The catalytic activity of alkali metal alkoxides and titanium alkoxides in the hydrosilylation of unfunctionalized olefins

Article abstract of DOI:10.1080/10426507.2018.1493480

The catalytic activities of titanium alkoxides and alkali metal alkoxides for hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV) alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low catalytic activity for the hydrosilylation of olefins. However, by using titanocene dichloride as an additive, alkali metal alkoxides showed also excellent catalytic property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was obtained by using alkali metal alkoxides/Cp₂TiCl₂ as catalysts.

Full text of DOI:10.1080/10426507.2018.1493480

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: http://www.tandfonline.com/loi/gpss20
The catalytic activity of alkali metal alkoxides
and titanium alkoxides in the hydrosilylation of
unfunctionalized olefins
Xiaoling Yang, Ying Bai, Jiayun Li, Yu Liu, Jiajian Peng, Tianbo Li, Rui Lang &
Botao Qiao
To cite this article: Xiaoling Yang, Ying Bai, Jiayun Li, Yu Liu, Jiajian Peng, Tianbo Li, Rui Lang
&
Botao Qiao (2018): The catalytic activity of alkali metal alkoxides and titanium alkoxides in
the hydrosilylation of unfunctionalized olefins, Phosphorus, Sulfur, and Silicon and the Related
Elements, DOI: 10.1080/10426507.2018.1493480
To link to this article: https://doi.org/10.1080/10426507.2018.1493480
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The catalytic activity of alkali metal alkoxides and titanium alkoxides
in the hydrosilylation of unfunctionalized olefins
a
a
a
a
a
Xiaoling Yang , Ying Bai *, Jiayun Li , Yu Liu , Jiajian Peng *, Tianbo
b
b
b
Li , Rui Lang and Botao Qiao
a
Key Laboratory of Organosilicon Chemistry and Material Technology of
Ministry of Education, Hangzhou Normal University, Hangzhou 311121,
China
b
Dalian Institute of Chemical Physics, Chinese Academy of Sciences,
Dalian 116011, China
∗
E-mail: ybai@hznu.edu.cn (Y. Bai), jjpeng@hznu.edu.cn (J.J. Peng)
Abstract The catalytic activities of titanium alkoxides and alkali metal alkoxides for
hydrosilylation of unfunctionalized olefins have been studied. Titanium(IV)
alkoxides showed excellent catalytic activity, while alkali metal alkoxides have low
catalytic activity for the hydrosilylation of olefins. However, by using titanocene
dichloride as an additive, alkali metal alkoxides showed also excellent catalytic
property for hydrosilylation. In comparison with titanium alkoxides, no α-adduct was
obtained by using alkali metal alkoxides/Cp TiCl as catalysts.
2
2
SiHPh2
SiHPh2
R
+
R
titanium alkoxide
and/or alkali metal alkoxide
1
2
+
Ph SiH2
2
R
+
R
R = C H , C H , C H
6 5
4
9
6
13
3

Keywords Hydrosilylation; Titanium alkoxide; Alkali metal alkoxide; Olefin
1
. Introduction
Silicon-containing organic compounds and organosilicon polymers are of
significant interest for their chemical, electronic, optical as well as physical properties
1]. The hydrosilylation of unsaturated bond, e.g. C=C, C=O, C≡C is an efficient
[
method for preparing organosilicon compounds and polymers. The catalytic
hydrosilylation of the carbon-carbon double bond has been widely studied and applied,
and the hydrosilylation of the carbon carbon double bond was effectively promoted by
transition metals including platinum and rhodium complexes [2,3]. However, the high
cost of these noble metal complexes was the main drawback for their application in
industrial processes [4,5]. Hence, an ongoing challenge is the development of
low-cost metal catalyst system. Recently, the hydrosilylation of alkenes catalyzed
with iron[6-8], cobalt[9-12] and nickel complexes [13] have been reported. Harder et
al reported the first hydrosilylation catalysts based on alkaline-earth metals (Ca, Sr
and Ba) [14]. The group IV transition metal complexes used as hydrosilylation
catalysts had also been reported. Both dehydrogenative coupling of hydrosilanes and
hydrosilylation reaction could be conducted in the presence of Cp Ti(OPh) [15].
2
2
1
,4-Hydrosilylation of dienes can be carried out in the presence of Cp TiF [16].
2 2
Silyltitanocene complexes [17] and metallocene-type Ti(III) complexes [18] were
reported to catalyze the hydrosilylation reaction under mild conditions and the results
of Cp MCl /nBuLi as a catalyst, have also been reported [19]. Considerable efforts
2
2
are being made to develop the application group IV metal complexes as catalysts, and
titanium alkoxides have been considered as Lewis acids for catalytic reactions and
i
polymerizations [20-23]. Buchwald et al [24] reported that Ti(O Pr) could efficiently
4
catalyze the hydrosilylation of carboxylic esters. Tertiary phosphine oxides could be
reduced using hydrosiloxanes in the presence of a catalytic amount of titanium
alkoxides [25-28].
In comparison to titanium alkoxides as a Lewis acid, alkali metal alkoxides are

