Lewis acid catalyzed highly regio- and stereocontrolled trans- hydrosilylation of alkynes and allenes

Article abstract of DOI:10.1021/jo9824293

Lewis acids such as AlCl₃ or EtAlCl₂ dramatically catalyzed the hydrosilylation of alkynes 1 with trialkylsilanes to produce the corresponding cis-vinylsilanes 2 in a regio- and trans-stereoselective manner. For example, the hydrosil

Full text of DOI:10.1021/jo9824293

2
494
J . Org. Chem. 1999, 64, 2494-2499
Lew is Acid Ca ta lyzed High ly Regio- a n d Ster eocon tr olled
Tr a n s-Hyd r osilyla tion of Alk yn es a n d Allen es
Tomoko Sudo, Naoki Asao, Vladimir Gevorgyan, and Yoshinori Yamamoto*
Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, J apan
Received December 11, 1998
3 2
Lewis acids such as AlCl or EtAlCl dramatically catalyzed the hydrosilylation of alkynes 1 with
trialkylsilanes to produce the corresponding cis-vinylsilanes 2 in a regio- and trans-stereoselective
manner. For example, the hydrosilylation of 1-dodecyne 1a with triethylsilane in the presence of
0
.2 equiv of AlCl
substituted terminal and internal acetylenes also underwent trans-hydrosilylation very smoothly.
In the case of alkoxy- or silyloxy-substituted acetylenes, the use of 1.2 equiv of AlCl or EtAlCl
was essential to obtain the corresponding trans-hydrosilylation products in high yields. Moreover,
AlCl catalyzed the hydrosilylation of aromatic allenes 11, producing the alkenylsilanes 12 with
3
gave cis-1-(triethylsilyl)-1-dodecene in 93% yield. Other alkyl- and phenyl-
3
2
3
high regio- and stereoselectivities in moderate to high chemical yields. Not only the simple
monosubstituted, but also the disubstituted and trisubstituted allenes, underwent the hydrosilyl-
ation reaction smoothly, serving as a useful tool for the synthesis of differently substituted
vinylsilanes which are not easily available through the previously known methodologies. The
mechanisms for these catalytic reactions of alkynes and allenes are proposed.
In tr od u ction
hydrosilylation of porous silicon, because transition metal
catalysts have the potential for activation of the weaker
Si-Si bonds, instead of Si-H bonds, on the surface. In
this paper, we detail the Lewis acid-catalyzed trans-
hydrosilylation reactions of acetylenes together with the
hydrosilylation of allenes.
The great versatility of vinylsilanes as building blocks
has been increased in modern synthetic organic chem-
1
2
istry. Hydrosilylation of alkynes is one of the simplest
and the most straightforward preparative methods to
obtain vinylsilanes. It is well-known that hydrosilylation
3
of alkynes is induced either by radical initiator or by
4
Resu lts a n d Discu ssion
transition metal catalysts. The radical-induced proce-
dure often provides a mixture of trans- and cis-hydrosi-
lylation products. Although the transition metal-cata-
lyzed reaction proceeds with high stereoselectivity via a
cis-hydrosilylation pathway, it usually produces a mix-
ture of two regioisomers (terminal and internal products)
in the reaction with terminal alkynes. Recently, we
reported that the hydrosilylation of alkynes 1 with
trialkylsilanes is catalyzed dramatically by Lewis acids
Alk yn es. The results of the Lewis acid-catalyzed
hydrosilylation of alkynes are summarized in Table 1.
First, we examined the hydrosilylation of 1-dodecyne (1a )
using triethylsilane with several different kinds of Lewis
acids. Lewis acid catalysts such as ZrCl
not effective for the hydrosilylation of 1-dodecyne (entries
and 2). This is in marked contrast with the observation
in the Lewis acid-catalyzed hydrostannation of 1a , in
4 4
and HfCl were
1
such as AlCl
3 2
and EtAlCl , leading to cis-alkenylsilanes
2
with very high regio- and stereoselectivities in good to
5
,6
high yields (eq 1). Although most hydrometalations of
alkynes proceed in a cis-manner, Lewis acid-catalyzed
hydrosilylation proceeds in a trans-manner. Quite re-
cently, our procedure was applied to the modification of
the surface of porous silicon by Buriak and Allene. They
stated that Lewis acid catalysts are suitable for the
3
(6) Although AlCl -catalyzed hydrosilylation of alkynes had been
7
reported by Voronkov’s group, detailed information on regio- and
stereoselectivities and generality of the reaction are not available: see
(a) Voronkov, M. G.; Adamovich, S. N.; Pukhnarevich, V. B. J . Gen.
Chem. USSR (Engl. Transl.) 1982, 52, 2058. (b) Voronkov, M. G.;
Adamovich, S. N.; Sherstyannikova, L. V.; Pukhnarevich, V. B. J . Gen.
Chem. USSR (Engl. Transl.) 1983, 53, 706. (c) Ulrich, F.; Hans, M.
W. Ger. Pat. 2,804,204, 1979; Chem. Abstr. 1979, 91, 193413x. (d)
Mackenzie, C. A.; Spialter, L.; Schoffman, M. Br. Pat. 684, 597, 1953;
Chem. Abstr. 1954, 2761d. (e) Hatcher, D. B. U.S. Pat. 2,555,589, 1971;
Chem. Abstr. 1951, 8814.
8
(1) (a) Colvin, E. W. Silicon Reagents in Organic Synthesis; Aca-
demic: London, 1988. (b) Weber, W. P. Silicon Reagents for Organic
Synthesis; Springer: Berlin, 1983. (c) Colvin, E. W. Silicon in Organic
Synthesis; Butterworth: London, 1981.
(7) (a) Hydroboration, see: Smith, K.; Pelter, A.; Brown, H. C.
Borane Reagents; Academic Press: London, 1988. Smith, K.; Pelter,
A. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.;
Pergamon Press: Oxford, 1991; Vol. 8, p 703. (b) Hydroalumination,
see: Sato, F. J anssen Chim. Acta 1990, 8, 3. Eisch, J . J . In Compre-
hensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon
Press: Oxford, 1991; Vol. 8, p 733. (c) Hydromagnesation, see: Sato,
F. J . Organomet. Chem. 1985, 285, 53. (d) Hydrostannation, see:
Pereyre, M.; Quintard, J .-P.; Rahm, A. Tin in Organic Synthesis;
Butterworths: London, 1987. (d) Hydrozirconation, see: Labinger, J .
A. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.;
Pergamon Press: Oxford, 1991; Vol. 8, p 667. (e) Hydrozincation, see:
Gao, Y.; Harada, K.; Hata, T.; Urabe, H.; Sato, F. J . Org. Chem. 1995,
60, 290.
