Stoichiometric and Catalytic Activation of Si−H Bonds
by a Triruthenium Carbonyl Cluster,
(μ<sub>3</sub>,η<sup>2</sup>:η<sup>3</sup>:η<sup>5</sup>-acenaphthylene)Ru<sub>3</sub>(CO)<sub>7</sub>: Isolation of the
Oxidative Adducts, Catalytic Hydrosilylation of
Aldehydes, Ketones, and Acetals, and Catalytic
Polymerization of Cyclic Ethers
Hideo Nagashima
Akihiro Suzuki
Takafumi Iura
Kazuhiro Ryu
Kouki Matsubara
10.1021/om0003887.s001
https://acs.figshare.com/articles/journal_contribution/Stoichiometric_and_Catalytic_Activation_of_Si_H_Bonds_by_a_Triruthenium_Carbonyl_Cluster_sub_3_sub_sup_2_sup_sup_3_sup_sup_5_sup_-acenaphthylene_Ru_sub_3_sub_CO_sub_7_sub_Isolation_of_the_Oxidative_Adducts_Catalytic_Hydrosilylation_of_Aldehydes_Ketones_an/3762990
Treatment of the ruthenium cluster (μ<sub>3</sub>,η<sup>2</sup>:η<sup>3</sup>:η<sup>5</sup>-acenaphthylene)Ru<sub>3</sub>(CO)<sub>7</sub> (<b>1</b>) with stoichiometric amounts of trialkylsilanes results in liberation of a CO ligand followed by
oxidative addition of a Si−H bond. The trinuclear silyl complexes (μ<sub>3</sub>,η<sup>2</sup>:η<sup>3</sup>:η<sup>5</sup>-acenaphthylene)Ru<sub>3</sub>(H)(SiR<sub>3</sub>)(CO)<sub>6</sub> (<b>2</b>) were isolated in good yield. They were characterized by NMR
spectroscopy and X-ray crystallography. Compound <b>1 </b>catalyzes the hydrosilylation of olefins,
acetylenes, ketones, and aldehydes. In particular, the reactions of aldehydes and ketones
proceed at room temperature to form the corresponding silyl ethers in good yield; the catalytic
activities are superior to those with RhCl(PPh<sub>3</sub>)<sub>3</sub>. The RhCl(PPh<sub>3</sub>)<sub>3</sub>-catalyzed hydrosilylation
of ketones with Me<sub>2</sub>(H)SiCH<sub>2</sub>CH<sub>2</sub>Si(H)Me<sub>2</sub> results in selective reaction of only one Si−H
terminus, while similar reactions, when catalyzed by <b>1</b>, allow utilization of both Si−H groups.
Significantly different regio- and stereoselectivities, compared with those obtained in
reactions catalyzed by RhCl(PPh<sub>3</sub>)<sub>3</sub>, also were observed in the hydrosilylation of α,β-unsaturated carbonyl compounds and 4-<i>tert</i>-butylcyclohexanone, respectively. The reactions
with acetals and cyclic ethers also take place under similar conditions. The reaction of
trialkylsilanes with an excess of a cyclic ether resulted in ring-opening polymerization.
Polymerization of THF was investigated as a representative example. Treatment of
trialkylsilanes with an excess of THF (10−10<sup>2</sup> equiv with respect to silanes) in the presence
of a catalytic amount of <b>1</b> resulted in production of polytetrahydrofuran with <i>M</i><sub>n</sub> = 1000−200 000 and <i>M</i><sub>w</sub>/<i>M</i><sub>n</sub> = 1.3−2.0. Changing the ratio of THF to HSiR<sub>3</sub> can control the molecular
weight. NMR studies suggested that the structure of the polymer is R<sub>3</sub>SiO−[(CH<sub>2</sub>)<sub>4</sub>O]<i><sub>n</sub></i>−CH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>3</sub>. Mechanistic considerations based on differences in the catalytic activities
between the catalysts <b>1</b> and <b>2</b> are discussed.
2000-08-05 00:00:00
Oxidative Adducts
CO ligand
cyclic ether
trialkylsilanes results
NMR studies
THF
representative example
4 O
Mechanistic considerations
Catalytic Polymerization
Catalytic Activation
catalysts 1
cyclic ethers
silyl ethers
Cyclic Ethers Treatment
Triruthenium Carbonyl Cluster
M n
CH
RhCl
ketone
oxidative addition
stoichiometric amounts
Catalytic Hydrosilylation
acenaphthylene
hydrosilylation
Compound 1 catalyzes
NMR spectroscopy
HSiR 3
carbonyl compounds
room temperature