always used as organic bases as well as catalysts for catalytic reactions, e.g. transfer
hydrogenation of ketones [29], hydrosilylation of ketones [30] and tertiary amides
[
31], Claisen-Tishchenko reaction [32] and hetero-Aldol-Tishchenko reaction [33].
Herein, we describe our investigation into the use of titanium alkoxides and/or alkali
metal alkoxides as catalysts for the hydrosilylation of olefins (Scheme 1).
[
Insert Scheme 1]
2
. Results and discussion
Initially, the hydrosilylation of olefins in the presence of different titanium
alkoxides was investigated (Table 1). The results indicated that Ti(OEt) exhibits the
4
n
i
highest catalytic activity among Ti(OEt) , Ti(O Bu) and Ti(O Pr) , and α-adduct,
4
4
4
β-adduct and hydrogenation product were detected, while no dehydrosilylation
product 4 was detected (Entries 1-4, Table 1). Other hydrosilanes such as (EtO) SiH
3
and alkenes such as 1-octene and 1-dodecene were also examined under the same
conditions (Entries 5-7, Table 1). While the polymerization of styrene was detected
(
Entry 8, Table 1), no reaction could be conducted by using cyclohexene nor Et SiH as
3
one of the substrates.
[
Insert Table 1]
Secondly, we examined the hydrosilylation of olefins catalyzed with alkali metal
alkoxides and/or additives (Table 2). Lower conversion of 1-octene with high
t
t
selectivity of β-adduct was obtained by using LiO Bu or KO Bu as catalyst (Entries 1-2,
t
Table 2). Slightly enhanced catalytic activity of KO Bu was observed in the presence
of 1 mol% benzo-18-crown-6 (Entry 3, Table 2). Titanocene dichloride exhibits no
catalytic activity for the hydrosilylation under the same conditions (Entry 4, Table 2).
Titanocene dichloride can effectively improve the catalytic activity of alkali metal
alkoxides (Entries 5-11, Table 2). When the amount of titanocene dichloride was
increased from 1% to 3%, the conversion of 1-octene increased from 96.3% to 98.3%
(Entries 5-7, Table 2). The catalytic activity of titanium alkoxides for hydrosilylation
of 1-octene was determined in the initially experiments (Table 1) and furthermore, we

examined the catalytic activity of alkali metal alkoxide combined with titanium
alkoxide. However, depress of activity was observed when the mixture of two kinds
of metal alkoxides was used as catalyst (Entries 12-14, Table 2). The formation of
MTi(OR) (M=Li, Na, K) or their dimeric complexes by reaction of alkali metal
5
alkoxides with titanium alkoxides had been reported [34], which resulted in a reduced
activity. Additionally, in comparison with titanium alkoxides, no α-adduct was
obtained by using alkali metal alkoxides alone and alkali metal alkoxides/Cp TiCl as
2
2
catalysts.
Insert Table 2]
[
t
Using LiO Bu/Cp TiCl as catalyst, the influence of reaction temperature on the
2
2
catalytic hydrosilylation of 1-octene with diphenylsilane was investigated (Table 3).
The results indicated that activity increased along with the temperature raising from
room temperature to 100 ℃.
[
Insert Table 3]
To speculate the mechanism of catalytic reaction, Shimada et al [18]
demonstrated that silyltitanium (III) complex was the intermediate, therefore, the
possible reaction path for hydrosilylation of olefin catalyzed with titanium alkoxides
was proposed in Scheme 2. On the other hand, Okuda [35] reported that the
alkali-metal silyl catalyzed the hydrosilylation of activated carbon carbon double
bond and a silyl migration mechanism is operative. Thus, the mechanism of alkali
metal alkoxides catalyzed hydrosilylation is proposed in Scheme 3.
[
[
Insert Scheme 2]
Insert Scheme 3]
2
9
To investigate the reaction mechanism, the Si NMR of the reaction mixture
t
(
Cp TiCl +LiO Bu+Ph SiH at 90℃ for 2h) were measured. Ph SiH (δ-18.85 ppm),
2
2
2
2
3