(2) (a) Hiyama, T. Kusumoto, T. In Comprehensive Organic Syn-
thesis; Trost, B. M., Fleming, I., Eds.; Pergmon Press: Oxford, 1991;
Vol. 8, p 763. (b) Ojima, I. In The Chemistry of Organic Silicon
Compounds; Patai, S., Rappoport, Z., Eds.; J ohn Wiley: Chichester,
1
989; p 1479.
3) (a) Selin, T. G.; West, R. J . Am. Chem. Soc. 1962, 84, 1860. (b)
(
Benkeser, R. A.; Burrous, M. L.; Nelson, L. E.; Swisher, J . V. J . Am.
Chem. Soc. 1961, 83, 4385.
(4) Transition metal complexes derived from Pt, Ir, Pd, Rh, Ru, Ni,
Co, Fe, Re, and Mn metals have been used for hydrosilylation; see ref
2
.
(5) Asao, N.; Sudo, T.; Yamamoto, Y. J . Org. Chem. 1996, 61, 7654.
(8) Buriak, J . M.; Allen, M. J . J . Am. Chem. Soc. 1998, 120, 1339.
1
0.1021/jo9824293 CCC: $18.00 © 1999 American Chemical Society
Published on Web 03/05/1999

Trans-Hydrosilylation of Alkynes and Allenes
J . Org. Chem., Vol. 64, No. 7, 1999 2495
Ta ble 1. Lew is Acid -Ca ta lyzed Hyd r osilyla tion of
Alk yn es w ith HSiR3
Ta ble 2. Lew is Acid -Ca ta lyzed Hyd r osilyla tion of
1-Dod ecyn e 1a w ith HSiR3
entry Lewis acid (equiv)
R3SiH
product yield (%)
1
2
3
4
AlCl3 (0.2)
AlCl3 (0.2)
EtAlCl2 (0.2)a
t-BuMe2SiH
(c-C6H11)Me2SiH
Ph3SiH
2n
2o
2p
2q
2r
78
73
40
45
60
0
a
EtAlCl2 (0.2)
Ph2MeSiH
PhMe2SiH
3
5
EtAlCl2 (0.2)a
1
yield (%)a
Lewis acid
(equiv)
6b
AlCl (0.2)
(EtO) SiH
2s
3
entry
R1
R2
2
3
a
If AlCl3 was used in the hydrosilylation with the phenylsub-
1
2
3
4
ZrCl4 (0.2)
HfCl4 (0.2)
AlCl3 (0.2)
EtAlCl2 (0.2) CH3(CH2)9
Et2AlCl (0.2) CH3(CH2)9
AlCl3 (0.2)
AlCl3 (0.2)
AlCl3 (0.2)
AlCl3 (0.2)
EtAlCl2 (0.2) 1-cyclohexenyl
EtAlCl2 (0.2) Ph
EtAlCl2 (1.2) i-Pr3SiO(CH2)2
AlCl3 (1.2)
EtAlCl2 (1.2) PhCH2O(CH2)2
AlCl3 (0.2)
AlCl3 (0.2)
AlCl3 (0.2)
AlCl3 (0.2)
CH3(CH2)9
CH3(CH2)9
CH3(CH2)9
H
H
H
H
H
H
H
H
H
H
H
H
H
H
1a trace
1a 28
1a 93
1a 95
0
0
0
0
0
0
0
0
89
0
0
0
0
0
-
-
10
26
stituted silanes, the silylating reagents were decomposed partially
prior to adding to the acetylene 1a . b The starting material 1a was
recovered quantitatively.
b
5
1a
0
c
chemical difference in the hydrosilylation reaction of the
alkyl (1a -c) and silyl (1d ) substituted alkynes is very
interesting and is discussed in the mechanistic section.
The reactions of conjugated enynes, 1-ethynyl-1-cyclo-
hexene 1e and phenylacetylene 1f, proceeded immedi-
ately to produce 2e and 2f, respectively, in moderate
yields (entries 10 and 11). The hydrosilylation of alkynes
bearing silyloxy and benzyloxy groups gave the corre-
sponding trans-hydrosilylation products in good to high
yields (entries 12-14). Here again, no regio- and stere-
oisomers were detected. Very interestingly, the use of 1.2
equiv of Lewis acids was essential for obtaining good
chemical yields (entries 12-14). Most probably, 1.0 equiv
of the Lewis acids would be needed to coordinate to an
oxygen atom of a silyloxy or benzyloxy group, and the
remaining 0.2 equiv of Lewis acid would act as a catalyst.
The reactions of symmetrical internal acetylenes, such
as 6-dodecyne 1j and tolan 1k , also proceeded smoothly
entries 15 and 16), whereas the reaction of unsym-
metrical acetylenes, such as 1-phenyl-1-propyne 1l and
-phenyl-1-butyne 1m , afforded a mixture of regioiso-
mers, 2l and 3l, and 2m and 3m , respectively (entries
7 and 18). The regioisomeric ratio depended on steric
bulk of the substituent R . The methyl substituent gave
a ratio of 76:10, whereas the ethyl group afforded that
of 54:26.
6
7
8
9
0
1
2
3
4
5
6
7
8
CH3(CH2)9
PhCH2
t-C4H9
1a 90
1b 85
1c 82
Me3Si
1d
0
1
1
1
1
1
1
1
1
1
1e 75
1f 77
1g 86
1h 74
1i 72
d
i-Pr3SiO(CH2)4
CH3(CH2)4
CH3(CH2)4 1j 73
Ph
CH3
C2H5
Ph
Ph
Ph
1k 66
1l 76
1m 54
a
Reactions were conducted in toluene at 0 °C under Ar unless
b
otherwise noted. The starting material 1a was recovered quan-
titatively. c Reaction was carried out without any solvents. d Hex-
ane was used as a solvent.
which the trans-hydrostannation proceeded very smoothly
in the presence of ZrCl
9
4
or HfCl
4
. Fortunately, however,
the reaction in the presence of 0.2 equiv of AlCl
the trans-hydrosilylation product 2a in 93% yield (entry
). Neither a stereoisomer of 2a (cis-addition product) nor
3
afforded
(
3
1
1
a regioisomer (3a ) was detected in the H NMR spectra
of the crude reaction pruduct. While EtAlCl was also
an efficient catalyst for the trans-hydrosilylation (entry
), the starting material 1a was recovered quantitatively
in the Et AlCl-catalyzed reaction (entry 5). It seems that
the reaction did not proceed due to lower Lewis acidity
of Et AlCl, compared to AlCl and EtAlCl . The use of
2
1
2
4
2
3 2
Next, we carried out the AlCl - or EtAlCl -catalyzed
2
3
2
hydrosilylation of 1a with various silanes, and the results
are shown in Table 2. The reaction of tert-butyldimeth-
ylsilane and cyclohexyldimethylsilane proceeded smoothly
to give the corresponding trans-hydrosilylation products
nonpolar solvents such as toluene or hexane was es-
sential for obtaining high stereoselectivity and chemical
yield. Unlike EtAlCl
solvents, and thus the AlCl
proceeded in a heterogeneous system. The AlCl
2
, AlCl
3
is not soluble in such
-catalyzed hydrosilylation
-cata-
3
2
n and 2o, respectively, in good yields (entries 1 and 2).
