Enantioselective deprotonation of protected 4-hydroxycyclohexanones

Abstract

A series of derivatives of 4-hydroxycyclohexanone (1a–g) with the hydroxy group protected as a silyl ether (1a, b), ether (1d, g), an acetal (1c), or an ester (1e, f) were deprotonated with chiral, optically pure, lithium amides 3–9. The resulting non-racemic enolates were trapped as enol acetates. The enantioselectivity of deprotonation was up to 74% ee.