Ph SiH (δ-33.03 ppm), (Ph SiH) (δ-34.73 ppm) and Cp Ti(III)SiHPh (δ-23.42
2
2
2
2
2
ppm)[36] were determined. Thus the silyltitanium (III) complex as the intermediate
29
was demonstrated. The Si NMR of the reaction mixture [Ti(OEt) + Ph SiH at 90℃
4
2
2
for 2h] was also measured; the peak of δ-45.98～-45.83ppm should be attributed to
Ti(III) (OEt) SiHPh , thus the low value titanium species should the intermediate.
2
2
(Figures S 1 and S 2, Supplemental Materials ).
3
. Conclusion
In summary, the catalytic activities of titanium alkoxides for hydrosilylation of
olefins has been studied. Titanium(IV) ethoxide showed the highest catalytic activity
among the titanium alkoxides tested. The hydrosilylation of olefins catalyzed with
alkali metal alkoxides and/or additives had also been investigated. By using
titanocene dichloride as additive, alkali metal alkoxides showed excellent catalytic
properties for hydrosilylation.
Experimental section
4
.1 General information
t
t
t
i
n
Cp TiCl , LiO Bu, NaO Bu, KO Bu, Ti(OEt) , Ti(O Pr) , Ti(O Bu) , cyclohexene,
2
2
4
4
4
styrene, 1-octene, 1-hexene, 1-dodecene, diphenylsilane, (EtO) SiH and other
3
reagents were commercially available and were used without further purification.
1
13
29
H, C and Si spectra were measured using a Bruker AV400 MHz
spectrometer operating at 400.1, 100.6 and 79.5MHz, respectively. GC-MS analysis
on an Agilent 7890B-5977B apparatus equipped with a HP-5MS column (30 m × 0.25
mm × 0.25μm). Gas Chromatography: Trace DSQ GC Column = DB-5 30 m×2.5
-1
mm×0.25 μm, split = 50:1, flow = 1 mL min constant flow, inlet temperature = 260
-1
ºC, column temperature = 50 ºC (hold 1 min) then 15 ºC min up to 260 ºC (hold 10
min).

4
.2 General procedure for the catalytic hydrosilylation of olefins
The calculated amount of catalyst was charged into a 10 mL round-bottomed
flask equipped with magnetic stirring under nitrogen, and then olefin (4.0 mmol) and
hydrosilane (4.4 mmol) were added into the flask. The resulting mixture was stirred at
the desired reaction temperature for the desired time. At the end of the reaction, the
reaction mixture was analyzed by GC/MS, and the conversion of alkene as well as the
selectivity of products were determined by GC.
Acknowledgments
This work was supported by Natural Science Foundation of Zhejiang Province
(
LY18B020012) and Zhejiang Provincial Technologies R&D Program of China
grant no. 2017C31105).
(
References
[
[
[
1] Nakajima, Y. and Shimada, S. Hydrosilylation reaction of olefins: recent advances
and perspectives, RSC Adv. 2015, 5, 20603-20616
2] Du, X.; Huang, Z. Advances in Base-Metal-Catalyzed Alkene Hydrosilylation,
ACS Catal. 2017, 7, 1227-1243
3] Peng, J.J.; Bai, Y.; Li, J.Y.; Lai，G.Q. Recent Progress in Transition Metal
Complexes Catalyzed Hydrosilylation of Carbon-Carbon Multiple Bonds, Current
Org. Chem. 2011, 15, 2802-2815
[
4] Hofmann, R.J.; Vlatković, M.; Wiesbrock, F. Fifty Years of Hydrosilylation in
Polymer Science: A Review of Current Trends of Low-Cost Transition-Metal and
Metal-Free Catalysts, Non-Thermally Triggered Hydrosilylation Reactions, and
Industrial Applications, Polymer 2017, 9, 534-571
[
[
5] Zaranek, M.; Marciniec, B.; Pawluć, P. Ruthenium-catalysed hydrosilylation of
carbon–carbon multiple bonds, Org. Chem. Front. 2016, 3, 1337-1344
6] Tondreau, A.M.; Altienza, C.C.H.; Weller, K.J.; Nye, S.A.; Lewis, K.M.; Delis,

