Platinum complex-catalyzed hydrosilylation and isomerization of methylenecyclopropane derivatives. Effect of structures of the substrate and catalyst

Article abstract of DOI:10.1021/jo020293+

PtI₂(PPh₃)₂ catalyzes hydrosilylation of 2,2-diphenyl-1-methylenecyclopropane with HSiEt₃, HSiPh₃, HSiEt₂Ph, HSiPhCl₂, and HSiCl₃ under solvent-free conditions at 140°

Full text of DOI:10.1021/jo020293+

P la tin u m Com p lex-Ca ta lyzed Hyd r osilyla tion a n d Isom er iza tion of
Meth ylen ecyclop r op a n e Der iva tives. Effect of Str u ctu r es of th e
Su bstr a te a n d Ca ta lyst
Masumi Itazaki, Yasushi Nishihara, and Kohtaro Osakada*
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku,
Yokohama 226-8503, J apan
kosakada@res.titech.ac.jp
Received April 25, 2002
PtI2(PPh3)2 catalyzes hydrosilylation of 2,2-diphenyl-1-methylenecyclopropane with HSiEt3, HSiPh3,
HSiEt2Ph, HSiPhCl2, and HSiCl3 under solvent-free conditions at 140 °C to produce the silyl
compounds with a (2,2-diphenylcyclopropyl)methyl substituent in moderate to high yields without
ring-opening of the substrate. PtI2(PPh3)2 is converted by the reaction into PtH(I)(PPh3)2, which
also catalyzes the hydrosilylation of the methylenecyclopropanes. The reaction of 2-phenyl-1-
methylenecyclopropane, 2-methyl-2-phenyl-1-methylenecyclopropane, 2,2-diphenethyl-1-methyl-
enecyclopropane, and alkylidenecyclopropanes with HSiEt3 catalyzed by PtI2(PPh3)2 causes addition
of hydrosilane to the substrate accompanied by ring-opening. 2,2-Diphenyl-1-methylenecyclopropane
undergoes ring-opening isomerization in the presence of HSi(OEt)Me2 and Pt(PEt3)3 catalyst to
give 1,1-diphenyl-1,3-butadiene. The pathways for the hydrosilylation and the isomerization are
discussed.
SCHEME 1
In tr od u ction
Methylenecyclopropanes, which have a highly strained
structure due to a three-membered ring attached to the
CdC double bond, often undergo ring-opening promoted
by transition metal complexes. These reactions have been
utilized in many synthetic organic reactions.1 Scheme 1
depicts the possible reactions of organic molecules
(X-Y) with substituted methylenecyclopropanes pro-
moted by metal complexes. Addition of X-Y to the
methylenecyclopropanes would cause functionalization of
the substrates with and without ring-opening (Scheme
1, paths i and ii).2-10 Simple addition of X-Y to the CdC
* Corresponding author. Phone: +81-45-924-5224. Fax: +81-45-
924-5224.
(1) (a) Brandi, A.; Goti, A. Chem. Rev. 1998, 98, 589-635. (b) Binger,
P.; Bu¨ch, H. M. Top. Curr. Chem. 1987, 135, 77-151. (c) Ohta, T.;
Takaya, H. In Comprehensive Organic Synthesis; Trost, B. M., Ed.;
Pergamon: Oxford, 1991; Vol. 5, p 1185.
(2) R3Si-CN: Chatani, N.; Takeyasu, T.; Hanafusa, T. Tetrahedron
bond catalyzed by metal complexes, giving rise to cyclo-
propane-containing compounds (Scheme 1, path ii),2,3,6,9
was observed as the side reaction of the ring-opening
reactions (Scheme 1, path i). Such formation of function-
alized cyclopropane derivatives would be unique and
important from the viewpoint of both transition metal
catalysis and organic synthesis.11
Lett. 1988, 29, 3979-3982.
(3) R3Sn-H: Lautens, M.; Meyer, C.; Lorenz, A. J . Am. Chem. Soc.
1996, 118, 10676-10677.
(4) R2N-H: (a) Tsukada, N.; Shibuya, A.; Nakamura, I.; Yamamoto,
Y. J . Am. Chem. Soc. 1997, 119, 8123-8124. (b) Nakamura, I.; Itagaki,
H.; Yamamoto, Y. J . Org. Chem. 1998, 63, 6458-6459.
(5) (a) RO-H: Camacho, D. H.; Nakamura, I.; Saito, S.; Yamamoto,
Y. Angew. Chem., Int. Ed. 1999, 38, 3365-3367. (b) Camacho, D. H.;
Nakamura, I.; Saito, S.; Yamamoto, Y. J . Org. Chem. 2001, 66, 270-
275.
(6) R2B-BR2: Ishiyama, T.; Momota, S.; Miyaura, N. Synlett 1999,
1790-1792.
(9) Addition of silyl compounds to bicyclopropylidene without ring-
opening has been achieved recently. See: Pohlmann, T.; de Meijere,
A. Org. Lett. 2000, 2, 3877-3879.
(7) R3Si-BR2: Suginome, M.; Matsuda, T.; Ito, Y. J . Am. Chem. Soc.
2000, 122, 11015-11016.
(8) R3Si-H: (a) Bessmertnykh, A. G.; Blinov, K. A.; Grishin, Yu.
K.; Donskaya, N. A.; Tveritinova, E. V.; Yur‘eva, N. M.; Beletskaya, I.
P. J . Org. Chem. 1997, 62, 6069-6076. (b) Bessmertnykh, A. G.; Blinov,
K. A.; Grishin, Yu. K.; Donskaya, N. A.; Tveritinova, E. V.; Beletskaya,
I. P. Russ. J . Org. Chem. 1969, 34, 799-808.
(10) RS-H, RS-SR: Xu, B.; Chen, Y.; Shi, M. Tetrahedron Lett.
2002, 43, 2781-2784.
(11) For example; (a) de Meijere, A.; Wessjohann, L. Synlett 1990,
20-32. (b) Brandi, A.; Cordero, F. M.; de Sarlo, F.; Goti, A.; Guarna,
A. Synlett 1993, 1-8.
10.1021/jo020293+ CCC: $22.00 © 2002 American Chemical Society
Published on Web 09/07/2002
J . Org. Chem. 2002, 67, 6889-6895
6889

Itazaki et al.
