The Cyclopropylmethylsilane Terminated Prins Reaction: Stereoelectronic Controlled Formation of (<i>E</i>)-Skipped Dienes Alcohols and a (<i>Z</i>)-Skipped Diene Modification

Abstract

The reaction of 1-phenyldimethylsilyl-2-vinyl cyclopropane with aldehydes under the influence of dimethylaluminium chloride proceeds smoothly to provide skipped diene alcohols with exclusive E-olefin geometry regardless of the initial cis/trans configuration of the starting cyclopropane. The reaction is under stereoelectronic control where the Prins cation favours an anti-bisected conformation. A syn-bisected conformation can be partially induced by the introduction of a buttressing trimethylsilyl group on the cyclopropane ring, leading to competitive (masked) Z-skipped diene formation.