Notes - Organosilanes Containing Aralkyl Groups

Highly efficient B(C(6)F(5))(3)-catalyzed hydrosilylation of olefins

A convenient and highly efficient method for the Lewis acid-catalyzed trans-selective hydrosilylation of alkenes has been developed. The mechanism of this novel protocol operates via direct addition of silylium type species across C=C bond followed by trapping of the resultant carbenium ion with boron-bound hydride. A number of diversely substituted silanes possessing both aryl and alkyl groups at silicon atom were efficiently prepared using this hydrosilylation methodology. The possibility to employ aryl-containing hydrosilanes in this reaction opens broad capabilities for the synthesis of alcohols via a trans-selective hydrosilylation/Tamao-Fleming oxidation sequence, complementary to the existing cis-selective hydroboration/oxidation protocol.

SPECTRAL AND CHEMICAL PROPERTIES OF β- AND γ-FUNCTIONAL SILANES

The synthesis of β- and γ-hydroxy- and keto-silanes is described, together with that of their carbon analogues. Unlike the α-isomers, the hydroxysilanes do not rearrange to silyl ethers, and the ultraviolet spectra of the silyl ketones is essentially the same as those of the carbon analogues, and unlike that of α-silyl ketones.β-Silyl ketones have a carbonyl-stretching frequency midway between that of ordinary ketones and α-silyl ketones. These effects are discussed.