The conjugate addition of a silyl group to enones and its removal with copper(II) bromide: a protecting group for the αβ-unsaturation of αβ-unsaturated ketones

Abstract

Silyl-lithium reagents mixed with copper(I) salts react with enones, including esters and aldehydes, to give β-silyl carbonyl compounds in good yield. The β-silylketones can be used in synthesis without risk to the silyl group and the enone group can be restored by bromination-desilylbromination with copper(II) bromide. The principle is illustrated with syntheses of carvone and dihydrojasmone.