Silylcarbonylation of vinylsilanes catalyzed by iridium(I) siloxide complexes

Article abstract of DOI:10.1021/om050478h

The iridium siloxide complexes [{Ir(μ-OSiMe₃)(cod)} ₂] (I) and [Ir(cod)(PCy₃)(OSiMe₃)] (II) were used as catalysts in the silylcarbonylation of CH₂=CHSiMe ₃. While complex I effectively catalyzed the highly stereoselective formation of (E)-1-(dimethylphenylsiloxy)-1-(dimethylphenylsilyl)-3- (trimethylsilyl)-1-propene (1a, Me₃SiCH₂CH=C(OSiMe ₂Ph)SiMe₂Ph; yield 82%), complex II led the reaction to stereoselective synthesis of (Z)-1-(dimethylphenylsiloxy)-3-(trimethylsilyl)-1- propene (2a, Me₃SiCH₂CH=CHOSiMe₂Ph; yield 95%). The former product was used for synthesis of the acylsilane (Me ₃SiCH₂CH₂C(O)SiMe₂Ph) (4a; yield 92%), a well-known reagent in organic synthesis. Under a CO atmosphere the cyclooctadiene ligand in both complexes was replaced by CO, and the X-ray structure of [Ir(CO)₂(PCy₃)OSiMe₃] (IV) was resolved.

Full text of DOI:10.1021/om050478h

Organometallics 2005, 24, 6179-6183
6179
Silylcarbonylation of Vinylsilanes Catalyzed by
Iridium(I) Siloxide Complexes
Ireneusz Kownacki, Bogdan Marciniec,* Karol Szubert, and Maciej Kubicki
Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan´, Poland
Received June 10, 2005
The iridium siloxide complexes [{Ir(µ-OSiMe3)(cod)}2] (I) and [Ir(cod)(PCy3)(OSiMe3)] (II)
were used as catalysts in the silylcarbonylation of CH2dCHSiMe3. While complex I effectively
catalyzed the highly stereoselective formation of (E)-1-(dimethylphenylsiloxy)-1-(dimeth-
ylphenylsilyl)-3-(trimethylsilyl)-1-propene (1a, Me3SiCH2CHdC(OSiMe2Ph)SiMe2Ph; yield
82%), complex II led the reaction to stereoselective synthesis of (Z)-1-(dimethylphenylsiloxy)-
3-(trimethylsilyl)-1-propene (2a, Me3SiCH2CHdCHOSiMe2Ph; yield 95%). The former product
was used for synthesis of the acylsilane (Me3SiCH2CH2C(O)SiMe2Ph) (4a; yield 92%), a well-
known reagent in organic synthesis. Under a CO atmosphere the cyclooctadiene ligand in
both complexes was replaced by CO, and the X-ray structure of [Ir(CO)2(PCy3)OSiMe3] (IV)
was resolved.
Introduction
been shown to be efficient catalysts for silylformylation
of alkynes and have been effectively used in systems
with terminal and internal alkynes,6-9 diynes,10 and
enynes,11 giving various unsaturated silyl aldehydes and
cyclic compounds containing a carbonyl moiety. On the
other hand, rhodium-catalyzed incorporation of CO and
organosilane into a CdC bond, e.g. in enamines,12 leads
to formation of enol silyl ethers, exactly as in Murai’s
study (eq 1), but in reactions of homoallylic alcohol
derivatives the aldehydes were observed as products of
intramolecular reaction.13
Catalytic silylcarbonylation of unsaturated com-
pounds has emerged as a promising, most elegant, and
economical synthetic tool for hydrocarbon chain exten-
sion via direct introduction of carbon monoxide into
organic molecules.1 Cobalt-catalyzed carbonylation reac-
tions have been explored by Murai and co-workers.2
Using [Co2(CO)8] as the catalyst, they have introduced
carbon monoxide and trisubstituted silanes into various
organic compounds: e.g. alkenes,3 aldehydes,4 and cyclic
ethers.5 The characteristic point in the reaction of
alkenes in silylcarbonylation is that enol silyl ethers (A)
are formed exclusively, and neither â-silyl aldehyde (B)
nor acylsilane (C) is observed in the reaction mixture
(eq 1).
In contrast to the case for cobalt and rhodium orga-
nometallic precursors, the iridium complexes have not
(6) (a) Matsuda, I.; Ogiso, A.; Sato, S.; Izumi, Y. J. Am. Chem. Soc.
1989, 111, 2332. (b) Matsuda, I.; Ogiso, A.; Sato, S. J. Am. Chem. Soc.
