General Access to N−CF3 Secondary Amines and Their Transformation to N−CF3 Sulfonamides

The synthesis of N-CF₃ compounds through fluorination or trifluoromethylation of N-containing compounds has been extensively investigated. However, general access to N-CF₃ compounds simply from N-CF₃ secondary amines is hampered by the challenging preparation and instability of these amines, as well as a much lower reactivity due to the strong electron-withdrawing nature and steric bulk of the trifluoromethyl moiety. Herein, we report a general and highly efficient synthesis of N-CF₃ secondary amines with excellent isolated yields via the addition of the in situ generated difluoromethyl imine (R-N=CF₂ ) intermediates with hydrogen fluoride, which is mildly produced by triethylsilane and silver fluoride. N-CF₃ sulfonamides, highly desirable but scarce at present, are easily accessible from these valuable building blocks through an unprecedented route. This study will bring new vitality to the synthesis of N-CF₃ compounds.