TABLE 1. Hyd r osilyla tion of
2,2-Dip h en yl-1-m eth ylen ecyclop r op a n e w ith
Tr ieth ylsila n ea
TABLE 2. P la tin u m -Ca ta lyzed Hyd r osilyla tion of
Meth ylen ecyclop r op a n es w ith Hyd r osila n esa
product
%
% yieldd of product
1a 2a
87e
methylenecyclopropane
%
entry
catalyst
time/h
3
entry
R1
R2
hydrosilane
1
yieldc
2
yieldc
1b
2b
3b
4b
5
PtI2(PPh3)2
1
1
1
3
6
6
6
3
0
0
0
0
0
0
0
0
0
9
0
1
2
3
4
5
6
7
8
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
HSiPh3
1b 53
85
1d 81
Pt(H)I(PPh3)2
Pt(H)Cl(PPh3)2
PtCl2(PPh3)2
PtI2(cod) + PPh3
PtI2(cod) + PCy3
PtI2(cod) + PtBu3
Pt(PPh3)4
H2PtCl6‚6H2O
H2PtCl6‚6H2O
(Bu4N)2PtCl6
Pt-C (10%)
87e
85e
68e
67
40
23
58
trace
7
HSiEt2Ph
HSiPhCl2
HSiCl3
HSi(OEt)3
HSiMe2(OEt)
1c
1e
81
0
0
6
7
8
9
47
39
6
23
0
17
0
0
C6H4F-4
(CH2)2Ph
C6H4F-4 HSiEt3
(CH2)2Ph HSiEt3
Me
H
1f
80
1g 46 2g 40
1h 27 2h 40
3
48
1
9b Ph
HSiEt3
HSiEt3
HSiEt3
10c
11
12
0
10 Ph
0
0
2i
2j
57
37
6
0
62
0
0
11 C6H4OMe-4
H
48
40e
a
Reactions of disubstituted methylenecyclopropane with hy-
drosilane (1:2) were carried out in the presence of 3 mol % of
PtI2(PPh3)2 without solvent at 80 °C for 4 h (entry 4), for 1 h (entry
5), or at 140 °C for 1 h (other entries). Two diastereomers of 1h
(1:1) and isomeric products 1h and 2h were not separated.
a
Reactions of 2,2-diphenyl-1-methylenecyclopropane with tri-
ethylsilane (1:2) were carried out in the presence of 3 mol % of a
b
Pt catalyst at 140 °C (cod ) 1,5-cyclooctadiene). No solvent was
b
used. c In 2-propanol. The yields were determined by 1H NMR
d
based on diphenylmethane as internal standard, unless otherwise
c Isolated yields.
stated. e Isolated yields.
1a selectively (entries 2 and 3). PtI2(PPh3)2 acts as a
precursor of PtH(I)(PPh3)2, which is the actual catalyst
of the reaction (vide infra). The reactions catalyzed by
PtCl2(PPh3)2 and by a mixture of PtI2(cod) and PPh3 form
1a in lower yields (entries 4 and 5). PtI2(cod) with bulky
trialkylphosphine, PCy3, or PtBu3, leads to a mixture of
1a and (2,2-diphenyl-3-butenyl)triethylsilane (2a ), the
latter of which is formed via hydrosilylation accompanied
by ring-opening (entries 6 and 7). Speier’s catalyst
(H2PtCl6‚6H2O) and (Bu4N)2PtCl6, which are the typical
catalysts for hydrosilylation of alkenes, and heteroge-
neous Pt-C (10%) are not active for the hydrosilylation
of 2,2-diphenyl-1-methylenecyclopropanes or form 2a
more easily than 1a (entries 9-12). Several other transi-
tion metal complexes, such as Pd(PPh3)4, Pd-C(10%), Ni-
(cod)2 (cod ) 1,5-cyclooctadiene), and Ni(PPh3)4, do not
catalyze the hydrosilylation of 2,2-diphenyl-1-methyl-
enecyclopropane.
Table 2 summarizes the results of hydrosilylation of
various methylenecyclopropanes catalyzed by PtI2(PPh3)2.
The reactions of 2,2-diphenyl-1-methylenecyclopropane
with HSiPh3, HSiEt2Ph, HSiPhCl2, and HSiCl3 produce
1b-e in moderate to high yields (entries 1-4) via the
addition of Si-H bond to the CdC double bond without
ring-opening. Alkoxysilanes such as HSi(OEt)3 and
HSiMe2(OEt) provide no silylated product at all under
similar conditions (entries 5 and 6). The reaction of 2,2-
bis(4-fluorophenyl)-1-methylenecyclopropane with HSiEt3
yields the hydrosilylated product 1f predominantly (entry
7). The reactions of 2,2-bis(2-phenylethyl)-1-methylenecy-
clopropane and 2-methyl-2-phenyl-1-methylenecyclopro-
pane with HSiEt3 afford mixtures of 1 and 2 in 46:40 and
27:40 ratios, respectively (entries 8 and 9). 2-Phenyl-1-
There have been only a few reports of hydrosilylation
of methylenecyclopropanes. Rh complexes catalyzed hy-
drosilylation of (diphenylmethylene)cyclopropane with
HSiEt3 was reported to produce (4-triethylsilyl)-1,1-di-
phenyl-1-butene via ring-opening.8 Use of unsymmetri-
cally substituted methylenecyclopropanes in the hydros-
ilylation will render complicated hydrosilylated products,
because the substrates have three different (two proximal
and one distal) bonds that may be cleaved during the
hydrosilylation. We recently found that the stoichiometric
reaction of 2,2-disubstituted methylenecyclopropanes
with a hydridorhodium complex causes the selective
cleavage of the proximal C-C bond triggered by insertion
of CdC double bond into the Rh-H bond.12 It suggests a
possibility of selective hydrosilylation of these sterically
congested methylenecyclopropanes.
In this paper we report the reactions of triorganosi-
lanes with methylenecyclopropanes catalyzed by plati-
num complexes, affording silylated cyclopropanes or 1,3-
dienes selectively, depending on the kind of catalysts and
organosilanes. A part of this work was reported prelimi-
narily.13
Resu lts a n d Discu ssion
P la tin u m Com p lex-Ca ta lyzed Hyd r osilyla tion of
Meth ylen ecyclop r op a n es. Table 1 summarizes the
results of the reaction of 2,2-diphenyl-1-methylenecyclo-
propane with HSiEt3 (1:2) in the presence of various Pt
complexes. Heating of the mixture and PtI2(PPh3)2 cata-
lyst at 140 °C without solvent produces [(2,2-diphenyl-
cyclopropyl)methyl]triethylsilane (1a ) in 87% isolated
yield (entry 1). The reaction in toluene at 110 °C forms
not only 1a (74% by NMR) but also 1,1-diphenyl-1,3-
butadiene (3, 10%)14 after 3 h, while that at 110 °C
without solvent 1a is found exclusively (81% by NMR).
The hydridoplatinum complexes PtH(I)(PPh3)2 and PtH-
(Cl)(PPh3)2 also catalyze the hydrosilylation to produce
(12) Nishihara, Y.; Yoda, C.; Osakada, K. Organometallics 2001, 20,
2124-2126.
(13) Nishihara, Y.; Itazaki, M.; Osakada, K. Tetrahedron Lett. 2002,
43, 2059-2061.
(14) Drexler, J .; Lindermayer, R.; Hassan, M. A.; Sauer, J . Tetra-
hedron Lett. 1985, 26, 2555-2558.