1990, 112, 6120. (c) Matsuda, I.; Sakakibara, J.; Nagashima, H.,
Tetrahedron Lett. 1991, 32, 7431. (d) Matsuda, I.; Sakakibara, J.; Inoue,
H.; Nagashima, H. Tetrahedron Lett. 1992, 33, 5799. (e) Matsuda, I.;
Ishibashi, H.; Ii, N. Tetrahedron Lett. 1995, 36, 241. (f) Monteil, F.;
Matsuda, I.; Alper, H. J. Am. Chem. Soc. 1995, 117, 4419. (g) Ojima,
I.; Vidal, E.; Tzamarioudaki, M.; Matsuda, I. J. Am. Chem. Soc. 1995,
117, 6797. (h) Matsuda, I.; Fukuta, Y.; Tsuchihashi, T.; Nagashima,
H.; Itoh, K. Organometallics 1997, 16, 4327. (i) Matsuda, I.; Fukuta,
Y.; Itoh, K. Inorg. Chim. Acta 1999, 296, 72. (j) Matsuda, I.; Niikawa,
N.; Kuwabara, R.; Inoue, H.; Nagashima, H.; Itoh, K. J. Organomet.
Chem. 1999, 574, 133. (k) Ojima, I.; Vidal, E. S. Organometallics 1999,
18, 5103. (l) Aronica, L. A.; Terreni, S.; Caporusso, A. M.; Salvadori,
P. Eur. J. Org. Chem. 2001, 4321. (m) Alonso, M. A.; Casares, J. A.;
Espinet, P.; Valles, E.; Soulantica, K. Tetrahedron Lett. 2001, 42, 5697.
(n) Okzaki, H.; Kawanami, Y.; Yamamoto, K.; Chem. Lett. 2001, 650.
(7) (a) Ojima, I.; Ingallina, P.; Donovan, R. J.; Clos, N. Organome-
tallics 1991, 10 38. (b) Ojima, I.; Donovan, R. J.; Eguchi, M.; Shay, W.
R.; Ingallina, P.; Korda, A.; Zeng, Q. Tetrahedron 1993, 49, 5431. (c)
Eguchi, M.; Zeng, Q.; Korda, A.; Ojima, I. Tetrahedron Lett. 1993, 34,
915. (d) Ojima, I.; Tzamarioudaki, M.; Tsai, C.-Y. J. Am. Chem. Soc.
1994, 116, 3643.
While cobalt complexes have been intensively studied
in silylcarbonylation reactions, rhodium complexes have
* To whom correspondence should be addressed. Fax: (+48) 61-
8291-508. E-mail: marcinb@amu.edu.pl.
(1) (a) Colquhoun, H. M.; Thompson, D. J.; Twigg, M. V. Carbonyl-
ation: Direct Synthesis of Carbonyl Compounds; Plenum Press: New
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Trost, B. M., Fleming, I., Eds.; Pergamon Press: Oxford, U.K. 1991;
Vol. 3, p 1015.
(2) (a) Murai, S.; Sonoda, N. Angew. Chem., Int. Ed. Engl. 1979,
18, 837. (b) Murai, S., Seki, Y. J. Mol. Catal. 1987, 41, 197. (c) Chatani,
N.; Kajikawa, Y.; Nishimura, H. Murai, S. Organometallics 1991, 10,
21. (d) Chatani, N.; Murai, S. Synlett 1996, 5, 414.
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(b) Doyle, M. P.; Shanklin, M. S. Organometallics 1994, 13, 1081.
(9) Zhou, J.-Q.; Alper, H. Organometallics 1994, 13, 1586.
(10) (a) Ojima, I.; Fracchiolla, D. A.; Donovan, R. J.; Banerji, P. J.
Org. Chem. 1994, 59, 7594. (b) Ojima, I.; Zhu, J.; Vidal, E. S.; Kass, D.
F. J. Am. Chem. Soc. 1998, 120, 6690. (c) Bonafoux, D.; Ojima, I., Org.
Lett. 2001, 3, 1303.
(3) Seki, Y.; Kawamoto, K., Chatani, N.; Hidaka, A., Sonoda, N. Ohe,
K.; Kawaskai, Y.; Murai, S. J. Organomet. Chem. 1991, 403, 73.
(4) Murai, S.; Kato, T., Sonoda, N.; Seki, Y.; Kawamoto, K. J.
Organomet. Chem. 1979, 18, 393.
(5) Murai, T.; Yasui, E.; Kato, S.; Hatayama, Y.; Suzuki, S.;
Yamasaki, Y.; Sonoda, N.; Kurosawa, H.; Kawasaki, Y.; Murai, S. J.
Am. Chem. Soc. 1989, 111, 393.
