Deracemization of Racemic Amine Using ω-Transaminase and a Nickel-Based Nanocatalyst

Chiral amines are key building blocks for the development of numerous bioactive compounds. In this study, we developed a concurrent chemoenzymatic cascade approach using ω-transaminase for the isomeric configuration inversion of a racemic amine mixture. One isomer was transaminated using ω-transaminase, generating coproduct ketones and an additional chiral substance. Then, the mixture underwent selective reductive amination of a ketone using a specially designed compatible nickel-based nanocatalyst, which transformed coproduct ketone to racemic amines while leaving the opposite enantiomer unchanged. The combination of the two steps in one reaction system functions as an overall isomeric configuration inversion system. Moreover, the desired chiral amines with an additional chiral substance were formed. The procedure consumed NH3 and generated H2O as the sole byproduct.