Phosphoric Acid Catalyzed Dynamic Kinetic Resolution of Azlactones

Significance

Lu and Birman report the dynamic kinetic resolution (DKR) of racemic azlactones via a chiral Brønsted acid promoted alcoholysis. After intensive optimization, the combination of azlactones 1 bearing a 3,5-dimethoxyphenyl group at the C2 position, 1-naphthylmethanol (2) as the nucleophile and chiral phosphoric acid 3 turned out to give good results in terms of yields and enantio­selectivities. While substrates with aromatic C4 substituents were resolved very efficiently, the ­results with aliphatic groups were inferior.