6890 J . Org. Chem., Vol. 67, No. 20, 2002

Catalyzed Reaction of Methylenecyclopropanes
SCHEME 2 a
TABLE 3. P t(P Et3)3-Ca ta lyzed Isom er iza tion of
2,2-Dip h en yl-1-Meth ylen ecyclop r op a n ea
% yieldb of product
entry
hydrosilane
time/h
1
2
3
1c
2
3
HSiEt3
HSiEt3
HSiEt2Ph
HSi(OEt)Me2
HSi(OEt)2Me
3
3
1
1
1
3
16
16
16
31
26
8
0
0
0
0
0
0
0
49
70
79
92
82
80
22
64
0
0
0
0
0
0
0
7
0
4
5
6d
7e
8
HSi(OEt)3
none
9
a
Reactions of methylenecyclopropanes with hydrosilanes (1:1)
were carried out in the presence of 3 mol % of Pt(PEt3)3 in toluene
b
at 110 °C. The yields were determined by 1H NMR based on
a
Reagents: (i) CuF2‚2H2O, Et2O, 0 °C, 2 h. (ii) EtOH, NEt3, rt,
diphenylmethane as an internal standard. c Methylenecyclopro-
16 h. (iii) H2O2, KF, KHCO3, rt, 12 h.
d
pane:hydrosilane ) 1:2. Methylenecyclopropane:hydrosilane )
1:0.25. e Methylenecyclopropane:hydrosilane ) 1:0.03.
methylenecyclopropane and 2-(4-methoxyphenyl)-1-meth-
ylenecyclopropane react with HSiEt3 to give the ring-
opened products 2i and 2j exclusively (entries 10 and 11).
The reactions of (diphenylmethylene)cyclopropane and
of (3-phenylpropylidene)cyclopropane with HSiEt3 afford
the ring-opened products 2k 8 (58%) and 2l (81%) (eq 1),
P t(P Et3)3-Ca ta lyzed Rin g-Op en in g Isom er iza tion
of Meth ylen ecyclop r op a n es. Use of Pt(PEt3)3 as the
catalyst in the presence of HSiR3 causes conversion of
2,2-diphenyl-1-methylenecyclopropane into 1,1-diphenyl-
1,3-butadiene (3) as the main product (eq 2). The results
of the reactions with several organosilanes are sum-
marized in Table 3. The reaction of 2,2-diphenyl-1-meth-
ylenecyclopropane with HSiEt3 (1:2 molar ratio) gave the
mixture of hydrosilylated product 1a and 3 (entry 1),
while 3 was formed in 70% yield by the same reaction
using equimolar HSiEt3 to 2,2-diphenyl-1-methylenecy-
clopropane (entry 2). Introduction of a Ph or OEt group
at the Si center facilitates the ring-opening isomerization;
addition of HSiEt2Ph or HSi(OEt)Me2 converts 2,2-
diphenyl-1-methylenecyclopropane into 3 selectively (en-
try 4). The reaction in the presence of HSi(OEt)Me2 (100
and 25 mol %) produces 3 in 82% and 80% (entries 5 and
6), although the yield of 3 decreases to 22% in the
presence of 3 mol % of HSi(OEt)2Me (entry 7). Without
the organosilanes, the ring-opening isomerization does
not take place at all (entry 9). These results indicate
incorporation of the organosilanes in the above ring-
opening isomerization.
Scheme 3 depicts a plausible pathway of the reaction.
The cyclopropylmethylplatinum complex is formed via
insertion of 2,2-diphenyl-1-methylenecyclopropane into
the Pt-H bond of an intermediate complex, PtH(SiR3)-
(PEt3)2. â-Alkyl elimination19 of the complex cleaves a
proximal C-C bond of the cyclopropyl ring. Subsequent
â-hydrogen elimination of the 1,1-diphenyl-3-butenyl-
platinum intermediate produces 3 and regenerates PtH-
(SiR3)(PEt3)2.
similar to the findings of Beletskaya et al. in the reaction
catalyzed by RhCl(PPh3)3, RhCl(CO)(PPh3)2, or Rh2Cl2-
(C4H6)4.8 (Butylpentylidene)cyclopropane does not un-
dergo hydrosilylation. Preferential formation of the above
products suggests the selective proximal bond cleavage
during the hydrosilylation.
Trichlorosilylated product of the reaction, 1e, is trans-
formed into functionalized cyclopropane derivatives, as
shown in Scheme 2. Fluorination of 1e using CuF2‚2H2O
gives [(2,2-diphenylcyclopropyl)methyl]trifluorosilane (4)
in 80% yield.15 [(2,2-Diphenylcyclopropyl)methyl]tri-
ethoxysilane (5), which is not formed by the direct
hydrosilylation of 2,2-diphenylmethylenecyclopropane
with HSi(OEt)3 (Table 2, entry 5), is obtained by the
reaction of 1e with EtOH in 77% yield.15 Oxidation of 1e
with hydrogen peroxide by Tamao’s method16 gives 2,2-
diphenylcyclopropylmethanol (6)17 in 76% yield, in which
the cyclopropane ring remains intact. These compounds
4 and 5 cannot be prepared directly by alternative
methods such as cyclopropanation of the allylsilanes.18
(15) Tamao, K.; Kakui, T.; Akita, M.; Iwahara, T.; Kanatani, R.;
Yoshida, J .; Kumada, M. Tetrahedron 1983, 39, 983-990.
(16) (a) Tamao, K.; Ishida, N.; Tanaka, T.; Kumada, M. Organome-
tallics 1983, 2, 1694-1696. (b) Tamao, K.; Ishida, N. J . Organomet.
Chem. 1984, 269, C37-C39. (c) Tamao, K.; Nakajo, E.; Ito, Y. J . Org.
Chem. 1987, 52, 4412-4414. (d) Tamao, K. In Organosilicon and
Bioorganosilicon Chemistry; Sakurai, H., Ed.; Ellis Horwood: Chich-
ester, 1985; pp 231-242.
(18) As for the synthesis of cyclopropylmethylsilanes from allylsi-
lanes, see: Fleming, I.; Sanderson, P. E.; Terrett, N. K. Synthesis 1992,
69-74.
(17) Turnbull, M. D. Perkin Trans. 1 1997, 1241-1247.
J . Org. Chem, Vol. 67, No. 20, 2002 6891

Itazaki et al.
SCHEME 3
that the two products are formed from independent
pathways from each other. Use of PtI2(PPh3)2 in 20 mol
% in the reaction revealed conversion of the starting
21
complex into Pt(H)I(PPh3)2 and formation of the sily-
lated product 1a (85%) and Et3Si-SiEt3 (19%) (eq 4).22
A stoichiometric reaction of 2,2-diphenyl-1-methyl-
enecyclopropane with Pt(H)I(PPh3)2 causes the ring-
opening isomerization to afford 3 in 61% yield at 110 °C
(eq 3). The product 3 is formed by insertion of the CdC
The equimolar reaction between PtI2(PPh3)2 and HSiEt3
led to formation of Pt(H)I(PPh3)2 (51%) and Et3Si-SiEt3
(70%) (eq 5). PtCl2(PPh3)2 was converted into Pt(H)Cl-
bond into a Pt-H bond, the subsequent C-C bond
cleavage to form a 3-butenylplatinum complex, and
â-hydrogen elimination similarly to the reaction path in
Scheme 3. Analogous ring-opening isomerization of 2,2-
diphenyl-1-methylenecyclopropane to 3 was found to be
promoted by RhH(CO)(PPh3)3 by our group.12 All these
results suggest that the ring-opening isomerization pro-
moted by the hydridoplatinum(II) and the hydridorhod-
ium(I) complexes proceeds via the initial CdC bond
insertion into the metal hydrido bond, while many ring-
opening isomerization promoted by transition metal
complexes has been accounted for an alternative pathway
from direct oxidative addition of three-membered ring to
transition metal.20
(PPh3)2 during the reaction more slowly than PtI2(PPh3)2.
