Chiral Pyridoxal-Catalyzed Asymmetric Biomimetic Transamination of α-Keto Acids
摘要:
A series of chiral pyridoxals 8 and 9 have been developed from commercially available pyridoxine and (S)-alpha,alpha-diarylprolinols. The pyridoxals exhibited good catalytic activity in an asymmetric transamination of alpha-keto acids with 2,2-diphenylglycine (7f) as the amine source to give various alpha-amino acids in 29-85% yields with 53-80% ee's. The current asymmetric transamination has successfully mimicked a complete biological transamination process characterized by two half-transaminations, a small chiral pyridoxal molecule acting as the catalyst, and enantioselective control.