Debromination of α,α′-dibromo-ketones with a zinc–copper couple in methanol. Formation of α-methoxy-ketones as a criterion for the intervention of 2-oxyallyl cations

Abstract

Debromination of α,α′-dibromo-ketones with a zinc–copper couple in a methanol yields parent ketone and α-methoxy-ketone in varying amounts; the latter, which is formed in an orientationally specific manner, is suggested to arise via a selective 2-oxyallyl cation which is produced in an S_N1 reaction.