N-Heterocyclic Carbene (NHC) Organocatalytic One-Pot Reaction for the Enantioselective Synthesis of Fluoromethylated Chromenones.

An efficient carbene organocatalyzed route to enantioenriched chromenones, bearing one tri- or difluoromethylated stereogenic center in the β position of the carbonyl group, from o-allyloxybenzaldehydes is described. The one-pot transition-metal-free transformation exhibits a broad substrate scope and excellent enantioselectivity.