3
The addition of phenyl-substituted silanes, such as
triphenyl-, diphenylmethyl-, and phenyldimethylsilane,
gave lower yields in comparison with that of alkyl-
substituted silanes (entries 3-5 vs 1 and 2). The reaction
of triethoxysilane did not proceed at all (entry 6). These
results suggest that the silanes having an electron-
donating substituent, such as alkyl groups, are more
suitable to the Lewis acid-catalyzed hydrosilylation.
The Lewis acid-catalyzed hydrosilylation of diyne
compounds was examined. Very interestingly, the AlCl
0.2 equiv)-catalyzed hydrosilylation of 1,6-heptadiyne 4a
with 4 equiv of triethylsilane gave the six-membered
cyclization product 5 in 60% yield, whereas that of 1,7-
lyzed hydrosilylation of 1a proceeded smoothly even
without any solvents to give 2a in 90% yield (entry 6).
The AlCl
examined with several other alkynes. The reactions of
-phenyl-1-propyne 1b and 3,3-dimethyl-1-butyne 1c
3 2
- or EtAlCl -catalyzed hydrosilylation was
3
having a bulky tert-butyl group proceeded smoothly to
produce 2b and 2c, respectively, in high yields (entries
7
and 8), whereas the hydrosilylation of (trimethylsilyl-
)ethyne 1d gave 3d in 89% yield (entry 9). The regio-
3
(
(9) (a) Asao, N.; Liu, J .-X.; Sudoh, T.; Yamamoto, Y. J . Chem. Soc.,
Chem. Commun. 1995, 2405. (b) Asao, N.; Liu, J .-X.; Sudoh, T.;
Yamamoto, Y. J . Org. Chem. 1996, 61, 4568.

2
496 J . Org. Chem., Vol. 64, No. 7, 1999
Sudo et al.
octadiyne 4b afforded bis-hydrosilylation product 6 in
7% yield. The assignment of the stereochemistry of 5
Sch em e 1
4
was made by NOE experiments (see Experimental Sec-
tion). No cyclization product was obtained from 4b under
various reaction conditions: for example, the use of less
than 4 equiv of triethylsilane gave a mixture of 6 and a
mono-hydrosilylation product. The results are in marked
contrast to the cyclization reaction of diyne compounds
1
(entry 1). No regioisomers of 12a were detected by H
1
0
either by Ni-catalyzed- or Rh-catalyzed hydrosilyla-
NMR and GC-MS analysis of the crude reaction mix-
ture. The reaction of p-tolylallene 11b gave 12b in 78%
tion.11
15
Mech a n ism . A plausible mechanism for the AlCl
EtAlCl -catalyzed trans-hydrosilylation is shown in
Scheme 1. As we previously proposed for the Lewis acid-
3
- or
yield (entry 2), and the addition to p-fluorophenylallene
11c afforded 12c in 96% yield (entry 3). The latter result
(entry 3) is in marked contrast with the case of B(C F ) -
2
6
5 3
1
2
13
12
catalyzed hydro- and allylstannation of alkynes, and
catalyzed hydrostannation of 11c, in which only a trace
amount of the hydrostannation product was obtained:
the reason for this difference is not clear. On the other
hand, the allene 11d , bearing a strong electron-with-
drawing trifluoromethyl group at the para-position of
phenyl ring, underwent no hydrosilylation reaction. The
reactions of the allenes 11a -c with triethylsilane gave
the corresponding hydrosilylation products in signifi-
cantly lower yields, compared with those using ethyldim-
ethylsilane. A sterically less demanding trialkylsilane is
more suitable for the hydrosilylation of allenes. Actually,
the hydrosilylation of 1,3-disubstituted allenes (11e-g)
hardly proceeded even with ethyldimethylsilane, and
therefore trimethylsilane was used in those cases (entries
5-9). The addition of trimethylsilane to the allenes
11e-g occurred not only regio- but also stereoselectively
to give the corresponding adducts (12e-g) in good to fair
yields (entries 5-7). Very interestingly, in the case of 11e,
allylsilylation of alkynes,14 AlCl
or EtAlCl (AlX ) would
3
2
3
coordinate to the acetylenic bond of 1 to produce the
zwitterionic intermediate 7 through a π-complex. A
hydride from HSiR
carbon from the side opposite to AlX
3
would attack an electron deficient
to produce an
3
aluminum ate-complex 8. The intermediate 8 would
undergo coupling between trialkylsilyl cation and a vinyl
group with retention of geometry to give 2 and AlX . This
3
mechanism can explain the reverse regioselectivity in the
hydrosilylation of (trimethylsilyl)acetylene 1d mentioned
3
above (Table 1, entry 9). The coordination of AlX to 1d
would afford the zwitterionic intermediate 9a , instead
of another regioisomer 9b, since the trialkylsilyl group
stabilizes a â-cationic carbon significantly and destabi-
lizes an R-cationic carbon.1 Subsequent reaction of 9a
with triethylsilane via a similar transformation pathway
as shown in Scheme 1 would produce 3d through 10.
c
1
1f, and 11g, the E-vinylsilanes (12e-g) were obtained
stereoselectively (entries 5-7), and no stereoisomers were
detected by the H NMR and GC-MS analysis of the crude
1
reaction mixture. Furthermore, even the trisubstituted
allene 11h underwent regioselective hydrosilylation with
trimethylsilane to give the tetrasubstituted vinylsilane
1
2h in 58% yield (entry 8). It should be noted that the
tetrasubstituted vinylsilane 12h cannot be obtained
through the hydrosilylation of alkynes. 1,1-Disubstituted
allene 11i also reacted with trimethylsilane to give the
vinylsilane 12i in 46% yield (entry 9). All the allenes
examined in Table 3 possess an aromatic substituent (see
Allen es. The hydrosilylation of substituted allenes 11
was catalyzed dramatically by AlCl
sponding vinylsilanes 12 regio- and stereoselectively (eq
). The results are summarized in Table 3. The AlCl
3
to give the corre-
11), and a hydride from HSiR always attacks the carbon
3
3
3
-
attached to the aromatic ring. We also examined allenes
catalyzed (0.2 equiv) reaction of phenylallene 11a (1
equiv) with dimethylethylsilane (2 equiv) gave the hy-
drosilylation product 12a regioselectively in 76% yield
substituted only with aliphatic groups. However, the
hydrosilylation did not proceed at all with those aliphatic
allenes.
