Co(OAc)2‑Catalyzed Trifluoromethylation and C(3)-Selective Arylation of 2‑(Propargylamino)pyridines via a 6-Endo-Dig Cyclization

A Co­(OAc)2-catalyzed trifluoromethylation and subsequent C(3)-selective arylation of 2-(propargylamino)­pyridines has been developed. A new 6-endo-dig cyclization involving an unprecedented C(3) selective arylation of the pyridines instead of a commonly observed 5-exo-dig cyclization with “N” is realized. Moreover, the study presents the first case of the installation of a trifluoromethyl group into electron-deficient azaarenes. The process delivers an efficient cascade approach to new trifluoromethylated 1,8-naphthyridine structures with a broad substrate scope.