The formation of Pt(H)X(PPh3)2 (X ) Cl, I) is ascribed
to the reaction of HSiEt3 with PtI2(PPh3)2 to generate
XSiEt3. Coupling of Cl and SiR3 ligands in Ir(III) and
Pt(IV) complexes was previously proposed to account for
the reaction of excess hydrosilanes with chloro complexes
of Ir(I) and Pt(II).23 We recently reported the reductive
elimination of ClSiR3 and of ISiR3 in thermal reaction of
Rh(III) complexes with halogeno and SiR3 ligands.24
Scheme 4 summarizes the mechanism of the hydrosi-
lylation and isomerization in this study. Both reactions
are initiated by insertion of the CdC bond of methyl-
enecyclopropanes into the Pt-H bond to give intermedi-
ate A. Direct reductive elimination of 1 takes place
preferentially when PtI2(PPh3)2 and 2,2-diaryl-1-meth-
ylenecyclopropanes are used as the catalyst and sub-
strate. Retention of the cyclopropyl group during the Pt-
catalyzed hydrosilylation is explained by the Thorpe-
Ingold effect, which suggests high thermodynamic stability
of 3,3-disubstituted cyclopropanes.25 Cleavage of the C-C
proximal bonds i and ii of the intermediate A by â-alkyl
elimination affords the intermediates B and C, respec-
tively. â-Hydrogen elimination of 3 from 3-butenyl ligand
Rea ction Mech a n ism . Several reactions were con-
ducted in order to obtain further insights into the
mechanism of the hydrosilylation of 2,2-diphenyl-1-
methylenecycropropane catalyzed by PtI2(PPh3)2. The
1
reaction was monitored by H NMR in toluene-d8 at 110
°C, showing a short induction period (15 min) before
parallel increase of 1a and 3. It suggests that the starting
PtI2(PPh3)2 is converted into PtH(I)(PPh3)2, the active
species of the catalyst, during the induction period and
(19) For â-alkyl elimination of the late transition metal complexes,
see: Murakami, M.; Ito, Y. In Activation of Unrective Bonds and
Organic Synthesis; Murai, S., Eds; Springer-Verlag: Berlin, 1999; Vol.
3, pp 97-129. See also: (a) Thomson, S. K.; Young, G. B. Organome-
tallics 1989, 8, 2068-2070. (b) Thomas, B. J .; Noh, S. K.; Schulte, G.
K.; Sendlinger, S. C.; Theopold, K. H. J . Am. Chem. Soc. 1991, 113,
893-902. (c) Alkianiec, B.; Christou, V.; Hardy, D. T.; Thomson, S.
K.; Young, G. B. J . Am. Chem. Soc. 1994, 116, 9963-9978. (d) Suzuki,
H.; Tanaka, M.; Takemori, T. J . Am. Chem. Soc. 1994, 116, 10779-
10780. (e) Rybtchinski, B.; Vigalok, A.; Ben-David, Y.; Milstein, D. J .
Am. Chem. Soc. 1996, 118, 12406-12415. (f) Hartwig, J . F.; Andersen,
R. A.; Bergman, R. G. J . Am. Chem. Soc. 1989, 111, 2717-2719. (g)
McNeill, K.; Andersen, R. A.; Bergman, R. G. J . Am. Chem. Soc. 1997,
119, 11244-11254. (h) Kaplan, A. W.; Bergman, R. G. Organometallics
1997, 16, 1106-1108.
(21) Grushin, V. V.; Akhrem, I. S.; Vol’pin M. E. J . Organomet.
Chem. 1989, 371, 403-419.
(22) The formation of Et3Si-SiEt3 was reported in the reaction of
an excess amounts of HSiEt3 with IrX(CO)(dppe); see: J ohnson, C.
E.; Eisenberg, R. J . Am. Chem. Soc. 1985, 107, 6531-6540.
(23) (a) Chalk, A. J .; Harrod, J . F. J . Am. Chem. Soc. 1965, 87, 16-
21. (b) Ojima, I.; Fuchikami, T.; Yatabe, M. J . Organomet. Chem. 1984,
260, 335-346. (c) Sakaki, S.; Mizoe, N.; Sugimoto, M. Organometallics
1998, 17, 2510-2523.
(20) (a) Brown, J . M.; Kent, A. G. J . Chem. Soc., Perkin Trans. 2
1987, 1597-1607. (b) Chiusoli, G. P.; Costa, M.; Meli, L. J . Organomet.
Chem. 1988, 358, 495-505.
(24) Nishihara, Y.; Takemura, M.; Osakada, K. Organometallics
2002, 21, 825-831.
6892 J . Org. Chem., Vol. 67, No. 20, 2002

Catalyzed Reaction of Methylenecyclopropanes
atmosphere. Methylenecyclopropanes,26 PtI2(PPh3)2,27 and Pt-
28
(PEt3)3 were prepared according to the literature methods.
Rep r esen ta tive P r oced u r e for Hyd r osilyla tion of
Meth ylen ecyclop r op a n e: P r ep a r a tion of [(2,2-Dip h en yl-
cyclop r op yl)m eth yl]tr ieth ylsila n e (1a ). A mixture of 2,2-
diphenyl-1-methylenecyclopropane (619 mg, 3 mmol) and
triethylsilane (698 mg, 6 mmol), and PtI2(PPh3)2 (87 mg, 0.09
mmol, 3 mol %) were heated at 140 °C under argon in a
pressure vial. The reaction mixture was diluted with ether and
passed through a Celite pad to remove insoluble materials.
Evaporation of volatiles afforded a brown oil. Column chro-
matography (silica gel, hexane, Rf ) 0.56) followed by bulb-
to-bulb distillation (180-190 °C/3 Torr) gave 1a (840 mg, 87%
yield) as a colorless oil. 1H NMR (300 MHz, CDCl3): δ ) -0.11
(dd, J ) 14.7 Hz, 11.7 Hz, 1H), 0.69 (q, J ) 8.0 Hz, 6H), 1.05
(t, J ) 8.0 Hz, 9H), 1.05-1.10 (overlapped, 1H), 1.24 (dd, J )
6.0 Hz, 5.1 Hz, 1H), 1.47 (dd, J ) 8.7 Hz, 5.1 Hz, 1H), 1.71
(dddd, J ) 11.7 Hz, 8.7 Hz, 6.0 Hz, 3.0 Hz, 1H), 7.20-7.48 (m,
10H). 13C NMR (75.3 MHz, CDCl3): δ ) 3.50, 7.46, 13.49,
22.74, 23.05, 35.25, 125.38, 126.12, 127.40, 128.12, 131.02,
141.79, 147.83. Anal. Calcd for C22H30Si: C, 81.92; H, 9.37.
Found: C, 81.91; H, 9.12.
F IGURE 1.
SCHEME 4
Syn th esis of (2,2-Diph en yl-3-bu ten yl)tr ieth ylsilan e (2a).
