A new class of urea-substituted cinchona alkaloids promote highly enantioselective nitroaldol reactions of trifluoromethylketones

The first class of bifunctional cinchona-alkaloid catalysts incorporating a urea moiety at C-5' has been developed. These materials catalyze the efficient and highly enantioselective 1,2-addition of nitromethane to trifluoromethylketones to form synthetically pliable products incorporating a quaternary stereocenter. Excellent product yields and levels of enantiomeric excess are possible, and the optimum catalyst structure is capable of promoting the Henry reaction involving alkyl trifluoromethylketones with unprecedented enantioselectivity.