(11) (a) Fukuta, Y.; Matsuda, I.; Itoh, K. Tetrahedron Lett. 1999,
40, 4703. (b) Ojima, I.; Vu, A. T.; Lee, S.-Y.; McCullagh, J. V.; Moralee,
A. C.; Fujiwara, M.; Hoang, T. H. J. Am. Chem. Soc. 2002, 124, 9164.
(c) Park, K. H.; Jung, I. G.; Kim, S. Y.; Chung, Y. K. Org. Lett. 2003,
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Chem. 1992, 57, 2.
10.1021/om050478h CCC: $30.25 © 2005 American Chemical Society
Publication on Web 11/04/2005

6180 Organometallics, Vol. 24, No. 25, 2005
Kownacki et al.
Table 1. Silylcarbonylation of Vinyltrimethylsilane Catalyzed by Iridium(I) Siloxide Complexes I and IIa
conversn (%)
H2CdCHSiMe3
yield (%)
molar ratio
pressure
[H2CdCHSiMe3]:[HSiMe2Ph]
of CO (bar)
HSiMe2Ph
1a (E:Z)
2a (Z)
3a
11
1:1d
1:1d
1:1d
1:2d
1:2d
1:2d
1:2e
1:1f
1:1f
1:2f
1:1g
10
20
60
20
60c
60b
60
10
60
10
60
99
99
59
98
95
99
87
93
96
97
91
99
99
62
97
96
99
71
91
94
53
89
58 (94:6)
54 (95:5)
52 (93:7)
62 (95:5)
82 (93:7)
80 (94:6)
40 (82:18)
0
30
21
7
25
14
14
8
92
95
97
90
24
trace
11
0
5
23
0
0
0
0
0
0
0
a Conditions: [H2CdCHSiMe3]:[Ir] ) 1:5 × 10-3, argon, 24 h, unless specified otherwise. The product ratios and yields were determined
by GC and GC-MS and were confirmed by 1H NMR spectroscopy. b Conditions: 60 h, T ) 110 °C. c Conditions: 60 h, T ) 80 °C. d [{Ir(µ-
OSiMe3)(cod)}2]. e [{Ir(µ-Cl)(cod)}2]. f [Ir(cod)(PCy3)(OSiMe3)]. g [Ir(CO)2(PCy3)(OSiMe3)].
been commonly used in these transformations. Only a
few reports have been found of iridium-catalyzed incor-
poration of CO and trisubstituted silanes into organic
molecules: e.g. olefins14 and acetylene hydrazones.15
Iridium complexes such as [Ir4(CO)12] and [{Ir(µ-Cl)-
(CO)2}n] catalyze the transformation of olefins to enol
silyl ethers of acylsilanes (eq 2, where R ) Ph, BuO,
(EtO)2CH and R′3 ) Et2Me),14 widely used as substrates
in organic and organosilicon synthesis (for a recent
review see ref 16).
iridium(I) siloxide complexes and examples of their
application in catalytic transformations of organosilicon
compounds, i.e., silylative coupling, codimerization of
vinylsilanes with styrene,17 hydrosilylation of olefins,
and vinylsiloxanes,19 as well as recently in the hydro-
formylation of vinylsilanes20 (for a review see ref 21).
High catalytic efficiency of iridium siloxide complexes
in the addition of hydrosilanes into the carbon-carbon
double bond is important for the application of these
complexes to the simultaneous incorporation of CO and
trisubstituted silanes into olefins.
The aim of this work is to study the performance of
well-defined iridium(I) siloxide precursors in the silyl-
carbonylation of vinylsilanes, in order to get more
comprehensive information on their catalytic activity
and their possible application in the synthesis of enol
silyl ethers of acylsilanes vs enol silyl ethers of alde-
hydes.
The situation is different when the 1,6-acetylene
hydrazones are used as substrates, because in the
presence of the iridium carbonyl cluster [Ir4(CO)12]
seven-membered nitrogen heterocycles with a silyl-
methylene group at the 3-position are formed (eq 3,
where E ) COOEt).15
Results and Discussion
The iridium(I) siloxide complexes [{Ir(µ-OSiMe3)-
(cod)}2] (I) and [Ir(cod)(PCy3)(OSiMe3)] (II) were exam-
ined as catalysts in the reaction of vinyltrisubstituted
silanes with HSiMe2Ph under a carbon monoxide at-
mosphere. The GC-MS analysis shows that the process
occurs according to eq 4.
Recently, we have published details of the synthesis
and X-ray structures of new dimeric17 and monomeric18
(13) (a) Leighton, J. L.; Chapman, E. J. Am. Chem. Soc. 1997, 119,
12416. (b) Denmark, S. E.; Kobayashi, T. J. Org. Chem. 2003, 68, 5153.
