Photoinduced Synthesis of α-Amino Ketones from Nitroarenes and α-Hydroxy Ketones

Abstract

α-Amino ketones are valuable synthons and are present in many pharmacologically active molecules, but their synthesis is challenging. Herein, we disclose a photoinduced, operationally simple method for the synthesis of α-amino ketones, which is particularly useful for ketone retention cases. Coupling between a wide range of nitroarenes, a class of feedstock chemicals, and readily available α-hydroxy ketones, catalyzed by an in situ-formed electron-donor–acceptor (EDA) complex, provides facile access to structurally diverse α-amino ketones. The reaction is confirmed as a stepwise process: (1) photoinduced transformation of nitroarenes into PhN(OBpin)₂ and azobenzene; (2) radical-mediated coupling of azobenzene and α-hydroxy ketones. Gram-scale preparation of α-amino ketones and Cu(OAc)₂/CPA-promoted kinetic resolution of racemic α-amino ketones demonstrate the synthetic utility of this method.