Highly enantioselective synthesis of α-trichloromethyldihydropyrans catalyzed by bifunctional organocatalysts

The enantioselective Michael addition of α-cyanoketones to α,β-unsaturated trichloromethyl ketones was firstly reported. With a phenylalanine-derived bifunctional piperazine/thiourea catalyst, a series of α-trichloromethyldihydropyrans were obtained with up to 95% ee and 99% yield.