Nitrile Biotransformations for Highly Enantioselective Synthesis of Oxiranecarboxamides with Tertiary and Quaternary Stereocenters; Efficient Chemoenzymatic Approaches to Enantiopure α-Methylated Serine and Isoserine Derivatives
2-methyl-3-(para-substituted-phenyl)oxiranecarboxamides. Under very mild conditions, biotransformations of nitriles provided an efficient and practical synthesis of 2R,3S-(−)-3-aryl-2-methyloxiranecarboxamides, electrophilic epoxides with tertiary and quaternary stereocenters, in excellent yield with enantiomeric excess greater than 99.5%. The synthetic applications of the resulting enantiomerically pure