Phenylsilane


Phenylsilane, also known as silylbenzene, a colorless liquid, is one of the simplest organosilanes with the formula C6H5SiH3. It is structurally related to toluene, with a silyl group replacing the methyl group. Both of these compounds have similar densities and boiling points due to these similarities. Phenylsilane is soluble in organic solvents.

Synthesis and reactions

Phenylsilane is produced in two steps from Si4. In the first step, phenylmagnesium bromide is added to form Ph-Si3 via a Grignard reaction. Reduction of the resulting Ph-Si3 product with LiAlH4 affords phenylsilane.

Uses

Phenylsilane can be used to reduce tertiary phosphine oxides to the corresponding tertiary phosphine.
The use of phenylsilane proceeds with retention of configuration at the phosphine. For example, cyclic chiral tertiary phosphine oxides can be reduced to cyclic tertiary phosphines.
Phenylsilane can also be combined with cesium fluoride. In aprotic solvents, it becomes a nonnucleophilic hydride donor. Specifically, phenylsilane-caesium fluoride has been shown to reduce 4-oxazolium salts to 4-oxazolines. This reduction gives yields of 95%.