Palladium-catalyzed defluorinative alkynylation of polyfluoroalkyl ketones with alkynes for the synthesis of fluorinated fused furans

A Pd-catalyzed C-F bond alkynylation of polyfluoroalkyl ketones with terminal alkynes has been developed. The method gives access to a range of modular perfluoroalkyl- and alkynyl-substituted furan derivatives in moderate yields with high chemoselectivity and regioselectivity. The key to the success of the present cascade reaction mainly relies on the well-controlled sequence of functionalization and alkynylation of multiple C(sp(3))-F bonds. Mechanistic studies showed that the reaction presumably proceeded through a chelation-assisted oxidative addition of Pd to the C-F bond.