A mixture of 2,2-diphenyl-1-methylenecyclopropane (619 mg,
3 mmol) and triethylsilane (698 mg, 6 mmol) was heated at
110 °C in 7 mL of toluene in the presence of Pt-C (10%) (176
mg, 0.09 mmol, 3 mol %). The reaction mixture was diluted
with hexane and passed through a Celite pad to remove
insoluble materials. Evaporation of volatiles and subsequent
column chromatography (silica gel, hexane, Rf ) 0.58) gave a
colorless oil. Bulb-to-bulb distillation (180-190 °C/3 Torr) gave
1
2a (381 mg, 40% yield) as a colorless oil. H NMR (300 MHz,
CDCl3): δ ) 0.28 (q, J ) 8.4 Hz, 6H), 0.81 (t, J ) 8.4 Hz, 9H),
1.73 (s, 2H), 4.59 (dd, J ) 17.4 Hz, 1.5 Hz, 1H), 5.15 (dd, J )
10.5 Hz, 1.5 Hz, 1H), 6.58 (dd, J ) 17.4 Hz, 10.5 Hz, 1H), 7.16-
7.29 (m, 10H). 13C NMR (75.3 MHz, CDCl3): δ ) 4.47, 7.46,
24.59, 52.65, 114.30, 125.82, 127.68, 128.28, 146.44, 148.65.
Anal. Calcd for C22H30Si: C, 81.92; H, 9.37. Found: C, 81.94;
H, 9.30.
[(2,2-Diph en ylcyclopr opyl)m eth yl]tr iph en ylsilan e (1b)
was isolated as a white solid (53% yield). Rf ) 0.10 (hexane).
of C generates the hydridoplatinum complex, whereas
the intermediate B, which does not undergo â-hydrogen
elimination, causes coupling of the silyl and 3-butenyl
ligands, leading to the open-chain silylated product 2. The
use of Pt(PEt3)3 catalyst leads preferentially to the
formation of 3 via intermediate C. Since other possible
Pt species A′ and A′′ via addition of the H-Pt or Si-Pt
bond to the CdC bond of 2,2-diphenyl-1-methylenecyclo-
propane give neither product 1 nor 2, they are not related
to the reactions in this study (Figure 1). The reaction of
the substrate with alkyl substituents at the 2-position
of the cyclopropane ring or monosubstituted methyl-
enecyclopropanes causes the hydrosilylation with ring-
opening to produce 2.
In summary, we discovered a new methodology to
prepare (cyclopropylmethyl)silanes via hydrosilylation of
2,2-disubstituted methylenecyclopropanes with various
hydrosilanes. The results of this study suggest addition
of other compounds to the CdC bond of substituted
methylenecyclopropanes, which would produce many new
cyclopropane derivatives.
1
Mp: 157-158 °C. H NMR (300 MHz, CDCl3): δ ) 0.77 (dd, J
) 15.6 Hz, 11.4 Hz, 1H), 1.14 (t, J ) 5.1 Hz, 1H), 1.28 (dd, J
) 9.3 Hz, 5.1 Hz, 1H), 1.85 (dd, J ) 15.6 Hz, 3.3 Hz, 1H), 1.82-
1.93 (m, 1H), 7.11-7.62 (m, 25H). 13C NMR (75.3 MHz,
CDCl3): δ ) 15.09, 22.05, 23.23, 35.90, 125.48, 126.26, 127.63,
127.82, 128.07, 128.25, 129.43, 130.86, 135.02, 135.76, 141.50,
147.40. Anal. Calcd for C34H30Si: C, 87.50; H, 6.48. Found:
C, 87.28; H, 6.49.
[(2,2-Dip h e n ylcyclop r op yl)m e t h yl]d ie t h ylp h e n yl-
sila n e (1c) was isolated as a colorless oil (85% yield). Rf )
0.43 (hexane:ethyl acetate ) 10:1). Bp: 210 °C/3 Torr. 1H NMR
(300 MHz, CDCl3): δ ) 0.11 (dd, J ) 15.0 Hz, 11.4 Hz, 1H),
0.86-1.08 (m, 10H), 1.15 (dd, J ) 6.0 Hz, 4.8 Hz, 1H), 1.27
(dd, J ) 15.0 Hz, 3.0 Hz, 1H), 1.35 (dd, J ) 8.7 Hz, 4.8 Hz,
1H), 1.67 (dddd, J ) 11.4 Hz, 8.7 Hz, 6.0 Hz, 3.0 Hz, 1H), 7.13-
7.57 (m, 15H). 13C NMR (75.3 MHz, CDCl3): δ ) 3.67, 3.84,
7.41, 7.46, 13.97, 22.37, 22.93, 35.33, 125.41, 126.16, 127.47,
127.67, 128.09, 128.16, 128.79, 130.93, 134.19, 137.18, 141.69,
147.63. Anal. Calcd for C26H30Si: C, 84.26; H, 8.16. Found:
C, 84.19; H, 8.11.
[(2,2-D ip h e n y lc y c lo p r o p y l)m e t h y l]d ic h lo r o p h e n -
ylsila n e (1d ) was isolated as a pale yellow oil (81% yield).
1
Bp: 220 °C/3 Torr. H NMR (300 MHz, CDCl3): δ ) 0.64 (dd,
J ) 15.0 Hz, 10.8 Hz, 1H), 1.25 (t, J ) 5.4 Hz, 1H), 1.39 (dd,
J ) 8.7 Hz, 5.4 Hz, 1H), 1.72 (dd, J ) 15.0 Hz, 3.6 Hz, 1H),
Exp er im en ta l Section
All manipulations of the complexes were carried out using
standard Schlenk techniques under an argon or a nitrogen
(26) Arona, S.; Binger P. Synthesis 1974, 801-803.
(27) Kistner, C. R.; Hutchinson, J . H.; Doyle, J . R.; Storlie J . C. Inorg.
Chem. 1963, 2, 1255-1261.
(28) (a) Gerlach, D. H.; Kane, A. R.; Parshall, G. W.; J esson, J . P.;
Muetterties, E. L. J . Am. Chem. Soc. 1971, 93, 3543-3544. (b) Yoshida,
T.; Matsuda, T.; Otsuka, S. Inorg. Synth. 1979, 19, 107-110.
(25) (a) Beesley, R. M.; Ingold, C. K.; Thorpe, J . F. J . Chem. Soc.
1915, 107, 1080-1106. (b) Ingold, C. K. J . Chem. Soc., 1921, 119, 305,
951-970. (c) Kon, G. A. R.; Steveson, A.; Thorpe, J . F. J . Chem. Soc.
1922, 121, 650-665.
J . Org. Chem, Vol. 67, No. 20, 2002 6893

Itazaki et al.
1.82 (m, 1H), 7.11-7.35 (m, 10H), 7.42-7.52 (m, 3H), 7.70-
7.73 (m, 2H). 13C NMR (75.3 MHz, CDCl3): δ ) 20.05, 21.98,
22.77, 35.16, 125.83, 126.61, 127.60, 128.23, 128.31, 128.44,
130.71, 131.63, 132.44, 133.44, 140.89, 146.58. Anal. Calcd for
129.55, 148.99, 149.31. 13C NMR (75.3 MHz, CDCl3) for 2h : δ
) 4.60, 7.40, 19.95, 22.81, 43.28, 110.24, 125.09, 126.28, 127.97,
144.13, 149.26. Anal. Calcd for C17H28Si: C, 78.38; H, 10.61.
Found: C, 78.23; H, 10.61.
