Copper-Catalyzed Trifluoromethylthiolaton and Radical Cyclization of N-Phenylpent-4-Enamides to Construct SCF3-Substituted γ-Lactams

An efficient method involving copper-catalyzed trifluoromethylthiolation and radical cyclization of N-phenylpent-4-enamides using readily available and stable AgSCF3 as the trifluoromethylthiolating reagent is described. The method enables the synthesis of a series of potential medicinally valuable trifluoromethylthio-substituted γ-lactams and relative 2-oxazolidinone derivatives with broad functional group compatibility. Mechanistic investigations indicated that this reaction involved amidyl radical-initiated cascade 5-exo-trig cyclization followed by trifluoromethylthiolation, resulting in the formation of new C-N and C-S bonds.