THE REACTION OF O-SILYLATED ALPHA-KETOLS WITH TRIMETHYLSILYL CYANIDE

The reactions of a series of O-silylated α-ketols with trimethylsilyl cyanide have been investigated. Formation of the expected O-trimethylsilyl cyanohydrins as major products has been shown to be accompanied by the hitherto unsuspected formation of a disiloxane by a proposed intramolecular SN2 displacement mechanism. The latter reaction is, surprisingly, independent of the substitution pattern in the silylated ketol. Formation of the side-product, however, increases in all cases with increasing dilution. The α,β-epoxynitrile 9, a second side-product expected, along with the observed disiloxane, by our proposed mechanism was synthesized by an unambiguous route. A control experiment showed the epoxynitrile to be completely destroyed under the usual conditions of reaction with trimethylsilyl cyanide. 13C NMR data have been obtained for most of the compounds in this study. © 1991, Taylor & Francis Group, LLC. All rights reserved.