Mech a n ism . The following mechanistic rationale can
explain the regio- and stereoselective hydrosilylation of
allenes (Scheme 2). AlCl would coordinate to the double
3
(
10) Tamao, K.; Kobayashi, K.; Ito, Y. J . Am. Chem. Soc. 1989, 111,
6
1
6
487.
(
998, 120, 6690.
11) Ojima, I.; Zhu, J .; Vidal, E. S.; Kass, D. F. J . Am. Chem. Soc.
(
12) Gevorgyan, V.; Liu, J .-X.; Yamamoto, Y. J . Org. Chem. 1997,
2, 2963.
13) Asao, N.; Matsukawa, Y.; Yamamoto, Y. J . Chem. Soc., Chem.
Commun. 1996, 1513.
14) (a) Asao, N.; Yoshikawa, E.; Yamamoto, Y. J . Org. Chem. 1996,
1, 4874. (b) Yoshikawa, E.; Gevorgyan, V.; Asao, N.; Yamamoto, Y.
J . Am. Chem. Soc. 1997, 119, 6781.
(15) Possible regioisomers are shown below. These isomers were not
detected.
(
(
6

Trans-Hydrosilylation of Alkynes and Allenes
J . Org. Chem., Vol. 64, No. 7, 1999 2497
Ta ble 3. Lew is Acid -Ca ta lyzed Hyd r osilyla tion of Allen es w ith HSiR3
1
1
entry
R1
R2
R3
Ar
HSiR3
product
yield (%)a,b
1
2
3
H
H
H
H
Me
Me
Me
Me
H
H
H
H
H
H
H
H
Me
H
H
H
H
H
H
H
H
H
C6H5
11a
11b
11c
11d
11e
11f
11g
11h
11i
HSiMe2Et
HSiMe2Et
HSiMe2Et
HSiMe2Et
HSiMe3
HSiMe3
HSiMe3
HSiMe3
HSiMe3
12a
12b
12c
-
12e
12f
12g
12h
12i
76
78
96
0
60
66
72
58
46
p-Me-C6H4
p-F-C6H4
p-CF3-C6H4
p-Me-C6H4
C6H5
p-F-C6H4
p-F-C6H4
p-F-C6H4
c
4
5
6
7
8
9
Me
a
The reactions were carried out in the Wheaton microreactors with 0.5 mmol of 11 and 1.0 mmol of HSiR3 in CH2Cl2 (0.5 mL) at 0 °C
b
c
in the presence of AlCl3 (0.1 mmol). Isolated yield. The starting material 11d was recovered.
Sch em e 2
Sch em e 3
3
congestion between methyl group at C-3 and AlCl . The
selective formation of the trans-vinylaluminate 14E
would give vinylsilanes 12e-g stereoselectively.
In summary, we have succeeded in achieving the Lewis
acid-catalyzed trans-hydrosilylation of alkynes and al-
lenes with trialkylsilanes under mild conditions. Since
this reaction proceeds in a highly regio- and stereocon-
trolled manner, we are now in a position to prepare a
various type of vinylsilanes which are not easily available
via the previously known methodologies.1
bond of an allene to produce the zwitterionic intermediate
4 through π-complex 13. Hydride transfer from HSiR
to 14 would give the ate-complex 15, which would
1
3
undergo facile transmetalation to afford the vinylsilane
1
2 and AlCl
3
6,17
. Aromatic groups such as p-CH
3
-C
stabilize significantly the benzyl cation of
-C destabilizes the carbocation due
to the strong electron-withdrawing effect of CF -group.
6 4
H and
1
6 4
p-F-C H
1
4, whereas p-CF
3
6 4
H
Exp er im en ta l Section
3
Accordingly, the reaction did not proceed at all in the case
of 11d . Probably, in the case of allenes substituted only
with aliphatic groups, the stabilization of the carbocation
Gen er a l In for m a tion . All solvents were purified and dried
before use according to the standard procedures. Reactions
were performed under an argon atmosphere in oven-dried
glassware. Trialkylsilanes, with exception of trimethylsilane,
and the following alkynes were commercially available and
dried whenever necessary: 1a , 1b, 1c, 1d , 1e, 1f, 1j, 1k , 1l,
3
derived from AlCl coordination would be weak in com-
parison with that derived from aromatic allenes, and
therefore the hydrosilylation did not occur with aliphatic
allenes. The above mechanism also explains very nicely
the regiochemistry of the hydrosilylation; Si always
attaches at the central carbon of allenes, and hydride
attaches at the carbon bearing the aromatic group. In
the reaction of the 1,3-disubstituted allenes (11e-g), the
trans-vinylsilanes (12e-g) were obtained stereoselec-
tively, and this stereoselectivity can be explained by the
1
m , 4a , 4b. Trimethylsilane was prepared according to the
1
8
literature procedure. The alkynes bearing silyloxy and ben-
zyloxy groups were prepared according to the standard pro-
cedure from the corresponding alkynols. The substituted
19
allenes 11 were prepared according to the literature proce-
dure.20
(Z)-1-(Tr ieth ylsilyl)-1-d od ecen e (2a ). Preparation of 2a
from 1a is representative. To a suspension of AlCl
3
(27 mg,
0
.2 mmol) in toluene (1.0 mL) was added triethylsilane (0.19
3
geometry of allene double bond (Scheme 3). AlCl would
coordinate to the double bond of the allenes (11e-g) as
shown in Scheme 3 in order to diminish the steric
(
18) Gevorgyan, V. N.; Ignatovich, L. M.; Lukevics, E. J . Organomet.
Chem. 1985, 284, C31-32.
19) Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic
(
(
16) Chambers, R. D. In Fluorine in Organic Chemistry; Wiley: New
York, 1973; pp 73-75.
17) (a) Brown, H. C.; Okamoto, Y. J . Am. Chem. Soc. 1957, 79, 1913.
b) Brown, H. C.; Okamoto, Y. J . Am. Chem. Soc. 1958, 80, 4979. (c)
Brown, H. C.; Okamoto, Y. J . Org. Chem. 1957, 22, 485.
