Stereoselective Reduction of α-Methyl-β-hydroxy Ketones with Zinc Borohydride

Abstract

Zinc borohydride reduction of α-methyl-β-hydroxy ketones 3 produced the erythro-2-methyl-1, 3-glycol derivatives 4 with high stereoselectivity. The selectivity was particularly high when an olefinic group was conjugated to the carbonyl group. Reduction of the same system with NaBH₄ and LiBH₄ showed poor selectivity.