(14) Chatani, N.; Ikeda, S.; Ohe, K.; Murai, S. J. Am. Chem. Soc.
1992, 114, 9710.
(15) Chatani, N.; Yamaguchi, S.; Fukumoto, Y., Murai, S. Organo-
metallics 1995, 14, 4418.
(16) (a) Marciniec, B.; Zaidlewicz, M.; Pietraszuk, C.; Kownacki, I.
In Comprehensive Organic Functional Group Transformations II;
Katritzky, A. R., Taylor, R. J. K., Eds.; Elsevier Science: Amsterdam,
2005; Chapter 2.18, pp 941-1023. (b) Gassmann, S.; Guintchin, B.;
Bienz, S. Organometallics 2001, 20, 1849. (c) Saleur, D.; Bouillon, J.-
P.; Portella, C. J. Org. Chem. 2001, 66, 4543. (d) Obora, Y.; Nakanishi,
M.; Tokunaga, M.; Tsuji, Y. J. Org. Chem. 2002, 67, 5835. (e) Linghu,
X.; Nicewicz, D. A.; Johnson, J. S. Org. Lett. 2002, 4, 2957. (f) Shindo,
M.; Matsumoto, K.; Mori, S.; Shishido, K. J. Am. Chem. Soc. 2002,
124, 6840. (g) Lefebvre, O.; Brigaud, T.; Portella, C. J. Org. Chem. 2001,
66, 1941. (h) Obora, Y.; Ogawa, Y.; Imai, Y.; Kawamura, T.; Tsuji, Y.
J. Am. Chem. Soc. 2001, 123, 10489. (i) Takeda, K.; Yamawaki, K.;
Hatakeyama, N. J. Org. Chem. 2002, 67, 1786. (j) Linghu, X.; Potnick,
J. R.; Johnson, J. S. J. Am. Chem. Soc. 2004, 126, 3070. (k) Nicewicz,
D. A.; Yates, C. M.; Johnson, J. S. J. Org. Chem. 2004, 69, 6548. (l)
Mattson, A. E.; Bharadwaj, A. R.; Scheidt, K. A. J. Am. Chem. Soc.
2004, 126, 2314.
Results of the catalytic tests compiled in Tables 1 and
2 show that the yield of the silylcarbonylation products
depends strongly on the reaction conditions, i.e., the
(19) Marciniec, B.; Kownacki, I.; Kubicki, M.; Krzyz˘ anowski, P.;
Walczuk, E.; Błaz˘ ejewska-Chadyniak, P. In Perspectives in Organo-
metallic Chemistry; Screttas, C. G., Steele, B. R., Eds.; Royal Society
of Chemistry: Cambridge, U.K., 2003; p 253.
(20) Mieczyn˜ska, E.; Trzeciak, A. M.; Zio´łkowski, J. J.; Kownacki,
I.; Marciniec, B. J. Mol. Catal. 2005, 237, 246.
(21) Marciniec, B.; Maciejewski, H. Coord. Chem. Rev. 2001, 223,
301.
(17) Marciniec, B.; Kownacki, I.; Kubicki, M. Organometallics 2002,
21, 3263.
(18) Kownacki, I.; Kubicki, M.; Marciniec, B. Inorg. Chim. Acta 2002,
334, 301.

Silylcarbonylation Catalyzed by Ir(I) Siloxides
Organometallics, Vol. 24, No. 25, 2005 6181
Table 2. Reaction of Vinyldimethylphenylsilane
with Dimethylphenylsilane and Carbon Monoxide
in the Presence of Iridium(I) Siloxide Complexes
I and IIa
conversn (%)
yield (%)
molar ratio
[H2CdCHSiMe2Ph]:
[HSiMe2Ph]
pressure
of CO
(bar)
H2CdCHSi- HSiMe2-
Me2Ph
Ph
1b 2b 3b
1:2c
10
60
10
10
94
72
0
99
81
0
31 47 15
40 18 14
1:2c
1:2d
1:2b,d
0
0
0
0
0
80
78
80
a Conditions: [H2CdCHSiMe2Ph]:[Ir] ) 1:5 × 10-3, argon, 24
h, T, ) 120 °C, toluene, unless specified otherwise. b In air.
c [{Ir(cod)(µ-OSiMe3)}2]. d [Ir(cod)(PCy3)(OSiMe3)].
molar ratio of substrates and pressure of the carbon
monoxide, as well as the structure of the catalyst used.
The catalytic activity of the iridium(I) siloxide complexes
was studied in the reaction systems of two vinylsilanes,
vinyltrimethylsilane and vinyldimethylphenylsilane.
