Asymmetric Fluorocyclization of Difluoroalkenes with Concomitant Formation of a Trifluoromethyl Group.

Asymmetric electrophilic fluorination of difluoroalkenes remains undeveloped because of the poor reactivity of difluoroalkenes with electrophiles. However, such reactions, if feasible, are expected to be useful for the synthesis of chiral heterocyclic compounds with a trifluoromethyl group at the stereogenic center. In this Letter, we disclose the first example of asymmetric fluoroamide cyclization of difluoroalkenes using our dianionic phase-transfer catalyst. This reaction provides unique chiral trifluoromethylated oxazoline derivatives at a synthetically useful level.