Catalytic asymmetric nitroaldol reaction of α,α-difluoro aldehydes mediated by rare earth-lithium-BINOL complexes

Abstract

Rare earth-Li-BINOL complexes were used to catalyze nitroaldol reactions of α,α-difluoro adehydes with nitromethane in a good enantioselective manner. The optical yields of nitroaldol 2a depend on the size of rare earth metals, and an Sm-Li-BINOL complex gave the highest enantioselectivity. The enantiotopic face selection of α,α-difluoro aldehyde 1a was found to be different from that of nonfluorinated aldehydes employed in the usual catalytic asymmetric nitroaldol reactions.