<i>N</i>,<i>N′</i>-Dioxide/Gadolinium(III)-Catalyzed Asymmetric Conjugate Addition of Nitroalkanes to α,β-Unsaturated Pyrazolamides

Abstract

A highly efficient N,N'-dioxide/Gd(III) complex has been developed for the enantioselective conjugate addition of nitroalkanes to α,β-unsaturated pyrazolamides. Under mild reaction conditions, a series of γ-nitropyrazolamides were obtained in good to excellent yields (up to 99%) with excellent enantioselectivities (up to 99% ee). What's more, the optically active products could be easily transformed into γ-nitroesters which were key intermediates for the preparation of paroxetine, pregabalin and boclofen.