study
The 19F NMR analysis of Bu4NF in CDCl3/THF in the
absence or presence of allylic silanes (1a or 2) was carried
out using ethyl tri¯uoroacetate (dˆ0) as external standard.
References
Bu4NF: 19F NMR (CDCl3) d 281.98.
1. Fleming, I.; Barbero, A.; Walter, D. Chem. Rev. 1997, 97,
2063±2192.
An equimolar mixture of Bu4NF and allyldimethylphenyl-
silane (2): 19F NMR (CDCl3) d 282.01.
2. Farber, M.; Srivastava, R. D. J. Chem. Soc., Faraday Trans. 1
1978, 74, 1089±1095.
An equimolar mixture of Bu4NF and o-bis(allyldimethyl-
silyl)benzene (1a): 19F NMR (CDCl3) d 277.67 (chelate
complex [B]), 281.75 (integration ratio,1:9).
3. Corey, E. J.; Snider, B. B. J. Am. Chem. Soc. 1972, 94, 2549±
2550.
4. (a) Nakamura, E.; Kuwajima, I. Angew. Chem. Int. Ed. Engl.
1976, 15, 498±499. (b) Kuwajima, I.; Nakamura, E.; Hashimoto,
K. Tetrahedron 1983, 39, 975±982. (c) Holmes, A. B.; Jennings-
White, C. L. D.; Schulthess, A. H.; Akinde, B.; Walton, D. R. M.
J. Chem. Soc., Chem. Commun. 1979, 840±842.
Reaction of bis(crotylsilyl) compounds
syn-1-Phenyl-2-methyl-3-buten-1-ol (syn-8).24 1H NMR
(CDCl3) d 7.20±7.39 (5H, m, Ph), 5.52±5.72 (1H, m,
CHvCH2), 5.00±5.10 (2H, m, CHvCH2), 4.62 (1H, d,
Jˆ8.5 Hz, PhCH), 2.35±2.57 (1H, m, CH±CvC), 1.68
(1H, s, OH), 0.98 (3H, d, Jˆ8 Hz, CH3).
anti-1-Phenyl-2-methyl-3-buten-1-ol (anti-8).24 1H NMR
(CDCl3) d 7.21±7.40 (5H, m, Ph), 5.66±5.86 (1H, m,
CHvCH2), 5.15±5.26 (2H, m, CHvCH2), 4.34 (1H, d,
Jˆ8.5 Hz, PhCH), 2.35±2.53 (1H, m, CH±CvC), 1.62
(1H, s, OH), 0.86 (3H, d, Jˆ8 Hz, CH3).
5. Hosomi, A.; Shirahata, A.; Sakurai, H. Tetrahedron Lett. 1978,
3043±3046.
6. (a) Weber, W. P. Silicon Reagents for Organic Synthesis;
Springer-Verlag: Berlin, 1983; pp 391±404. (b) Fleming, I.;
Dunogues, J.; Smithers, R. Org. React. (N.Y.) 1989, 37, 57±575.
(c) Yamamoto, Y.; Asao, N. Chem. Rev. 1993, 93, 2207±2293.
7. Pornet, J. Tetrahedron Lett. 1981, 22, 455±456.
8. Bennetau, B.; Bordeau, M.; Dunogues, J. Bull. Soc. Chim. Fr.
1985, 90±93.
9. (a) Kuwajima, I.; Nakamura, E. J. Am. Chem. Soc. 1975, 97,
3257±3258. (b) Noyori, R.; Nishida, I.; Sakata, J. Tetrahedron
Lett. 1980, 21, 2085±2088.
10. (a) Noyori, R.; Yokoyama, K.; Sakata, J.; Kuwajima, I.;
Nakamura, E.; Shimizu, M. J. Am. Chem. Soc. 1977, 99, 1265±
1267. (b) Nakamura, E.; Shimizu, M.; Kuwajima, I.; Sakata, J.;
Yokoyama, K.; Noyori, R. J. Org. Chem. 1983, 48, 932±945.
11. (a) Nakamura, E.; Shimizu, M.; Kuwajima, I. Tetrahedron
Lett. 1976, 1699±1702. (b) RajanBabu, T. V. J. Org. Chem.,
1984, 49, 2083±2089.
Reaction of bis(propargylsilyl) compounds
1-Phenyl-2,3-butadien-1-ol (13).30 1H NMR (CDCl3) d
7.28±7.44 (5H, m, Ph), 5.45 (1H, td, Jˆ6.6, 6.6 Hz,
CHvC), 5.25±5.30 (1H, m, CH±O), 4.88±4.99 (2H, m,
CH2vC), 2.46 (1H, br s, OH).
12. Asao, N.; Shibato, A.; Itagaki, Y.; Fabrice, J.; Maruoka, K.
Tetrahedron Lett. 1998, 39, 3177±3180.
1-Phenyl-3-butyn-1-ol (14).30 1H NMR (CDCl3) d 7.28±
7.42 (5H, m, Ph), 4.89 (1H, dt, Jˆ3.3, 6.6 Hz, PhCH), 2.65
(2H, dd, Jˆ2.7, 6.6 Hz, CH2), 2.40 (1H, br d, Jˆ3.3 Hz,
OH), 2.08 (1H, t, Jˆ2.7 Hz, CuCH).
