Baker’s yeast reduction of α-alkyl-α-hydroxy-β-keto esters

Cyclic or acyclic α-alkyl-α-hydroxy-β-keto esters were reduced by baker’s yeast with high stereospecificity. In the former case, one enantiomer of the racemic mixture was transformed into optically active trans-dihydroxy compounds, while the remaining α-hydroxy-β-keto ester was enantiopure.