Amide Groups Switch Selectivity: C–H Trifluoromethylation of α,β-Unsaturated Amides and Subsequent Asymmetric Transformation

The first direct C–H β-trifluoromethylation of unsubstituted or α-alkyl-substituted α,β-unsaturated carbonyl compounds under metal-free conditions was realized with excellent regio- and stereoselectivity as well as a very broad substrate scope. Both olefinic and allylic trifluoromethylation products are accessible with high selectivities by altering the substrate substitutions. The resultant olefinic products, namely (E)-β-trifluoromethyl (CF₃) α,β-unsaturated hydroxamic acid derivatives, served as acceptors in organocatalytic asymmetric Michael addition reactions to give hydroxamic acid derivatives bearing a chiral CF₃-substituted stereocenter with high enantioselectivities.