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 ofN-phenylpent-4-enamides using readily available and stable AgSCF3as the trifluoromethylthiolating reagent is described. The method enables the synthesis of a series of potential medicinally valuable trifluoromethylthio-substitutedγ-lactams and relative 2-oxazolidinone derivatives with broad functional group compatibility. Mechanistic investigations indicated that this reaction involved amidyl radical-initiated cascade5-exo-trigcyclization followed by trifluoromethylthiolation, resulting in the formation of new C-N and C-S bonds.