Enantioselective synthesis of 4-(dimethylamino)pyridines through a chemical oxidation-enzymatic reduction sequence.: Application in asymmetric catalysis

Enantiomerically pure 4-(dimethylamino)3-(1-hydroxyalkyl)-pyridines and 4-(dimethylamino)3-[hydroxy(phenyl)methyl]pyridine have been prepared through efficient chemoenzymatic routes. For this purpose different lipases and oxidoreductases have been tested in the preparation of optically active 4-chloro derivatives and baker's yeast was found to be an excellent catalyst for the bioreductions of the corresponding ketones. Their applications as enantioselective nucleophilic catalysts have been studied, important catalytic properties were observed in the stereoselective construction of quaternary centers.