The data given in Table 1 indicate that for a mixture
of substrates (a), complex I catalyzes the formation of
the enol silyl ether of the acylsilane (1a) in high yield.
Under the optimal reaction conditions (pCO ) 60 bar, t
) 60 h, T ) 80 °C) and with equimolar quantities of
the substrates, compound 1a was formed with a yield
of 82%, accompanied by 14% of the side product 1b.
However, distillation under vacuum enabled us to
isolate pure 1a (see the Experimental Section). The
siloxy precursor I appeared to be more effective and
selective under conditions milder than for the complexes
used previously ([{Ir(µ-Cl)(CO)2}2], yield ) 53%, E/Z )
79/21, pCO ) 50 bar, T ) 140 °C using 10 equiv of
olefins)2d and also than for the analogous chloro complex
[{Ir(µ-Cl)(cod)}2]. The high efficiency of I can be applied
to the synthesis of acylsilanes, which proceeds via
hydrolysis14 of product 1: e.g., the synthesis of 4a
according to eq 5.
Figure 1. Perspective view of the complex, along with the
numbering scheme. Selected geometrical parameters (dis-
tances in Å and angles in deg), with esd’s in parentheses
are as follows. Distances: C1-Ir1-C2Ir1-C1, 1.827(8);
Ir1-C2, 1.906(8); Ir1-O3, 1.995(5); Ir1-P4, 2.381(1); C1-
O1, 1.146(9); C2-O2, 1.109(10); Si3-O3, 1.607(5); Si3-
C31, 1.843(12); Si3-C32, 1.841(12); Si3-C33, 1.855(11);
P4-C411, 1.836(6); P4-C421, 1.854(7); P4-C431, 1.853(6);
C(sp3)-C(sp3) , 1.52(2). Angles: C1-Ir1-C2, 88.8(3); C1-
Ir1-O3, 176.9(3); C1-Ir1-P4, 91.9(2); C2-Ir1-O3, 94.3(3);
C2-Ir1-P4, 178.5(2); O3-Ir1-P4, 85.0(1); Ir1-C1-O1,
179.2(9); Ir1-C2-O2, 175.2(8); Ir1-O3-Si3, 136.9(3); Ir1-
P4-C411, 112.2(2); Ir1-P4-C421, 111.9(2); Ir1-P4-C431,
110.7(2). The anisotropic displacement ellipsoids are drawn
at the 50% probability level, and hydrogen atoms are
depicted as spheres with arbitrary radii.
reaction conditions has revealed that, in the presence
of CO, the cyclooctadiene ligand is replaced by carbon
monoxide. The synthetic reaction performed according
to eq 7 allowed the isolation of compound IV. Unfortu-
nately, isolation of compound III was not possible,
because during evaporation of the solvent the product
was observed to decompose.
Acylsilanes are useful and are widely used as reagents
in organic synthesis: e.g., acylation of allylic esters or
unsaturated ketones, Z-olefination of acylsilanes etc.,16b-l
and synthesis of organosilicon derivatives.16a
Under the same reaction conditions complex II leads
to exclusive and stereoselective formation of (Z)-1-
(dimethylphenylsiloxy)-3-(trimethylsilyl)propene (2a;
Table 1), which has been isolated and spectroscopically
characterized.
When vinyldimethylphenylsilane (mixture b) was
used instead of vinyltrimethylsilane, the yield of silyl-
carbonylation products dramatically decreased (1b, 2b).
In the presence of complex I and under low pressure of
CO (10 bar) compound 2b was formed as the main
product in 47% yield, but when the system was pres-
surized to 60 bar, a higher yield of compound 1b was
observed, not exceeding 40%. When the precursor II was
used as the catalyst, the hydrosilylation product was
exclusively formed, but only when a small amount of
air was introduced into the reaction system (Table 2).
A preliminary NMR study on transformations of
iridium(I) siloxide precursors under silylcarbonylation
1
The structure of complex IV was determined by H,
13C, 31P, and 29Si NMR spectroscopy and X-ray analysis.
Figure 1 shows a perspective view of the complex with
the numbering scheme.
