Synthesis and Reactivity of N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide as a New Type of Trifluoromethylating Agent

N-Trifluoromethyl-N-nitrosotrifluoromethanesulfonamide (TNS-Tf) was synthesized in a 58% yield by the reaction of trifluoronitrosomethane with hydroxylamine followed by the treatment with trifluoromethanesulfonyl fluoride in the presence of a base. TNS-Tf was demonstrated to be an effective trifluoromethylating agent photochemically or thermally for aromatics, thiols, disulfides, and uridine derivatives. The insertion reaction by two trifluoromethyl groups of TNS-Tf to the sulfur-sulfur bonds was observed in the reaction with disulfides having electron-withdrawing groups, giving 2 mols of trifluoromethylthio compounds. Furthermore, TNS-Tf served as a good reagent for mild and convenient in situ generation of trifluoromethylcopper complex which converted iodoaromatics to trifluoromethyl-substituted aromatics in good yields. Similarly, N-trifluoromethyl-N-nitrosononafluoro-1-butanesulfonamide (TNS-Nf) was synthesized in a 36% yield. The examination of the reactivity indicated that this type of N-nitroso sulfonamides became to be sources of both perfluoroalkyl radicals contained.