A new chiral
N,
N'-dioxide-Cu
I catalyst has been developed for the asymmetric Henry (nitroaldol) reaction.The approach benefited from the easy modification of the chiral space. As the highly effective
N-oxideligand,
1d has been adopted for the Henry reaction with both aromatic and heteroaromatic aldehydes.The corresponding nitro-alcohol products were obtained in good yields with high enantiomeric excessesup to 98%. Moreover, -ketoesters were also catalyzed by this catalyst to give attractive optically active-hydroxy -nitro esters containing chiral quaternary carbon centers (up to 99% ee). On the basis of acombination of several techniques including the
1H NMR, ESI-HRMS, and MM2 calculations, the proposedmechanism was presented to explain the origin of reactivity and asymmetric inductivity.