1-Phenyl-1-buten-3-yne (15).31 1H NMR (CDCl3) d 7.28±
7.41 (5H, m, Ph), 7.05 (1H, d, Jˆ16.5 Hz, PhCH), 6.14 (1H,
dd, Jˆ2.4, 16.5 Hz, CHvCHC), 3.06 (1H, d, Jˆ2.4 Hz,
CuCH).
13. Fink, W. Helv. Chim. Acta 1974, 57, 1010±1015.
14. Ishikawa, M.; Kumada, M.; Sakurai, H. J. Organomet. Chem.
1970, 23, 63±69.
15. Watanabe, H.; Kobayashi, M.; Higuchi, K.; Nagai, Y.
J. Organomet. Chem. 1980, 186, 51±62.
16. Gilman, H.; Harrell, R. L. J. Organomet. Chem. 1966, 5, 201±
202.
17. The reaction of benzaldehyde with allyltrimethylsilane
(1 equiv.) under similar conditions gave 14% yield.
18. Reaction of allyltrimethylsilane with various carbonyl
substrates in the presence of 5 mol% of Bu4NF in re¯uxing THF
is reported to produce allylation products in high yields (Ref. 5). In
our hands, treatment of allyltrimethylsilane with the same carbonyl
substrates (e.g. hydrocinnamaldehyde, cyclohexanone¼) gave the
allylation products in quite low yield. We used commercially avail-
able Bu4NF from Aldrich Chemical Co. by drying it with molecu-
1,2-Decadien-4-ol (16).30 1H NMR (CDCl3) d 5.24 (1H, dt,
Jˆ6.6, 6.6 Hz, vCH), 4.86 (2H, dd, Jˆ2.5, 6.6 Hz, vCH2),
4.12±4.22 (1H, m, CH±O), 1.87 (1H, br s, OH), 1.16±1.62
(10H, m, 5CH2), 0.87 (3H, t, Jˆ6.9 Hz, CH3).
1-(Phenylethynyl)-1-cyclohexanol (19). 1H NMR (CDCl3)
d 7.41±7.46 (2H, m, Ph±H), 7.29±7.33 (3H, m, Ph±H),
2.09 (1H, br s, OH), 1.21±2.06 (10H, m, 5CH2). The
authentic sample was independently prepared by treat-
ment of cyclohexanone with phenylethynyllithium in THF
at 08C.
Ê
lar sieves 4 A. On the other hand, Hosomi and Sakurai prepared
Bu4NF by themselves, thereby causing the different outcome
(private communication by Prof. Hosomi).
19. (a) Tamao, K.; Hayashi, T.; Ito, Y. J. Organomet. Chem. 1996,

5382
A. Shibato et al. / Tetrahedron 56 (2000) 5373±5382
506, 85±91. (b) Tamao, K.; Hayashi, T.; Ito, Y.; Shiro, M. Organo-
metallics 1992, 11, 2099±2114. (c) Tamao, K.; Hayashi, T.; Ito,
Y.; Shiro, M. J. Am. Chem. Soc. 1990, 112, 2422±2424.
20. Hayashi, T.; Kabeta, K.; Hamachi, I.; Kumada, M. Tetrahedron
Lett. 1983, 24, 2865±2868.
24. Hoffmann, R. W.; Zeiû, H.-J. J. Org. Chem. 1981, 46, 1309±
1314.
25. Gingras, M. Tetrahedron Lett. 1991, 32, 7381±7384.
26. Uhlig, W. Helv. Chim. Acta 1994, 77, 972±980.
27. Corriu, R.; Masse, J. Bull. Soc. Chim. Fr. 1974, 77, 3045±
3048.
21. (a) Kira, M.; Sato, K.; Sakurai, H. J. Am. Chem. Soc. 1988,
110, 4599±4602. (b) Hosomi, A.; Kohra, S.; Tominaga, Y. J. Chem.
Soc., Chem. Commun. 1987, 1517±1518. (c) Hayashi, T.;
Matsumoto, Y.; Kiyoi, T.; Ito, Y.; Kohra, S.; Tominaga, Y.;
Hosomi, A. Tetrahedron Lett. 1988, 29, 5667±5670.
22. (a) Kira, M.; Kobayashi, M.; Sakurai, H. Tetrahedron Lett.
1987, 28, 4081±4084. (b) Kira, M.; Hino, T.; Sakurai, H.
Tetrahedron Lett. 1989, 30, 1099±1102.
28. Guo, Y.; Xu, S.; Zhou, X. Gaodeng Xuexiao Huebao 1989, 10,
51±55.
29. Li, C.-J.; Meng, Y.; Yi, X.-H.; Ma, J.; Chan, T.-H. J. Org.
Chem. 1998, 63, 7498±7504.
30. Yu, C.-M.; Choi, H.-S.; Yoon, S.-K.; Jung, W.-H. Synlett
1997, 889±890.
31. Torrado, A.; Lopez, S.; Alvarez, R.; Lera, A. R. Synthesis
1995, 285±293.
23. The possibility of generating anti-8 via the acyclic transition
state is not totally excluded.