Synthesis; J ohn Wiley: New York, 1991.
(20) Brandsma, L.; Verkruijsse, H. D. Synthesis of Acetylenes, Allenes
and Cumulenes; Elsevier: New York, 1981.
(21) J un, C.-H.; Crabtree, R, C. J . Organomet. Chem. 1993, 447, 177.
The spectral data of 2c and 2f were reported in this paper.
(
(

2
498 J . Org. Chem., Vol. 64, No. 7, 1999
Sudo et al.
mL, 1.2 mmol) at 0 °C under an Ar atmosphere. The mixture
was stirred for 5 min, and then 1a (0.21 mL, 1.0 mmol) was
added. The mixture was stirred for 1 h at 0 °C, and excess
amounts of triethylamine (0.2 mL, 1.5 mmol) were added. After
Hz, 2H), 1.98 (t, J ) 7.2 Hz, 2H), 1.20-1.40 (m, 12H), 0.94 (t,
J ) 7.5 Hz, 9H), 0.89 (t, J ) 7.0 Hz, 3H), 0.88 (t, J ) 7.0 Hz,
3H), 0.64 (q, J ) 7.5 Hz, 6H). 13C NMR (CDCl
67.9 MHz) δ
3
144.0, 136.2, 38.4, 32.1, 31.8, 31.7, 30.8, 29.9, 22.7, 14.1, 14.0,
-
1
addition of aqueous NaHCO
3
solution, the usual workup gave
7.6, 4.3 Hz. IR (neat) 2956, 2873, 1608, 1460, cm . HRMS
+
+
a crude product, which was purified by silica gel column
chromatography using hexane as an eluent to afford 2a (263
mg, 0.93 mmol) in 93% yield. The addition order of reagent,
substrate, and Lewis acid is important to obtain higher yields
of the desired product. The order mentioned in the synthesis
(EI) calcd for 282.2743 (M ), found 282.2750 (M ).
1
(Z)-(Tr ieth ylsilyl)stilben e (2k ): H NMR (CDCl
3
, 270
MHz) δ 7.17-7.33 (m, 11H), 0.80 (t, J ) 8.0 Hz, 9H), 0.41 (q,
J ) 8.1 Hz, 6H). 13C NMR (CDCl3, 67.9 MHz) δ 147.6, 146.3,
145.2, 140.6, 128.3, 127.9, 127.8, 127.4, 127.2, 125.6, 7.5, 4.7
-
1
of 2a is essential. If the acetylene 1a was added to AlCl
to the addition of Et SiH, significant amounts of the trimer-
ization product of 1a (aromatic compounds) were obtained as
a byproduct. Accordingly, it seems that coexistence of Et SiH
is needed, when the coordination of AlCl to the acetylene takes
place, to instantaneously capture an activated triple bond. H
NMR (CDCl , 270 MHz) δ 6.37 (dt, J ) 7.3, 14.3 Hz, 1H),
.38 (d, J ) 14.3 Hz, 1H), 2.09 (dt, J ) 7.3, 7.3 Hz, 2H), 1.27
bs, 16H), 0.95 (t, J ) 7.7 Hz, 9H), 0.90 (t, J ) 6.6 Hz, 3H),
3
prior
Hz. IR (neat) 2954, 2872, 1597, 1493, 1464 cm . HRMS (EI)
+
+
3
calcd for 294.1804 (M ), found 294.1807 (M ).
(Z)-1-P h en yl-2-(tr ieth ylsilyl)-1-p r op en e (2l): 1H NMR
3
(CDCl
3H), 0.83 (t, J ) 8.1 Hz, 9H), 0.43 (q, J ) 8.0 Hz, 6H).
NMR (CDCl3, 67.9 MHz) δ 142.7, 140.7, 137.7, 128.4, 127.6,
3
, 270 MHz) δ 7.17-7.25 (m, 6H), 1.95 (d, J ) 1.8 Hz,
13
3
C
1
-1
3
126.6, 26.0, 7.5, 3.9 Hz. IR (neat) 2955, 2870, 1490, 1460 cm .
+
+
5
HRMS (EI) calcd for 232.1647 (M ), found 232.1662 (M ).
1
(
0
1
(Z)-1-P h en yl-1-(tr ieth ylsilyl)-1-p r op en e (3l): H NMR
(CDCl , 400 MHz) δ 6.98-7.28 (m, 5H), 6.22 (q, J ) 7.0 Hz,
.61 (q, J ) 8.0 Hz, 6H). 13C NMR (CDCl
25.0, 34.1, 31.9, 29.8, 29.6, 29.5, 29.4, 22.7, 14.1, 7.5, 4.8 Hz.
, 67.9 MHz) δ 150.4,
3
3
1H), 1.91 (d, J ) 7.0 Hz, 3H,), 0.92 (t, J ) 8.0 Hz, 9H), 0.67 (q,
-
1
13
IR (neat) 2954, 2874, 1605, 1466 cm . HRMS (EI) calcd for
J ) 8.0 Hz, 6H). C NMR (CDCl3, 67.9 MHz) δ 147.8, 147.7,
+
+
2
82.2743 (M ), found 282.2722 (M ).
Z)-3-P h en yl-1-(tr ieth ylsilyl)-1-p r op en e (2b): H NMR
CDCl , 270 MHz) δ 7.17-7.32 (m, 5H), 6.50 (dt, J ) 7.3, 14.3
Hz, 1H), 5.56 (dt, J ) 1.5, 14.3 Hz, 1H), 3.47 (d, J ) 7.3 Hz,
H), 0.98 (t, J ) 7.3 Hz, 9H), 0.69 (q, J ) 7.0 Hz, 6H). 13
NMR (CDCl , 67.9 MHz) δ 147.8, 140.5, 128.4, 126.6, 126.0,
0.0, 27.8, 7.5, 4.8 Hz. IR (neat) 2953, 2873, 1601, 1495, 1454
141.6, 127.6, 127.5, 125.1, 18.0, 7.4, 4.5 Hz. IR (neat) 2952,
1
-1
(
2873, 1595, 1488 cm .
(
3
(Z)-1-P h en yl-2-(tr ieth ylsilyl)-1-bu ten e (2m ): 1H NMR
(CDCl , 270 MHz) δ 7.15-7.26 (m, 6H), 2.23 (dq, J ) 1.5, 7.3
Hz, 2H), 1.10 (t, J ) 7.3 Hz, 3H), 0.82 (t, J ) 8.1 Hz, 9H), 0.43
3
2
C
-
1
3
(q, J ) 8.0 Hz, 6H). IR (neat) 2956, 2873, 1490, 1458 cm .