C
22H20Cl2Si: C, 68.92; H, 5.26. Found: C, 69.31; H, 5.49.
[(2,2-Dip h en ylcyclop r op yl)m eth yl]tr ich lor osila n e (1e)
(2-P h en yl-3-bu ten yl)tr ieth ylsila n e (2i) was isolated as
a colorless oil (57% yield). Rf ) 0.68 (hexane). Bp: 140 °C/3
1
Torr. H NMR (300 MHz, CDCl3): δ ) 0.43-0.52 (dq, J ) 8.1
was isolated as a colorless oil (81% yield). Bp 150 °C/3 Torr.
1H NMR (300 MHz, CDCl3): δ ) 0.68 (dd, J ) 15.3 Hz, 10.8
Hz, 1H), 1.36 (t, J ) 4.8 Hz, 1H), 1.46 (dd, J ) 9.0 Hz, 5.3 Hz,
1H,), 1.76 (dd, J ) 15.3 Hz, 5.3 Hz, 1H), 1.78-1.92 (m,
overlapped, 1H), 7.22-7.48 (m, 10H). 13C NMR (75.3 MHz,
CDCl3): δ ) 19.37, 21.54, 26.09, 35.20, 126.04, 126.84, 127.57,
128.32, 128.57, 130.60, 140.49, 146.08. Anal. Calcd for C16H15
Cl3Si: C, 56.23; H, 4.42; Cl, 31.12. Found: C, 56.34; H, 4.66;
Cl, 30.94.
Hz, 4.2 Hz, 6H), 0.93 (t, J ) 8.1 Hz, 9H), 1.12 (d, J ) 7.8 Hz,
2H), 3.46 (dt, J ) 7.8 Hz, 7.8 Hz, 1H), 4.98 (ddd, J ) 9.9 Hz,
1.5 Hz, 0.9 Hz, 1H), 5.06 (dt, J ) 17.1 Hz, 1.5 Hz, 1H), 6.04
(ddd, J ) 17.1 Hz, 9.9 Hz, 7.8 Hz, 1H), 7.20-7.36 (m, 5H). 13
C
NMR (75.3 MHz, CDCl3): δ ) 3.63, 7.34, 18.44, 45.76, 112.30,
126.06, 127.31, 128.35, 145.00, 146.56. Anal. Calcd for C16H22
Si: C, 77.97; H, 10.63. Found: C, 77.80; H, 10.37.
-
-
(2-p-Meth oxyp h en yl-3-bu ten yl)tr ieth ylsila n e (2j) was
isolated as a colorless oil (37% yield). Rf ) 0.60 (hexane:ethyl
acetate ) 10:1). Bp: 120 °C/3 Torr. 1H NMR (300 MHz,
CDCl3): δ ) 0.39-0.48 (dq, J ) 8.1 Hz, 4.5 Hz, 6H), 0.89 (t, J
) 8.1 Hz, 9H), 1.05 (d, J ) 7.5 Hz, 2H), 3.38 (dt, J ) 7.5 Hz,
1H), 3.80 (s, 3 H), 4.91 (ddd, J ) 9.9 Hz, 1.5 Hz, 1H), 4.98
(ddd, J ) 17.1 Hz, 1.5 Hz, 1H), 5.97 (m, J ) 17.1 Hz, 9.9 Hz,
1H), 6.84 (d, J ) 9.0 Hz, 2H), 7.14 (d, J ) 9.0 Hz, 2H). 13C
NMR (75.3 MHz, CDCl3): δ ) 3.65, 7.35, 18.44, 44.84, 55.24,
111.88, 113.74, 128.19, 138.64, 145.39, 157.93. Anal. Calcd for
[2,2-Bis(4-flu or op h en yl)cyclop r op ylm et h yl]t r iet h yl-
sila n e (1f) was isolated as a colorless oil (80% yield). Rf )
0.39 (hexane). Bp: 180 °C/3 Torr. H NMR (300 MHz, CDCl3):
1
δ ) -0.30 (dd, J ) 15.0 Hz, 11.7 Hz, 1H), 0.55 (q, J ) 8.1 Hz,
6H), 0.87-0.93 (overlapped, 1H), 0.91 (t, J ) 8.1 Hz, 9H), 1.04
(dd, J ) 6.0 Hz, 4.5 Hz, 1H), 1.27 (dd, J ) 8.7 Hz, 4.5 Hz, 1H),
1.51 (dddd, J ) 11.7 Hz, 8.7 Hz, 6.0 Hz, 3.0 Hz, 1H), 6.86-
6.92 (m, 2H), 6.96-7.02 (m, 2H), 7.06-7.11 (m, 2H), 7.23-
7.27 (m, 2H). 13C NMR (75.3 MHz, CDCl3): δ ) 3.46, 7.44,
13.41, 22.47, 22.93, 34.00, 114.85 (d, J ) 21 Hz), 115.13 (d,
J C-F ) 21 Hz), 128.90 (d, J C-F ) 8 Hz), 132.18 (d, J C-F ) 8
Hz), 137.50 (d, J C-F ) 3 Hz), 143.30 (d, J C-F ) 3 Hz), 159.56
(d, J C-F ) 244 Hz), 162.80 (d, J C-F ) 244 Hz). Anal. Calcd for
C
17H28Si: C, 73.85; H, 10.21. Found: C, 73.44; H, 10.07.
(4,4-Dip h en yl-3-bu ten yl)tr ieth ylsila n e (2k ) was isolated
as a colorless oil (58% yield). Rf ) 0.45 (hexane). Bp: 185 °C/3
Torr. 1H NMR (300 MHz, CDCl3): δ ) 0.49 (q, J ) 8.0 Hz,
6H), 0.71 (m, 2H), 0.91 (t, J ) 8.0 Hz, 9H), 2.13 (m, 2 H), 6.16
(t, J ) 7.7 Hz, 1H), 7.19-7.42 (m, 10H). 13C NMR (75.3 MHz,
CDCl3): δ ) 3.24, 7.36, 11.97, 24.04, 126.64, 126.80, 127.15,
128.04, 128.07, 129.89, 133.01, 139.95, 140.18, 142.88. Anal.
Calcd for C22H30Si: C, 81.92; H, 9.37. Found: C, 81.54; H, 9.40.
C
22H28F2Si: C, 73.70; H, 7.87; F, 10.60. Found: C, 74.11; H,
7.86; F, 10.10.
[2,2-B is (p h e n y le t h y l)c y c lo p r o p y lm e t h y l]t r ie t h y l-
sila n e (1g) was isolated as a colorless oil (46% yield). Rf )
0.35 (hexane). Bp: 220 °C/3 Torr. H NMR (300 MHz, CDCl3):
1
δ ) -0.14 (t, J ) 4.4 Hz, 1H), 0.24 (dd, J ) 14.7 Hz, 10.2 Hz,
1H), 0.43-0.56 (m, 2H), 0.55 (q, J ) 8.0 Hz, 6H), 0.84 (dd,
J ) 14.7 Hz, 3.0 Hz, 1H), 0.93 (t, J ) 8.0 Hz, 9H), 1.43-1.80
(m, 4H), 2.60-2.83 (m, 4H), 7.13-7.30 (m, 10H). 13C NMR
(75.3 MHz, CDCl3): δ ) 3.47, 7.51, 10.74, 19.85, 20.42, 23.65,
32.87, 33.08, 33.41, 40.03, 125.61, 125.63, 128.28, 128.32,
142.91, 143.20. Anal. Calcd for C26H38Si: C, 82.47; H, 10.11.
