Synthesis of 2,2,2-Trifluoroethyl Oxazoles, Oxazolines and Furans via Alkyne Oxytrifluoromethylation

This study reports an oxytrifluoromethylation method for construction of oxazoles and furans motif and the concurrent incorporation of a 2,2,2-trifluoroethyl group at the aromatic C5-position. High-valent copper(III) trifluoromethyl compounds are crucial to this reaction that induces oxy-trifluoromethylation of alkynes with a pendant amide/enol group functioning as the oxygen-nucleophile. A wide substrate scope is demonstrated with high efficiency and with broad functional group tolerance. Late-stage functionalization of dehydrocholic acid, a complex drug compound, is accomplished to show the potential of this method for practical drug design.