The coordination of iridium is square planar, as is the
case in the majority of the four-coordinated iridium
complexes. The carbonyl groups are situated cis with
respect to each other, and Ir-C-O angles are close to
180°. Cyclohexyl rings are close to the ideal chair
conformations, and the distortions from the ideal C3v
symmetry are small. The geometry of the siloxy group
is similar to that described for other transition-metal-

6182 Organometallics, Vol. 24, No. 25, 2005
Kownacki et al.
ter23 with graphite-monochromatized Mo KR radiation (λ )
0.710 73 Å). The data were corrected for Lorentz-polarization
effects24 as well as for absorption by SORTAV.25 Accurate unit-
cell parameters were determined by a least-squares fit of 6595
reflections of highest intensity, chosen from the whole experi-
ment. The structure was solved with SHELXS9726 and re-
fined by the full-matrix least-squares procedure on F2 by
SHELXL97.27 Scattering factors incorporated in SHELXL97
siloxy complexes (the mean value of the Si-O bond
length from the 44 fragments is 1.60(2) Å).22
Conclusions
While the iridium siloxide dimeric iridium complex I
appeared to be a very efficient catalyst for the silylcar-
bonylation of vinyltrimethylsilane, giving highly ster-
eoselectively enol silyl ethers of acylsilanes, Me3SiCH2-
CHdC(OSiMe2Ph)SiMe3Ph (1a; 82%, E/Z ) 93/7), the
monomeric iridium siloxide complex II proved to be a
stereoselective catalyst in the exclusive synthesis of the
silyl-substituted enol silyl ether (Z)-Me3SiCH2CHd
CHOSiMe2Ph (2a; yield 95%). Compound 1a can be
effectively used for the synthesis of Me3SiCH2CH2C(O)Si-
Me2Ph (4a; yield 92%).
Under a CO atmosphere, the cyclooctadiene ligand in
complexes I and II is replaced by CO. [Ir(CO)2(PCy3)2-
(OSiMe3)] (IV) was synthesized (yield 70%), and its
square-planar iridium coordination was confirmed by
X-ray crystallography.
2
2
were used. The function ∑w(|Fo| - |Fc| )2 was minimized, with
2
w-1 ) [σ2(Fo)2 + 0.0724P2] (P ) [Max(Fo , 0) + 2Fc2]/3). All
non-hydrogen atoms were refined anisotropically; hydrogen
atoms were placed geometrically, in idealized positions, and
refined as rigid groups. The Uiso values of hydrogen atoms were
set as 1.2 (1.3 for methyl groups) times the Ueq value of the
appropriate carrier atom. Relevant crystal data and data
collection parameters together with structure refinement
details for complex IV are as follows: formula, Ir(CO)2OSi-
(CH3)3P(C6H11)3; formula weight, 617.83; crystal system, tri-
clinic; space group, P1h; a, 9.8328(6) Å; b, 10.2516(6) Å; c,
14.9852(9) Å; R, 80.797(5)°; â, 85.881(5)°; γ, 66.447(6)°; V,
1366.82(14) Å3; Z, 2; Dx, 1.501 g cm-3; F(000), 620; µ, 5.006
mm-1; crystal size, 0.3 × 0.2 × 0.2 mm; θ range, 3.26-27.5°;
hkl range, -12 e h e 12, -13 e k e 13, -19 e l e 19; number
of reflections collected, 13 042; number of unique reflections
(Rint), 6212 (0.074); number of reflections with I > 2σ(I), 5126;
number of parameters, 262; R(F) (I > 2σ(I)), 0.048; Rw(F2) (I
> 2σ(I)), 0.114; R(F) (all data), 0.056; Rw(F2) (all data), 0.119;
Experimental Section
goodness of fit, 1.075; max/min ∆F, 1.27/-3.13 e Å-3
.
General Methods and Chemicals. All synthesis and
manipulations were carried out under argon using standard
Schlenk and vacuum techniques. Pressure reactions were
performed in an autoclave (100 mL, equipped with a PTFE
insert). The catalyst precursors [{Ir(µ-OSiMe3)(cod)}2] (I)17 and
[Ir(cod)(PCy3)(OSiMe3)] (II)18 were synthesized as we described
previously. Column chromatography was carried out with
General Procedure for Silylcarbonylation. A mixture
of CH2dCHSiR3 (3.93 mmol), HSiMe2Ph (3.93 mmol), and 10
mL of dried and deoxygenated benzene or of CH2dCHSiR3
(3.93 mmol), HSiMe2Ph (7.86 mmol), and 20 mL of dried and
deoxygenated toluene with the iridium catalyst (0.01965 mmol)
precursor was prepared in a Schlenk flask under argon. The
solution was transferred by a cannula system into the auto-
clave, which was flushed with argon prior to use. Then the
reactor was pressurized with CO. The reaction mixture was
magnetically stirred at the given temperature for 48-60 h.
After this time the autoclave was cooled to room temperature
and the mixture was analyzed on the GC.