J.G.P; Chirik, P.J. Iron Catalysts for Selective Anti-Markovnikov Alkene
Hydrosilylation Using Tertiary Silanes, Science 2012, 335, 567-570
[
[
7] Noda, D.; Tahara, A.; Sunada, Y. and Nagashima, H. Non-Precious-Metal
Catalytic Systems Involving Iron or Cobalt Carboxylates and Alkyl Isocyanides
for Hydrosilylation of Alkenes with Hydrosiloxanes, J. Am. Chem. Soc. 2016, 138,
2
480-2483
8] Greenhalgh, M.D.; Frank, D.J.; Thomas, S.P. Iron-Catalysed Chemo-, Regio-, and
Stereoselective Hydrosilylation of Alkenes and Alkynes using a Bench-Stable Iron
(
II) Pre-Catalyst, Adv. Synth. Catal. 2014, 356, 584-590
[
[
9] Sun, J.; Deng, L. Cobalt complex-catalyzed hydrosilylation of alkenes and alkynes,
ACS Catal. 2016, 6, 290-300
10] Chen, C.; Hecht, M.B.; Kavara, A.; Brennessel, W.W.; Mercado, B.Q.; Weix,
D.J. and Holland, P.L. Rapid, regioconvergent, solvent-free alkene hydrosilylation
with a cobalt catalyst, J. Am. Chem. Soc. 2015, 137, 13244-13247
[
[
[
[
11] Liu, Y.; Deng, L.Mode of activation of cobalt (ii) amides for catalytic
hydrosilylation of alkenes with tertiary silanes, J. Am. Chem. Soc. 2017, 139,
1
798-1801
12] Cheng, B.; Lu, P.; Zhang, H.; Cheng, X.; Lu, Z. Highly enantioselective
cobalt-catalyzed hydrosilylation of alkenes, J. Am. Chem. Soc. 2017, 139,
9
439-9442
13] Pappas, I.; Treacy, S.; Chirik, P.J. Alkene hydrosilylation using tertiary silanes
with α-diimine nickel catalysts. redox-active ligands promote a distinct
mechanistic pathway from platinum catalysts, ACS Catal. 2016, 6, 4105-4109
14] Buch, F.; Brettar, J.; Harder, S. Hydrosilylation of Alkenes with Early
Main-Group Metal Catalysts, Angew. Chem. 2006, 118, 2807-2811
[
15] Garcia, J.; Meyer, D.J.M.; Guillaneux, D.; Moreau, J.J.E.; Man, M.W.C.
Investigation of titanium-catalysed dehydrogenative coupling and
hydrosilylation of phenylhydrogenosilanes in a one-pot process, J. Organomet.
Chem. 2009, 694, 2427-2433
[
16] Bareille, L.; Becht, S.; Cui, J.L.; Gendre, P.L.; Moïse, C. First

Titanium-Catalyzed anti-1,4-Hydrosilylation of Dienes, Organometallics 2005,
4, 5802-5806
2
[
[
17] Harrod, J.F.; Yun, S.S. Silyltitanocene complexes as catalysts for the
hydrogenation, isomerization, and hydrosilylation of olefins, Organometallics
1
987, 6, 1381-1387
18] Eguchi, K.; Aoyagi, K.; Nakajima, Y.; Ando, W.; Sato, K.; Shimada, S.
Synthesis and Structure of Metallocene-type Ti(III) Complexes, and Their
Catalytic Activity towards Olefin Hydrosilylation Reactions, Chem. Lett. 2017, 46,
1
262-1264
[
[
19] Corey, J.Y.; Zhu, X.H. Reactions of hydrosilanes and olefins in the presence of
Cp MCl /nBuLi, Organometallics 1992, 11, 672-683
2
2
20] Bull, S.D.; Davidson, M.G.; Johnson, A.L.; Robinson, D.E.J.E.; Mahon, M. F.
Synthesis, structure and catalytic activity of an air-stable titanium triflate,
supported by an amine tris (phenolate) ligand, Chem. Commun. 2003, 1750-1751
21] Bull, S.D.; Davidson, M.G.; Johnson, A.L.; Mahon, M.F.; Robinson, D.E.J.E. An
Air Stable Moisture Resistant Titanium Triflate Complex as a Lewis Acid
Catalyst for C- C Bond Forming Reactions, Chem. Asian J. 2010, 5, 612-620
22] Chmura, A.J.; Davidson, M.G.; Jones, M.D.; Lunn, M.D.; Mahon, M.F. Group 4
complexes of amine bis (phenolate) s and their application for the ring opening
polymerisation of cyclic esters, Dalton Trans. 2006, 887-889
[
[
[
[
[
23] Sernetz, F.G.; Mülhaupt, R.; Fokken, S.; Okuda, J. Copolymerization of ethene
with styrene using methylaluminoxane-activated bis (phenolate) complexes,
Macromolecules 1997, 30, 1562-1569
24] Reding, M.T.; Buchwald, S.L. An inexpensive air-stable titanium-based system
for the conversion of esters to primary alcohols, J. Org. Chem. 1995, 60,
7
884-7890
25] Petit, C.; Favre-Reguillon, A.; Albela, B.; Bonneviot, L.; Magnani, G.;
Lemaire, M. Mechanistic Insight into the Reduction of Tertiary Phosphine
i
Oxides by Ti(O Pr) /TMDS, Organometallics 2009, 28, 6379-6382
4