Found: C, 82.57; H, 9.85.
Tr ieth yl(6-p h en yl-3-h exen yl)sila n e (2l) was isolated in
81% yield as a colorless oil. Rf ) 0.74 (hexane). Bp: 155 °C/3
Torr. 1H NMR (300 MHz, CDCl3): δ ) 0.56 (q, J ) 8.1 Hz,
6H), 0.63 (m, 2H), 0.98 (t, J ) 8.1 Hz, 9H), 2.04 (m, 2H), 2.34
(m, 2H), 2.72 (dd, J ) 10.2, 8.1 Hz, 2H), 5.48 (dt, J ) 15.3 Hz,
6.3 Hz, 1H), 5.56 (dt, J ) 15.3 Hz, 6.3 Hz, 1H), 7.20-7.35 (m,
5H). 13C NMR (75.3 MHz, CDCl3): δ ) 3.35, 7.43, 11.32, 26.78,
34.39, 36.16, 125.67, 127.70, 128.22, 128.44, 134.05, 142.24.
Anal. Calcd for C18H30Si: C, 78.75; H, 11.01. Found: C, 78.63;
H, 10.80.
[2,2-Bis(2-p h en ylet h yl)-3-b u t en yl]t r iet h ylsila n e (2g)
was isolated as a colorless oil (40% yield). Rf ) 0.45 (hexane).
1
Bp: 220 °C/3 Torr. H NMR (300 MHz, CDCl3): δ ) 0.64 (q, J
F lu or in a tion of 1e: Syn th esis of [(2,2-Dip h en ylcyclo-
p r op yl)m eth yl]tr iflu or osila n e (4). To a suspension of CuF2‚
2H2O (2.06 g, 15 mmol) in diethyl ether (20 mL) in a 50 mL of
Schlenk tube was added slowly 1e (1.71 g, 5.00 mmol) at 0
°C, and the mixture was stirred at ambient temperature for 2
h under Ar atmosphere. The reaction mixture was diluted with
diethyl ether and passed through a Celite pad to remove
insoluble materials. Evaporation of volatiles afforded a brown
oil, which was subjected to bulb-to-bulb distillation (130-140
°C/3 Torr), giving 4 (1.17 g, 80% yield) as a colorless oil. 1H
NMR (300 MHz, CDCl3): δ ) 0.50 (ddq, J ) 15.9 Hz, 10.2 Hz,
J H-F ) 3.0 Hz, 1H), 1.24-1.33 (m, overlapped, 1H), 1.32 (t, J
) 5.1 Hz, 1H), 1.48 (dd, J ) 8.7 Hz, 5.1 Hz, 1H), 1.84 (m, 1H),
7.18-7.43 (m, 10H). 13C NMR (75.3 MHz, CDCl3): δ ) 9.11
(q, J C-F ) 18 Hz), 17.66, 21.11, 36.03, 126.09, 126.86, 127.67,
128.34, 128.60, 130.59, 140.25, 146.07. 19F NMR (282.3 MHz,
CDCl3): δ ) -137.14 (satellite, J Si-F ) 286 Hz). IR (KBr):
) 7.8 Hz, 6H), 0.93 (s, 2H), 0.99 (t, J ) 7.8 Hz, 9H), 1.77-
1.83 (m, 4H), 2.57-2.63 (m, 4H), 5.05 (dd, J ) 17.7 Hz, 1.5
Hz, 1H), 5.12 (dd, J ) 11.1 Hz, 1.5 Hz, 1H), 5.88 (dd, J ) 17.7
Hz, 11.1 Hz, 1H), 7.20-7.36 (m, 10H). 13C NMR (75.3 MHz,
CDCl3): δ ) 5.07, 7.59, 22.31, 30.56, 41.13, 42.07, 111.99,
125.66, 128.29, 128.38, 143.08, 147.71. Anal. Calcd for C26H38
Si: C, 82.47; H, 10.11. Found: C, 82.75; H, 10.16.
-
[(2-M e t h y l-2-p h e n y lc y c lo p r o p y l)m e t h y l]t r i e t h -
ylsila n e (1h ) a n d (2-Meth yl-2-p h en yl-3-bu ten yl)tr ieth yl-
sila n e (2h ) were obtained in 67% yield as a mixture in 41
(two diastereomers 1:1):59 (determined by 1H NMR) molar
ratio, respectively. Rf ) 0.71 (hexane). Bp: 145 °C/3 Torr.
Although all of signals in 1H NMR were not assigned, the
characteristic signals indicate the formation of 1h and 2h . 1H
NMR (300 MHz, CDCl3) for 1h (for two diastereomers): δ )
-0.39 (dd, J ) 14.7 Hz, 10.8 Hz, 1H), 0.43-0.47 (m, 1H), 0.54
(q, J ) 8.1 Hz, 6H), 0.63 (q, J ) 8.1 Hz, 6H), 0.65-0.72 (m,
1H), 0.82-0.91 (m, 1H), 0.91-1.04 (m, 1H), 0.93 (t, J ) 8.1
Hz, 9H), 1.00 (t, J ) 8.1 Hz, 9H), 1.01-1.05 (m, 1H), 1.18-
1.30 (m, 4H), 1.39 (s, 3H), 1.49 (s, 3H), 7.15-7.38 (m, 10H).
1H NMR (300 MHz, CDCl3) for 2h : δ ) 0.28-0.34 (m, 1H),
0.42 (dq, J ) 7.8 Hz, 3.5 Hz, 6H), 0.88 (t, J ) 7.8 Hz, 9H),
1.14-1.18 (m, 1H), 1.42 (s, 3H), 5.05 (dd, J ) 10.5 Hz, 1.2 Hz,
1H), 5.08 (dd, J ) 17.1 Hz, 1.2 Hz, 1H), 6.12 (dd, J ) 17.1 Hz,
10.5 Hz, 1H), 7.15-7.28 (m, 5H). 13C NMR (75.3 MHz, CDCl3)
for 1h (for two diastereomers): δ ) 3.41, 3.44, 7.45, 7.49, 11.13,
12.91, 21.43, 22.47, 23.76, 25.70 (overlapped with two carbons),
26.16, 27.80, 28.47, 125.62, 125.67, 126.43, 127.91, 128.14,
3085, 3061, 3027, 2934, 2897, 1599, 1497, 1447, 1219 cm-1
.
Anal. Calcd for C16H15F3Si: C, 65.73; H, 5.17. Found: C, 66.10;
H, 5.23.
