Asymmetric reduction with baker's yeast.

Abstract

The baker's yeast mediated reduction of ketones with various kinds of functional groups provides a useful method for the synthesis of optically active secondary alcohols. Compared with the usual chemical methods using chiral metal hydride reagents, the advantages of the present method are the easier availability of the yeast, milder reaction conditions, i. e. at room temperature in water under air atmosphere, higher optical yield and chemoselectivity especially in the reduction of saturated ketones. Asymmetric reduction of carbon-carbon double bond and the carbon-carbon bond forming reaction of α, β-unsaturated carbonyl compounds are also accomplished by baker' s yeast. The products thus obtained are applied as chiral building blocks to the synthesis of various natural products.