[
[
26] Verdaguer, X.; Lange, U.E.W.; Buchwald, S. L. Amine additives greatly expand
the scope of asymmetric hydrosilylation of imines, Angew. Chem. Int. Ed. 1998,
3
7, 1103-1107
27] Asburn, B.O.; Carter, R.G. Diels–Alder Approach to Polysubstituted Biaryls:
Rapid Entry to Tri- and Tetra-ortho-substituted Phosphorus-Containing Biaryls,
Angew. Chem. Int. Ed. 2006, 45, 6737-6741
[
28] Vinokurov, N.; Pietrusiewicz, K.M.; Frynas, S.; Wiebcke, M.; Butenschön, H.
Asymmetric 1, 3-dipolar cycloaddition with a P-stereogenic dipolarophile: An
efficient approach to novel P-stereogenic 1, 2-diphosphine systems, Chem.
Commun. 2008, 5408-5410
[
[
29] Ekström, J.; Wettergren, J.; Adolfsson, H. A simple and efficient catalytic
method for the reduction of ketones, Adv. Synth. Catal. 2007, 349, 1609-1613
30] Xiang, Q.Y.; Li, J.Y.; Peng, J.J.; Bai, Y.; Hu, Y.Q.; Lai, G.Q. Catalytic
hydrosilylation of ketones using KOBu-t, Acta Chimica Sinica 2010, 68,
3
63-368
[
[
[
[
31] Ding, G.; Wu, X.; Jiang, L.; Zhang, Z.; Xie, X. Reduction of Benzolactams to
Isoindoles via an Alkoxide-Catalyzed Hydrosilylation, Org. Lett. 2017, 19,
6
048-6051
32] Rajesh, K.; Berke, H. Alkali Metal tert-Butoxides, Hydrides and Bis
trimethylsilyl) amides as Efficient Homogeneous Catalysts for Claisen–
(
Tishchenko Reaction, Adv. Synth. Catal. 2013, 355, 901-906
33] Mascarenhas, C.M.; Duffey, M.O.; Liu, S.-Y.; Morken, J.P. Simple Metal
Alkoxides as Effective Catalysts for the Hetero-Aldol− Tishchenko Reaction,
Org. Lett. 1999, 1, 1427-1429
34] Boyle, T.J.; Alam, T.M.; Tafoya, C.J.; Mechenbier, E.R. Syntheses,
characterizations, and X-ray structures of alkali metal derivatives of titanium (IV)
neopentoxides, Inorg. Chem. 1999, 38, 2422-2428

[
[
35] Leich, V.; Spaniol, T.P.; Okuda, J. Potassium-Catalyzed Hydrosilylation of
Activated Olefins: Evidence for a Silyl Migration Mechanism, Organometallics
2
016, 35, 1179-1182
36] Gruber-Woelfler H.; Khinast J.G. Titanocene-Catalyzed Hydrosilylation of
Imines: Experimental and Computational Investigations of the Catalytically
Active Species, Organometallics 2009, 28, 2546–2553

