Catalytic Asymmetric Reductive Amination of Aldehydes via Dynamic Kinetic Resolution

A novel organocatalytic asymmetric reductive amination of aldehydes has been developed. Treating racemic α-branched aldehydes with p-anisidine and a Hantzsch ester in the presence of our previously developed phosphoric acid catalyst, TRIP, gave β-branched secondary amines in excellent yields and enantioselectivities via an efficient dynamic kinetic resolution. The process is applicable to several different aromatic aldehydes and amines but gives slightly reduced enantiomeric ratios with aliphatic aldehydes