ORGANIC
LETTERS
2007
Vol. 9, No. 20
4073-4076
Highly Efficient O-Silylation of Alcohol
with Vinylsilane Using a Rh(I)/HCl
Catalyst at Room Temperature
Jung-Woo Park and Chul-Ho Jun*
Department of Chemistry and Centre for BioactiVe Molecular Hybrid (CBMH),
Yonsei UniVersity, Seoul 120-749, Korea
Received August 6, 2007
ABSTRACT
Highly efficient O-silylation of alcohol with vinylsilane was developed using a catalyst system consisting of [(COE)2RhCl]2 and HCl. In this
reaction, a key intermediate is chlorosilane, generated from vinylsilane and HCl, which can be regenerated in the catalytic cycle. Various
alcohols and vinylsilanes were applied to the preparation of silyl ether compounds with this catalyst system.
The O-silylation of hydroxyl groups has great potential as a
protecting strategy in organic synthesis.1 A variety of
O-silylation methods for preparing silyl ether compounds
from alcohols have been developed. These methods have
utilized chlorotrialkylsilane,2 hexamethyldisilazane,3 tri-
methylsilyl azide,4 trimethylsilyl cyanide,5 allylsilane,6 silyl
methallylsulfinate,7 etc. In addition, several efficient and
environmentally benign O-silylation processes using transi-
tion-metal catalysts have been reported: dehydrogenative
silylation,8 silylation by disilane,9 allylsilane,6e,f etc. However,
some of these processes have limitations, including the
removal of stoichiometric byproducts,2 the instability of
silane substrates toward moisture,2-5 the requirement of high-
temperature reaction conditions,6,9 and the rarity of various
silane derivatives.3,8,9 Recently, we reported the Rh(I)-
catalyzed O-silylation of alcohol with vinylsilane,10 but this
reaction requires high temperature (>100 °C). However, in
the course of our studies of transition-metal-catalyzed
O-silylation, we discovered a new catalytic system for
O-silylation of alcohol which operates under very mild
conditions. Herein, we wish to report a novel catalyst
mixture, Rh(I) and HCl, for highly efficient O-silylation of
alcohol with vinylsilane at room temperature. This reaction
proceeds well, even in aerial conditions.
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vinylsilane 2a (1.5 mmol) was carried out at ambient
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10.1021/ol701909e CCC: $37.00
© 2007 American Chemical Society
Published on Web 09/08/2007