SELECTIVE FORMATION OF ALKENES FROM TRIMETHYLSILYLMETHYL KETONES AND FROM ACYLSILANES

Trimethylsilylmethyl ketones, readily available from acyl chlorides, undergo a Reformatsky-Peterson reaction sequence to give 3-alkenoates regioselectively. Acylsilanes, however, react with either zinc ester enolates or trimethylsilylmethylmagnesium chloride to give the corresponding tertiary alcohols which, depending on their structure, spontaneously undergo either elimination or a Brook rearrangement-Peterson olefination sequence. These reactions allow the selective formation of vinylsilanes.