RETRACTED: Chemoenzymatic Method for Enantioselective Synthesis of (R)-2-Phenylglycine and (R)-2-Phenylglycine Amide from Benzaldehyde and KCN Using Difference of Enzyme Affinity to the Enantiomers (Retracted Article)

In general, enzymatic and chemoenzymatic methods for asymmetric synthesis of alpha-amino acids are performed using highly enantioselective enzymes. The enzymatic reactions using alpha-aminonitrile as a starting material have been performed using reaction conditions apart from the chemical Strecker synthesis. We developed a new chemoenzymatic method for the asymmetric synthesis of alpha-amino acids from aldehydes and KCN by performing Strecker synthesis and nitrilase reaction in the same reaction mixture. Nitrilase AY487533 that showed rather low enantioselectivity in hydrolysis of 2-phenylglycinonitrile (2PGN) to 2-phenylglycine (2PG) was utilized in the hydrolysis of aminonitrile formed from benzaldehyde and KCN via 2PGN by Strecker synthesis, preferentially synthesizing (R)-2PG with more than 95 % yield and enantiomeric excess (ee). The method was also utilized for the synthesis of (R)-2-phenylglycine amide ((R)-2PGNH(2)) from benzaldehyde and KCN by the chemoenzymatic reaction in the presence of a mutated nitrilase AY487533W186A, which catalyzes the conversion of 2PGN to 2PGNH(2).