Synthesis of (E)-1-(Dimethylphenylsiloxy)-1-(dimeth-
ylphenylsilyl)-3-(trimethylsilyl)-1-propene (1a, Me3SiCH2-
CHdC(OSiMe2Ph)SiMe2Ph). Portions of CH2dCHSiMe3
(1.572 g, 15.72 mmol) and HSiMe2Ph (4.28 g, 31.44 mmol) were
dissolved in 50 mL of dried and deoxygenated benzene; this
solution and 0.0305 g (0.0393 mmol) of catalyst I were placed
in a Schlenk flask under argon. Then the solution was
transferred by a cannula system into the autoclave, which was
flushed with argon prior to use. The reactor was pressurized
to 60 bar with CO. The reaction mixture was magnetically
stirred at 80 °C for 60 h. After this time the autoclave was
cooled to room temperature. The solvent was removed under
reduced pressure, and the product was isolated by fractional
distillation under vacuum (120 °C/1 mmHg, 72% yield). Anal.
Calcd for C22H34OSi3: C, 66.26; H, 8.59. Found: C, 66.52; H,
9.11. 1H NMR (δ (ppm), C6D6): 0.016 (s, 9H, Me); 0.34 (s, 6H,
Me); 0.36 (s, 6H, Me), 1.56 (d, JH-H ) 8.4 Hz, 2H, -CH2-);
5.24 (t, JH-H ) 8.4 Hz, 1H, -CHd); 7.22, 7.59 (m, 10H, Ph).
13C NMR (δ (ppm), C6D6): -2.74, -1.64, 0.52 (Me); 17.53
(-CH2-); 123.6 (dCH-); 129.43, 129.7, 133.81, 134.66, 138.16,
139.31 (Ph); 153.76 (dC(Si)OSi). 29Si NMR (δ (ppm), C6D6):
-12.68, 1.37, 3.64. MS (m/z (relative intensity)): 400 (6), 399
(8), 398 (31, M•+), 271 (15), 248 (7), 247 (7), 243 (7), 234 (10),
1
silica gel 60 from Fluka. H, 13C, and 29Si NMR spectra were
recorded on Varian Gemini 300 VT and Varian Mercury 300
VT spectrometers in C6D6. The mass spectra of the products
and substrates were determined by GC-MS (Varian Saturn
2100T equipped with a 30 m DB-1 capillary column). GC
analyses were carried out on a Varian 3800 series gas
chromatograph with a 30 m DB-1 capillary column and TCD.
The chemicals were obtained from the following sources:
sodium trimethylsilanolate, benzene-d6, CDCl3, and hydro-
chloric acid diethyl ether solution from Aldrich Chemical Co.,
trisubstituted and vinyl trisubstituted silanes from Gelest Ltd.,
toluene, hexane, and acetone from POCH Gliwice (Poland), and
carbon monoxide from Fluka. All solvents and vinyl-substi-
tuted silanes were dried and distilled under argon prior to use.
Synthesis of the Complex [Ir(CO)2(PCy3)(OSiMe3)]
(IV). A portion of complex II (0.2 g, 0.3 mmol) was dissolved
in 3 mL of dried and deoxygenated benzene in a Schlenk tube.
Then, 10 mL of carbon monoxide was introduced into a
vigorously stirred solution. The reaction was carried out for
0.5 h at room temperature. After that time, the mixture was
filtered off by a cannula system. From the filtrate obtained,
solvent and cyclooctadiene were evaporated. The pale yellow
solid was dissolved in pentane and cooled to -20 °C for
crystallization. The crystals obtained were washed with two
small portions of pentane at -60 °C and dried under vacuum
(yield 0.129 g (70%)). Anal. Calcd for C23H44IrO3PSi: C, 44.57;
1
H, 7.15. Found: C, 44.77; H, 7.91. H NMR (δ (ppm), C6D6):
0.39 (s, 9H, Me); 1.12, 1.55, 1.90, 2.15 (m, 33H, Cy). 13C NMR
(δ (ppm), C6D6): 4.47 (-Me); 26.79, 27.92, 28.06, 30.24, 32.65,
32.99 (-Cy); 176.38, 179.97 (CO). 31P NMR (δ (ppm), C6D6):
32.01 (PCy3). 29Si NMR (δ (ppm), C6D6): 10.64 (-OSiMe3).
(23) CrysAlisCCD, User Guide v.171; Oxford Diffraction Poland Sp.,
Wrocław, Poland, 2003.
(24) CrysAlisRed, CCD data reduction GUI v.171; Oxford Diffraction
Poland Sp., Wrocław, Poland, 2003.
(25) Blessing, R. H. J. Appl. Crystallogr. 1989, 22, 396.
(26) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467.
(27) Sheldrick, G. M. SHELXL-97, Program for the Refinement of
Crystal Structures; University of Go˜ttingen, Go˜ttingen, Germany,
1997.
