Reduction of β-Keto Esters with a Reductase: Construction of Plural Stereocenters Remote from the Reaction Center

The reduction ofsec-alkyl 2-methyl-3-oxobutyrate with a keto ester reductase from bakersʹ yeast (YKER-I) is accompanied by simultaneous dynamic and static resolution of chiral centers affording the corresponding (2R,3S,1′R)-hydroxy esters preferentially. Thus, the enzyme discriminates three chiral centers simultaneously in high stereoselectivity producing useful chiral building blocks. To study the effect of the alcohol moiety which is located at a remote position from the reaction center, upon the interaction between the enzyme and a substrate, steady-state kinetic parameters,Kmandkcat, of YKER-I for each (1′R)- and (1′S)-substrate have been determined. The results reveal that the stereochemistry at the alcohol moiety affectsKmrather thankcat.