N,N '-Dioxide/Gadolinium(III)-Catalyzed Asymmetric Conjugate Addition of Nitroalkanes to alpha,beta-Unsaturated Pyrazolamides

A highly efficient N,N'-diokide/Gd(III) complex has been developed for the enantioselective conjugate addition of nitroalkanes to alpha,beta-unsaturated pyrazolamides. Under mild reaction conditions, a series of gamma-nitropyrazolamidos 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 gamma-nitroesters which were key intermediates for the preparation of paroxetine, pregabalin and boclofen.