Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Baker's yeast mediated reduction of α-azido-β-keto ester lead to reduction of the carbonyl group with high enantiospecificity and diastereoselectivity at low pH (4.0, ee >99%, de 79%). At pH ∼7, although the enantioselectivity is maintained, the diastereoselectivity is lost.