Alk oxyla tion of 1e: Syn th esis of [(2,2-Dip h en ylcyclo-
p r op yl)m eth yl]tr ieth oxysila n e (5). To the mixture of 1 mL
of EtOH, 2 mL of Et3N, and 150 mL of pentane was added 1e
(1.02 g, 3.00 mmol) at ambient temperature with vigorous
stirring. The resulting white suspension was stirred for 16 h
and then filtered through a Celite pad. Evaporation of volatiles
afforded a pale yellow oil. Bulb-to-bulb distillation (180-190
°C/3 Torr) gave 5 (0.86 g, 77% yield) as a colorless oil. 1H NMR
(300 MHz, CDCl3): δ ) -0.04 (dd, J ) 15.3 Hz, 10.2 Hz, 1H),
6894 J . Org. Chem., Vol. 67, No. 20, 2002

Catalyzed Reaction of Methylenecyclopropanes
0.93 (dd, J ) 15.3 Hz, 3.9 Hz, 1H), 1.19 (t, J ) 7.2 Hz, 9H),
1.14-1.20 (overlapped, 1H), 1.32 (dd, J ) 9.0 Hz, 4.8 Hz, 1H),
1.68 (dddd, J ) 10.2 Hz, 9.0 Hz, 6.0 Hz, 3.9 Hz, 1H), 3.78 (q,
J ) 7.2 Hz, 6H), 7.05-7.31 (m, 10H). 13C NMR (75.3 MHz,
CDCl3): δ ) 12.51, 18.28, 20.83, 22.50, 35.52, 58.36, 125.46,
126.19, 127.57, 128.07, 128.15, 130.95, 141.43, 147.49. Anal.
Calcd for C22H30O3Si: C, 71.31; H, 8.16. Found: C, 71.56; H,
8.44.
mmol) was added 2,2-diphenyl-1-methylenecyclopropane (5.1
µL, 0.025 mmol). The mixture was heated at 110 °C for 9 h to
give 1,1-diphenyl-1,3-butadiene (3) in 61% yield. Data of 3:
1H NMR (300 MHz, CDCl3): δ ) 5.11 (ddd, J ) 10.2 Hz, 1.8
Hz, 0.9 Hz, 1H), 5.38 (ddd, J ) 16.8 Hz, 1.8 Hz, 0.9 Hz, 1H),
6.43 (ddd, J ) 16.8 Hz, 11.1 Hz, 10.2 Hz, 1H), 6.70 (d, J )
11.1 Hz, 1H), 7.19-7.40 (m, 10H).
Rea ction of 2,2-Dip h en yl-1-m eth ylen ecyclop r op a n e
w ith HSiEt3 in th e P r esen ce of 20 m ol % of P tI2(P P h 3)2
(eq 4). To PtI2(PPh3)2 (97 mg, 0.10 mmol) in a 20 mL of
Schlenk tube were added 2,2-diphenyl-1-methylenecyclopro-
pane (50 µL, 0.5 mmol) and triethylsilane (160 µL, 1.0 mmol).
The reaction mixture was heated at 140 °C. After 1 h, the
reaction mixture were washed with hexane (10 mL × 3 times)
and dried in vacuo to give Pt(H)I(PPh3)2 (66 mg, 0.078 mmol,
78% based on Pt complex). The combined hexane solutions
were concentrated under vacuum to give a brown oil. After
addition of diphenylmethane (42 mg, 0.25 mmol) as an internal
P r ep a r a tion of 2,2-Dip h en ylcyclop r op ylm eth a n ol (6).
To a suspension of KF (1.73 g, 30.0 mmol) and KHCO3 (6.00
g, 60.0 mmol) in 240 mL of THF/MeOH (1:1) was added 1e
(1.71 g, 5.00 mmol) at room temperature and the mixture was
stirred for 1 h. To the resulting white suspension was added
4.98 mL of 30% H2O2 at room temperature. Then the reaction
mixture was vigorously stirred for 12 h. To this reaction
mixture was added 6 g of Na2S2O3‚5H2O and then the entire
mixture was stirred for 1 h. The mixture was filtered through
a Celite plug, and the filter cake was rinsed with 50 mL of
diethyl ether. The filtrate was concentrated under vacuum and
the resulting residue was dissolved in 50 mL of CH2Cl2. After
drying over MgSO4, the volatiles were removed in vacuo to
afford a a colorless liquid. Bulb-to-bulb distillation (190-200
1
standard, H NMR measurement revealed that [(2,2-diphen-
ylcyclopropyl)methyl]triethylsilane (1a; 0.425 mmol, 85% based
on methylenecyclopropane) and hexaethyldisilane (0.094 mmol,
19% based on hydrosilane) were formed.
1
°C/4 Torr) gave 6 (0.856 g, 76% yield) as a pale yellow oil. H
Rea ction of HSiEt3 w ith P tI2(P P h 3)2 (eq 5). To a toluene
(5 mL) solution of PtI2(PPh3)2 (244 mg, 0.25 mmol) was added
HSiEt3 (29 mg, 0.25 mmol). The reaction mixture was heated
at 110 °C for 3 h. The volatiles were evaporated in vacuo to
give the dark brown oily substances, and the addition of
hexane gave a pale brown precipitate, which was washed with
hexane (5 mL × 3) and dried under vacuum to yield a mixture
of the unreacted PtI2(PPh3)2 and PtH(I)(PPh3)2 (0.13 mmol,
51% NMR yield based on Pt complex). From the hexane
extracts hexaethyldisilane was isolated (20 mg, 0.088 mmol,
70% isolated yield based on hydrosilane) as a colorless oil.
NMR (300 MHz, CDCl3): δ ) -1.25 (dd, J ) 9.0 Hz, 5.1 Hz,
1H), 1.35 (t, J ) 5.1 Hz, 1H), 1.64 (br s, 1H, OH), 1.96 (m,
1H), 3.34 (dd, J ) 11.4 Hz, 7.8 Hz, 1H), 3.42 (dd, J ) 11.4 Hz,
6.3 Hz, 1H), 7.09-7.39 (m, 10H). 13C NMR (75.3 MHz,
CDCl3): δ ) 17.89, 27.65, 35.55, 63.69, 125.91, 126.62, 127.77,
128.23, 128.48, 130.06, 141.03, 146.23. Anal. Calcd for
C
16H16O: C, 85.68; H, 7.19. Found: C, 85.65; H, 7.21.
Rea ction of 2,2-Dip h en yl-1-m eth ylen ecyclop r op a n e
w ith Tr ieth ylsila n e on NMR Tu be Sca le. To a toluene-d8
(0.6 mL) solution of PtI2(PPh3)2 (2.9 mg, 3 × 10-3 mmol, 3 mol
%) in an NMR tube were added 2,2-diphenyl-1-methylenecy-
clopropane (206.3 mg, 0.1 mmol) and triethylsilane (23.3 mg,
0.2 mmol). The NMR sample tube was sealed and heated at
110 °C. The NMR spectra were recorded at 110 °C over 200
min. After 200 min, 1a and 3 were formed in 64% and 22%
yield, respectively.
Ack n ow led gm en t. This work was partially sup-
ported by a Grant-in-aid for Scientific Research for
Young Chemists No. 13740412 and for Scientific Re-
search on Priority Areas, “Molecular Physical Chemis-
try” No. 11166221, from the Ministry of Education,
Culture, Sports, Science and Technology, J apan.
Rea ction of 2,2-Dip h en yl-1-m eth ylen ecyclop r op a n e
w ith a n Equ im ola r Am ou n t of P tH(I)(P P h 3)2 (eq 3). To a
toluene-d8 (0.6 mL) solution of PtH(I)(PPh3)2 (21 mg, 0.025
J O020293+
J . Org. Chem, Vol. 67, No. 20, 2002 6895