4
Anal. Calcd for C16
H, 10.12.
H26Si: C, 77.97; H, 10.63. Found: C, 77.93;
-
1
+
2 5
cm . HRMS (EI) calcd for 203.1256 (M - C H ), found
+
(Z)-1-P h en yl-1-(tr ieth ylsilyl)-1-bu ten e (3m ): 1H NMR
2
03.1244 (M - C
Z)-3, 3-Dim eth yl-1-(tr ieth ylsilyl)-1-bu ten e (2c): 1H
NMR (CDCl , 270 MHz) δ 6.45 (d, J ) 16.0 Hz, 1H), 5.20 (d,
J ) 16.0 Hz, 1H), 1.05 (s, 1H), 0.95 (t, J ) 7.0 Hz, 9H), 0.65
2
H
5
).
2
1
(
(CDCl
3
, 270 MHz) δ 6.99-7.25 (m, 5H), 6.09 (t, J ) 7.3 Hz,
3
1H), 2.26 (dq, J ) 7.3, 7.7 Hz, 2H), 1.05 (t, J ) 7.7 Hz, 3H),
1
3
0.90 (t, J ) 7.7 Hz, 9H), 0.64 (q, J ) 7.7 Hz, 6H). C NMR
(CDCl , 67.9 MHz) δ 149.2, 147.7, 139.8, 127.6, 127.5, 125.1,
123.1, 25.6, 14.3, 7.5, 4.7 Hz. IR (neat) 2955, 2873, 1599, 1489
(q, J ) 7.5 Hz, 6H).
3
1
1
-(Tr ieth ylsilyl)-1-(tr im eth ylsilyl)eth en e (2d ): H NMR
-1
+
+
(
CDCl
3
, 270 MHz) δ 6.39 (d, J ) 5.1 Hz, 1H), 6.28 (d, J ) 5.1
cm . HRMS (EI) calcd for 246.1804 (M ), found 246.1801 (M ).
1
Hz, 1H), 0.91 (t, J ) 8.0 Hz, 9H), 0.64 (q, J ) 7.0 Hz, 6H),
0
3
(Z)-1-(ter t-Bu tyldim eth ylsilyl)-1-dodecen e (2n ): H NMR
1
3
.09 (s, 9H). C NMR (CDCl
.7, -0.2 Hz. IR (neat) 2955, 2875, 1460 cm . HRMS (EI) calcd
3
, 67.9 MHz) δ 151.1, 141.6, 7.4,
3
(CDCl , 270 MHz) δ 6.37 (dt, J ) 7.3, 14.3 Hz, 1H), 5.46 (dt,
-1
J ) 1.1, 14.3 Hz, 1H), 2.09 (dt, J ) 7.3, 7.3 Hz, 2H), 1.27 (bs,
+
+
13
for 214.1573 (M ), found 214.1579 (M ).
Z)-1-(Tr ieth ylsilyl)-3-cycloh exen yleth en e (2e): 1H NMR
CDCl , 270 MHz) δ 6.74 (dd, J ) 1.1, 15.0 Hz, 1H), 5.65 (bs,
H), 5.32 (d, J ) 15.0 Hz, 1H), 2.00-2.10 (m, 4H), 1.55-1.67
m, 4H), 0.93 (t, J ) 8.1 Hz, 9H), 0.60 (q, J ) 8.1 Hz. 6H). 13
NMR (CDCl3, 67.9 MHz) δ 150.8, 138.8, 125.7, 124.7, 27.8, 25.5,
16H), 0.88 (bs, 12H) C NMR (CDCl3, 67.9 MHz) δ 150.3,
(
125.7, 33.7, 31.9, 29.8, 29.6, 29.4, 29.3, 26.4, 22.7, 16.8, 14.1,
-1
(
1
(
3
1.9, -4.1 Hz. IR (neat) 2955, 2926, 1607, 1464 cm HRMS(EI)
+
+
calcd for 282.2743 (M ), found 282.2720 (M ).
C
(Z)-1-(Cycloh exyld im eth ylsilyl)-1-d od ecen e (2o): 1H
NMR (CDCl , 270 MHz) δ 6.34 (dt, J ) 7.3, 13.9 Hz, 1H), 5.42
3
-
1
2
2.7, 22.2, 7.6, 5.2 Hz. IR (neat) 2951, 2874, 1589, 1458 cm
.
(dt, J ) 1.3, 13.9 Hz, 1H), 2.09 (dt, J ) 7.0, 7.0 Hz, 2H), 1.65-
+
+
HRMS (EI) calcd for 222.1804 (M ), found 222.1811 (M ).
1.75 (m, 6H), 1.00-1.40 (m, 20H), 0.89 (t, J ) 7.0 Hz, 3H),
2
1
1
13
(
Z)-â-Tr ieth ylsilylstyr en e (2f):
H NMR (CDCl
3
, 270
3
0.64 (tt, J ) 2.8, 12.0 Hz, 1H), 0.05 (s, 6H). C NMR (CDCl ,
MHz) δ 7.55 (d, J ) 15.0 Hz, 1H), 7.25-7.28 (m, 5H), 5.76 (d,
67.9 MHz) δ 149.9, 126.8, 126.7, 33.9, 32.0, 29.8, 29.7, 29.4,
28.2, 27.5, 27.1, 26.5, 24.2, 22.7, 14.1, -3.4 Hz. IR (neat) 2957,
J ) 15.0 Hz, 1H), 0.87 (t, J ) 8.0 Hz, 9H), 0.56 (q, J ) 7.0 Hz,
-
1
+
6
H).
2853, 1607, 1466 cm . HRMS (EI) calcd for 308.2899 (M ),
+
(
Z)-4-(Tr iisop r op ylsiloxy)-1-(t r ie t h ylsilyl)-1-b u t e n e
found 308.2892 (M ).
1
(Z)-1-(Tr ip h en ysilyl)-1-d od ecen e (2p ): 1H NMR (CDCl
(
1
(
9
2g): H NMR (CDCl
H), 5.50 (d, J ) 14.3 Hz, 1H), 3.73 (t, J ) 7.0 Hz, 2H), 2.37
dt, J ) 7.0, 7.0 Hz, 2H), 1.07 (bs, 21H), 0.95 (t, J ) 7.7 Hz,
3
, 270 MHz) δ 6.43 (dt, J ) 7.3, 14.3 Hz,
3
,
270 MHz) δ 7.55-7.59 (m, 6H), 7.64-7.41 (m, 9H), 6.70 (dt, J
) 7.3, 14.3 Hz, 1H), 6.02 (d, J ) 14.3 Hz, 1H), 1.90 (dt, J )
7.3, 7.3 Hz, 2H), 0.94-1.30 (m, 16H), 0.88 (t, J ) 8.6 Hz, 3H).
