Introduction
<P>Phenylsilane (PhSiH
3) is an organosilane and has been
extensively used in organic synthesis as a mild and environmentally
benign reducing agent. It is a clear, colorless, volatile liquid
which boils at 120 ˚C.
[
¹]
When
heated to decomposition it emits acrid smoke and irritating vapors.
It reacts violently with water, so the preparation of phenylsilane
must be performed in a reaction vessel connected with a vacuum system
by a standard ground glass joint. It has been used for the hydrosilylation
reduction of ketones and aldehydes to give the corresponding alcohols.
[
²]
It was also found to be
an efficient reagent for selective reduction of quinoline to dihydroquinoline,
[
³]
reductive Michael cyclization,
[
4]
and reductive aldol reaction.
[
5]
The reductive coupling of aldimines
has been achieved by the use of a combination of PhSiH
3 and
titanium isopropoxide [Ti(O
i-Pr)
4].
[
6]
Reductions of organic halides to
dehalogenated alkanes with the In(OAc)
3-PhSiH
3 system
are readily accomplished.
[
7]
It can
also act as an in situ carboxylic acid activating agent to prepare
carboxamides and peptides from carboxylic acids and amines.
[
8]
</P><P>Phenylsilane is commercially available now. It can be readily
prepared by reduction of phenyltrichlorosilane with lithium aluminum
hydride in ether.
[
9]
</P>
Scheme 1
