Titanocene-Catalyzed Reductive Domino Epoxide Ring Opening/Defluorinative Cross-Coupling Reaction.

Herein, we report a method for efficient synthesis of gem-difluorobishomoallylic alcohols starting from trifluoromethyl-substituted alkenes and epoxides via a titanocene-catalyzed reductive domino reaction, which consists of a Ti(III)-mediated radical-type ring opening and the following allylic defluorinative cross-coupling reaction via sequential radical addition and β-F elimination. Notably, complete regioselectivity and high tolerance of functionalities can be achieved in this reaction. Furthermore, diverse 6-fluoro-3,4-dihydro-2H-pyrans have been prepared through derivatization of the cross-coupling products in one single step.