H), 0.62 (q, J ) 6.9 Hz, 6H). IR (neat) 2954, 2868, 1607, 1464
-
1
-1
cm . Anal. Calcd for C19
C, 66.85; H, 12.62.
H
42OSi
2
: C, 66.58; H, 12.35. Found:
IR (neat) 2954, 2853, 1603, 1485 cm . Anal. Calcd for
C
30
H
38Si: C, 84.44; H, 8.98. found: C, 84.71; H, 9.25.
(Z)-1-(Meth yld ip h en ylsilyl)-1-d od ecen e (2q): 1H NMR
(CDCl , 270 MHz) δ 7.52-7.57 (m, 4H), 7.29-7.37 (m, 6H),
(
Z)-6-(Tr iisop r op ylsiloxy)-1-(t r iet h ylsilyl)-1-h exen e
1
(
2h ): H NMR (CDCl
3
, 270 MHz) δ 6.38 (dt, J ) 7.0, 14.3 Hz,
3
1
2
2
6
H), 5.40 (dt, J ) 1.4, 14.3 Hz, 1H), 3.69 (t, J ) 6.2 Hz, 2H),
6.57 (dt, J ) 7.3, 13.9 Hz, 1H), 5.80 (d, J ) 13.9 Hz, 1H), 1.93
.14 (ddt, J ) 1.4, 7.7, 7.7 Hz, 2H), 1.41-1.59 (m, 4H). IR (neat)
(dt, J ) 7.3, 7.3 Hz, 2H), 1.09-1.26 (m, 16H), 0.88 (t, J ) 6.6
945, 2868, 1605, 1462 cm-1. Anal. Calcd for C21
8.03; H, 12.51. found: C, 67.75; H, 12.06.
H
46OSi
: C,
Hz, 9H), 0.65 (s, 3H). IR (neat) 2957, 2853, 1603, 1466 cm .
-1
2
Anal. Calcd for C25
H, 9.96.
H36Si: C, 82.34; H, 9.95. Found: C, 82.61;
(
Z)-4-(Ben zyloxy)-2-(tr ieth ylsilyl)-1-bu ten e (2i): 1H NMR
(
CDCl
3
, 270 MHz) δ 7.25-7.33 (m, 5H), 6.39 (dt, J ) 7.3, 14.3
(Z)-1-(Dim eth ylp h en ylsilyl)-1-d od ecen e (2r ): 1H NMR
Hz, 1H), 5.52 (dt, J ) 1.5, 14.3 Hz, 1H), 4.51 (s, 2H), 3.50 (ddt,
J ) 7.0 Hz, 2H), 2.44 (ddt, J ) 1.5, 7.3, 7.3 Hz, 2H), 0.93 (t, J
3
(CDCl , 270 MHz) δ 7.53-7.58 (m, 2H), 7.33-7.37 (m, 3H),
6.44 (dt, J ) 7.3, 13.9 Hz, 1H), 5.62 (dt, J ) 1.5, 13.9 Hz, 1H),
2.04 (dt, J ) 7.7, 7.7 Hz, 2H), 1.21-1.39 (m, 16H), 0.89 (t, J )
1
3
)
3
7.7 Hz, 9H), 0.61 (q, J ) 7.7 Hz, 6H). C NMR (CDCl , 67.9
-1.
MHz) δ 145.6, 138.5, 128.3, 127.7, 127.6, 127.5, 72.9, 69.9, 34.4,
6.2 Hz, 3H), 0.38 (s, 6H). IR (neat) 2957,2855, 1605, 1466 cm
-1
7
.5, 4.6 Hz. IR (neat) 2952, 2874, 1607, 1454 cm . HRMS (EI)
Anal. Calcd for C20
H, 11.48.
H34Si: C, 79.31; H, 11.32. found: C, 79.64;
+
+
calcd for 247.1518 (M - C
2
H
5
), found 247.1521 (M - C
2
H
5
)
1
(E)-1-(Tr iet h ylsilyl)-3-m et h ylen ecycloh exen e (5): 1H
(
Z)-6-(Tr ieth ylsilyl)-6-d od ecen e (2j): H NMR (CDCl3,
2
70 MHz) δ 5.98 (tt, J ) 1.0, 7.2 Hz, 1H), 2.07 (dt, J ) 7.0, 7.0
3
NMR (CDCl , 270 MHz) _ 6.11 (ddt, J ) 0.7, 1.3, 9.6 Hz, 1H),

Trans-Hydrosilylation of Alkynes and Allenes
J . Org. Chem., Vol. 64, No. 7, 1999 2499
1
2
2
30.5, 126.5, 114.8, 42.1, 7.24, 6.72, -3.86; IR (neat) 3047,
-
1
835, 1607, 1508, 1437 cm ; HRMS (EI) calcd for C13H19FSi
+
+
22.1240 (M ), found 204.1353 (M ).
(
E )-2-(Tr im e t h ylsilyl)-1-(4-m e t h ylp h e n yl)-2-b u t e n e
1
(
(
)
12e): H NMR (CDCl
tq, J ) 5.4, 1.2 Hz, 1H), 3.51 (s, 2H), 2.31 (s, 2H), 1.76 (d, J
5.4 Hz, 3H), -0.06 (s, 9H); 13C NMR (CDCl
, 67.8 MHz) δ
140.3, 137.6, 135.5, 134.9, 128.8, 128.3, 34.2, 21.0, 14.7, -1.26;
IR (neat) 3047, 2870, 1616, 1510, 1454 cm ; HRMS (EI) calcd
for C14
3
, 270 MHz) δ 7.03-7.08 (m, 4H), 6.09
3
F igu r e 1. NOE experiments of 5.
-1
5
.81 (dt, J ) 4.4, 9.5 Hz, 1H), 5.20 (bs, 1H), 2.40 (m, 2H), 2.12
+
+
H22Si 218.1491 (M ), found 218.1477 (M ).
(m, 2H), 1.72 (tt, J ) 6.1, 6.3 Hz, 2H), 0.94 (q, J ) 7.6 Hz,
E)-2-(Tr im eth ylsilyl)-1-p h en yl-2-bu ten e (12f): 1H NMR
(
6
1
H), 0.62 (t, J ) 8.4 Hz, 9H). IR (neat) 2912, 2831, 1692, 1576,
1
(
CDCl , 270 MHz) δ 7.20-7.34 (m, 5H), 6.18 (tq, J ) 5.4, 1.2
Hz, 1H), 3.62 (s, 2H), 1.84 (d, J ) 5.4 Hz, 3H), 0.00 (s, 9H);
13
3
-
458 cm . Anal. Calcd for C13H24Si: C, 74.91; H, 11.61.