Table 1 Hydrosilylation of olefins catalyzed with titanium alkoxides
Select.(%)
Ti(OR) /mo
Conv
(%)
4
Entry
Olefin
Silane
l%
1
2
3
1
2
3
4
Ti(OEt) /3
1-octene
1-octene
1-octene
1-octene
Ph SiH
85.7
86.0
10.7
3.3
1.4
2.2
2.9
4
2
2
2
2
2
b
Ti(OEt) /5
Ph SiH
98.7 85.4(78.8)
13.2
29.2
43.9
4
2
n
Ti(O Bu) /5
Ph SiH
93.3
97.3
68.6
53.2
4
2
i
Ti(O Pr) /5
Ph SiH
4
2
(
EtO) Si
3
5
Ti(OEt) /5
1-octene
58.1
81.4
/
18.6
4
H
6
7
Ti(OEt) /5
1-hexene
1-dodecene
styrene
Ph SiH
99.5
75.6
22.9
1.5
4
2
2
2
2
2
Ti(OEt) /5
Ph SiH
96.1
67.6
28.3
4.1
4
2
a
8
Ti(OEt) /5
Ph SiH
/
/
/
/
/
/
/
/
/
/
/
/
4
2
9
Ti(OEt) /5 cyclohexene Ph SiH
4
2
10
Ti(OEt) /5
1-octene
Et SiH
3
4
a
Polymerization of styrene was determined
isolated yield in bracket
b
Reaction conditions: olefin 4.0 mmol，hydrosilane 4.4 mmol，90ºC, 12h

Table 2 Alkali metal alkoxides and/or additive catalyzed hydrosilylation of 1-octene
Alkali
metal
Select.(%)
Conv.
(%)
Entry
Additive/mol%
alkoxide/
mol%
1
2
3
t
1
2
3
4
5
6
7
8
9
LiO Bu/5
/
/
17.0
15.2
28.6
/
100
100
100
/
/
/
t
KO Bu/5
/
/
t
KO Bu/5 Benzo-18-crown-6/1
/
/
/
Cp TiCl /3
/
/
2
2
t
LiO Bu/5
Cp TiCl /1
96.3
96.8
98.3
80.6
67.5
99.3
97.4
30.4
/
84.4
84.9
87.3
86.5
87.1
85.4
86.3
100
/
/
15.6
15.1
12.7
13.5
12.9
14.6
13.7
/
2
2
t
LiO Bu/5
Cp TiCl /2
/
2
2
t
LiO Bu/5
Cp TiCl /3
/
2
2
t
LiO Bu/4
Cp TiCl /3
/
2
2
t
LiO Bu/3
Cp TiCl /3
/
2
2
t
1
1
1
1
1
0
1
2
3
4
NaO Bu/5
Cp TiCl /3
/
2
2
t
KO Bu/5
Cp TiCl /3
/
2
2
t
LiO Bu/5
Ti(OEt) /0.5
/
/
4
t
LiO Bu/5
Ti(OEt) /1
/
4
t
LiO Bu/1
Ti(OEt) /5
71.9
86.4
7.5
6.1
4
Reaction conditions: 1-octene 4.0 mmol，Ph SiH 4.4 mmol，90℃，6h.
2
2

t
Table 3 Influence of reaction temperature on LiO Bu/Cp TiCl catalyzed
2
2
hydrosilylation
Select.(%)
Conv.
Entry Temp （. ℃）
(
%)
1
/
2
/
3
1
2
3
4
5
6
r.t.
50
/
/
73.7
93.9
94.0
98.2
98.3
84.5
/
15.5
13.6
15.2
12.6
12.3
70
86.4
/
80
84.8
/
a
90
87.4 (79.6)
/
100
87.7
/
a
isolated yield in bracket
t
Reaction conditions: 1-octene 4.0 mmol，Ph SiH 4.4 mmol，Cp TiCl 3 mol %，LiO Bu
2
2
2
2
5
mol %, 6h.

SiHPh2
SiHPh2
R
+
R
titanium alkoxide
1
2
+
Ph SiH2
2
R
and/or alkali metal alkoxide
+
R
R = C H , C H , C H
6 5
4
9
6
13
3
Scheme 1 Hydrosilylation of olefins catalyzed with titanium alkoxides and /or alkali metal alkoxides
Ti(OR)4
Ph SiH2
2
ROH
C H
6
13
(
3
RO) TiSiHPh2
C H17SiHPh2
8
SiHPh2
Ph SiH2
2
(RO) Ti
3
C H
6
13
Scheme 2 Titanium alkoxide catalyzed
hydrosilylation
MOR
Ph SiH2
2
ROH
C H
6 13
MSiHPh2
C H17SiHPh2
8
M= Li, Na, K
SiHPh2
Ph SiH2
M
2
C H
6
13
Scheme 3 Alkali metal alkoxide catalyzed
hydrosilylation