Enzymatic catalysis in organic synthesis. Synthesis of enantiomerically pure C alpha-substituted alpha-amino and alpha-hydroxy acids

Enzymes are versatile catalysts in asymmetric synthesis. We have developed synthetic methodologies for the synthesis and resolution of alpha-amino amides (both alpha-H and alpha,alpha-disubstituted) using preparations of Pseudomonas putida, Mycobacterium neoaurum and Ochrobactrum anthropi with amidase and aminopeptidase activity. Also, highly substituted alpha,alpha-disubstituted amino acids and hydroxy acids can be obtained in enantiomerically pure form using pig liver esterase. In addition, an elegant kilogram-scale synthesis of D-malate has been developed using a maleate hydratase preparation from Pseudomonas pseudoalcaligenes. Finally, procedures are described for the synthesis of enantiomerically pure solketal and glycidol using, respectively, whole cell preparations of Comamonas testosteroni and Bacillus pasteurinanus containing the PQQ-dependent quinohaemoprotein ethanol dehydrogenase (QH-EDH).