Highly enantio- and diastereoselective synthesis of alpha-trifluoromethyldihydropyrans using a novel bifunctional piperazine-thiourea catalyst

The first enantioselective Michael addition of alpha-cyanoketones to alpha,beta-unsaturated trifluoromethyl ketones using a novel piperazine-thiourea catalyst was described. The resulting alpha-trifluoromethyldihydropyrans were obtained in high yields and with up to 95% ee within a short reaction time. A useful transformation of the chiral adduct was also illustrated.