X-ray Structure Determination of IV. Single crystals of
IV were grown by slow evaporation of pentane from the
solution. Diffraction data were collected at room temperature
by the ω-scan technique, on a KUMA-KM4CCD diffractome-
(22) Allen, F. H. Acta Crystallogr. 2002, B58, 380.

Silylcarbonylation Catalyzed by Ir(I) Siloxides
Organometallics, Vol. 24, No. 25, 2005 6183
233 (41), 211 (30), 210 (24), 209 (100), 195 (10), 194 (22), 193
(24), 149 (17), 148 (6), 147 (23), 136 (11), 135 (18), 117 (5), 107
(8), 105 (6), 75 (5), 73 (31), 45 (12).
this time the solvent was removed under reduced pressure and
product 4a was isolated from the residue on a silica gel column,
where hexane was used as a mobile phase the hexane (yield
0.61 g (92%)). Anal. Calcd for C14H24OSi2: C, 63.57; H, 9.15.
Found: C, 63.69; H, 10.12. 1H NMR (δ (ppm), C6D6): -0.09 (s,
9H, Me); 0.50 (s, 6H, Me); 0.59 (m, 2H, -CH2Sit); 2.52
(-CH2C(O)-); 7.40, 7.56 (Ph). 13C NMR (δ (ppm), C6D6): -4.51
(Me); -1.89 (Me); 8.29 (-CH2Sit); 43.04 (-CH2C(O)-); 128.11,
129.81, 133.94, 134.73 (Ph); 245.92 (-C(O)-). MS (m/z (relative
intensity)): 249 (38), 209 (5), 193 (5), 191 (6), 187 (13), 163
(18), 138 (5), 136 (14), 135 (100), 107 (9), 105 (7), 75 (7), 73
(13), 45 (6).
Synthesis of (Z)-1-(Dimethylphenylsiloxy)-3-(trimeth-
ylsilyl)-1-propene (2a, Me3SiCH2CHdCHOSiMe2Ph). Por-
tions of CH2dCHSiMe3 (1.572 g, 15.72 mmol) and HSiMe2Ph
(2.14 g, 15.72 mmol) were dissolved in 50 mL of dried and
deoxygenated benzene; this solution and 0.053 g (0.079 mmol)
of catalyst II were placed in a Schlenk flask under argon. Then
the solution was transferred by a cannula system into the
autoclave, which was flushed with argon prior to use. The
reactor was pressurized to 60 bar with CO. The reaction
mixture was magnetically stirred at 100 °C for 24 h. After this
time the autoclave was cooled to room temperature. The
solvent was removed under reduced pressure, and the product
was isolated by fractional distillation under vacuum (80 °C/1
mmHg, 90% yield). Anal. Calcd for C14H24OSi2: C, 44.57; H,
9.15. Found: C, 44.83; H, 9.91. 1H NMR (δ (ppm), C6D6): 0.079
(s, 9H, Me); 0.26 (s, 6H, Me); 1.69 (d, JH-H ) 9.3 Hz, 2H,
-CH2-); 4.55 (m, JH-H ) 6.6 Hz and JH-H ) 9.3 Hz, 1H, -CHd
); 6.23 (d, 1H, JH-H ) 6.6 Hz dCH-); 7.22, 7.57 (m, 5H, Ph).
MS (m/z (relative intensity)): 264 (2, M•+), 249 (7), 161 (10),
149 (16), 148 (8), 147 (41), 136 (14), 135 (100), 107 (5), 105 (6),
75 (8), 73 (31).
Acknowledgment. This work supported by Grant
No. 3 T09A 145 26 from the Ministry of Science and
Information Society Technologies of Poland.
Supporting Information Available: A CIF file, giving
crystallographic data for complex IV. This material is available
free of charge via the Internet at http://pubs.acs.org. Crystal-
lographic data (excluding structure factors) for the structural
analysis have also been deposited with the Cambridge Crys-
tallographic Data Centre, No. CCDC-264289. Copies of this
information may be obtained free of charge from The Dir-
ector, CCDC, 12 Union Road, Cambridge, CB2 1EZ, U.K.;
fax +44(1223)336-033; e-mail deposit@ccdc.cam.ac.uk; web
www.ccdc.cam.ac.uk.
Synthesis of [3-(Trimethylsilyl)propionyl]dimethyl-
phenylsilane (4a). A portion of 1a (1.0 g, 2.5 mmol) and 6
mL of acetone were placed in a single-neck flask (10 mL)
equipped with a magnetic stirrer. Then to the mixture obtained
was added 2 mL of 0.4 mol/L hydrochloric acid solution in Et2O.
The reaction was conducted for 4 h at room temperature. After
OM050478H