Found: C, 74.81; H, 11.96. NOE experiments were performed
by irradiation of signals at 5.20 and 6.11 ppm. Signals showing
NOE were indicated in Figure 1.
C NMR (CDCl , 67.8 MHz) δ 142.5, 140.9, 140.2, 135.7, 128.5,
3
1
1
2
28.1, 34.7, 14.8, -1.30; IR (neat) 3084, 2853, 1614, 1495, 1452,
-1
+
248 cm ; HRMS (EI) calcd for C13
H
20Si 204.1333 (M ), found
2
-(Dim et h ylet h ylsilyl)-3-(4-m et h ylp h en yl)-1-p r op en e
12a ). Preparation of 12a from 11a is representative. To a
suspension of AlCl (13 mg, 0.1 mmol) in CH Cl (0.5 mL) was
+
04.1371 (M ).
(
(
E )-2-(Tr im e t h ylsilyl)-1-(4-flu or op h e n yl)-2-b u t e n e
3
2
2
1
(
12g): H NMR (CDCl
3
, 270 MHz) δ m, 4H), 6.11 (tq, J ) 5.4,
.2 Hz, 1H), 3.52 (s, 2H), 1.76 (d, J ) 5.4 Hz, 3H), -0.06 (s,
H); 13C NMR (CDCl
, 67.8 Hz) δ 160.8, 139.4, 136.0, 129.4,
29.3, 114.8, 114.2, 33.4, 14.3, -1.69; IR (neat) 3055, 2876,
added dimethyethylsilane (0.14 mL, 1.0 mmol) at 0 °C under
Ar atmosphere. Very slow dropwise addition of allene 11a (0.08
mL, 0.5 mmol) was carried out, and then the mixture was
stirred for 1 h at room temperature. The reaction was
monitored by GC-MS. Aqueous NaHCO solution was added
3
slowly at 0 °C, and then the usual workup gave crude product,
which was purified by silica gel column chromatography using
1
9
1
1
3
-
1
605, 1508 cm ; HRMS (EI) calcd for C13H19FSi 222.1239
+
+
(
M ), found 222.1233 (M ).
1
-(4-F lu o r o p h e n y l)-2-(t r im e t h y ls ily l)-3-m e t h y l-2-
1
bu ten e (12h ): H NMR (CDCl
4H), 3.48 (s, 2H), 1.96 (s, 3H), 1.75 (s, 3H), 0.56 (s, 9H);
NMR (CDCl , 67.8 MHz) δ 161.1, 145.5, 136.9, 130.3, 129.3,
14.7, 36.7, 25.4, 21.4, 0.63; IR (neat) 3067, 2862, 1601, 1506,
1448 cm ; HRMS (EI) calcd for C H FSi 236.1395 (M ),
found 236.1390 (M ).
3
, 270 MHz) δ 6.92-7.06 (m,
hexane as an eluent to afford 12a (83 mg, 0.38 mmol) in 76%
13
1
C
yield. H NMR (CDCl
(
2
2
3
, 270 MHz) δ 7.02-7.10 (m, 4H), 5.48
dt, J ) 3.0, 1.5 Hz, 1H), 5.41 (dt, J ) 3.0, 1.5 Hz, 1H), 3.41 (s,
3
1
H), 2.32 (s, 3H), 0.87 (t, J ) 8.1 Hz, 3H), 0.42 (q, J ) 7.8 Hz,
-
1
+
-1
H), -0.03 (s, 6H); IR (neat) 3091, 2874, 1514, 1460 cm . Anal.
14 21
+
Calcd for C14
.94.
H22Si: C, 76.99; H, 10.15. Found: C, 76.76; H,
1
9
2-(Tr im eth ylsilyl)-3-(4-flu or op h en yl)-1-bu ten e (12i): H
2
-(Dim eth yleth ylsilyl)-3-p h en yl-1-p r op en e (12b): 1H
NMR (CDCl , 270 MHz) δ 7.14-7.30 (m, 5H), 5.49 (dt, J )
.0, 1.5 Hz, 1H), 5.42 (dt, J ) 3.0, 1.5 Hz, 1H), 3.45 (s, 2H),
.86 (t, J ) 7.8 Hz, 3H), 0.46 (q, J ) 7.8 Hz, 2H), -0.03 (s,
3
NMR (CDCl , 270 MHz) δ 6.93-7.26 (m, 4H), 5.70 (dd, J )
3
2.1, 0.9 Hz, 1H), 5.11 (dd, J ) 2.1, 0.9 Hz, 1H) 3.64 (q, J ) 6.9
Hz, 1H), 1.35 (d, J ) 6.9 Hz, 3H), -0.07 (s, 9H); IR (neat) 3053,
3
0
6
1
-
1
2876, 1605, 1508, 1458, 1222 cm ; HRMS (EI) calcd for
1
3
+
+
H); C NMR (CDCl
3
, 67.8 MHz) δ 150.4, 149.1, 129.3, 128.1,
C
13
H
19FSi 222.1239 (M ), found 222.1195 (M ).
26.3, 125.9, 42.9, 7.28, 0.72, -3.84; IR (neat) 3084, 2835, 1495
cm ; HRMS (EI) calcd for C13H20Si 204.1334 (M ), found
04.1353 (M ).
-(Dim et h ylet h ylsilyl)-3-(4-flu or op h en yl)-1-p r op en e
-
1
+
Su p p or tin g In for m a tion Ava ila ble: Full details of the
+
2
1
13
2
2
1
70 MHz H NMR and C NMR spectra of 2a , 2b, 2c, 2d , 2e,
f, 2g, 2h , 2i, 2j, 2k , 2l, 3l, 2m , 3m , 2n , 2o, 2p , 2q, 2r , 5, 6,
2a , 12b, 12c, 12e, 12f, 12g, 12h , and 12i. This material is
2
1
(
(
12c): H NMR (CDCl
dt, J ) 3.0, 1.5 Hz, 1H), 5.42 (dt, J ) 3.0, 1.5 Hz, 1H), 3.42 (s,
H), 0.86 (t, J ) 7.8 Hz, 3H), 0.45 (q, J ) 7.8 Hz, 2H), -0.04
3
, 270 MHz) δ 6.93-7.12 (m, 4H), 5.48
available free of charge via the Internet at http://pubs.acs.org.
2
(
1
3
3
s, 6H); C NMR (CDCl , 67.8 MHz) δ 161.4, 130.7, 130.6,
J O9824293