DFT study of the asymmetric nitroaldol (Henry) reaction catalyzed by a dinuclear Zn complex

We report the mechanism of asymmetric nitroaldol (Henry) reaction catalyzed by a dinuclear Zn complex using density functional theory. The experimentally proposed catalytic cycle is validated, in which the first step is the deprotonation of nitromethane by the ethyl anion of the catalyst, subsequently a C-C bond formation step, and then the protonation of the resulting alkoxide. Three mechanistic scenarios (differing in binding modes) have been considered for the C-C bond formation step. The origin of the enantioselectivity is discussed. Our calculations supported that the S configurations are the major products, which is in agreement with the experimental observations.