Stable gem-trifluoromethyl anionic σ-complexes based on 1,3,5-tris(sulfonyl)benzene derivatives and their transformations

A convenient synthetic procedures is described to obtain gem-trifluoromethyl anionic σ-complexes of 1,3,5-tris(fluorosulfonyl)benzene, 1,3,5-tris(β,β,β-trifluoroethoxysulfonyl)benzene, 1,3,5-tris(trifluoromethylsulfonyl)benzene as well as of 1,3,5-trinotrobenzene. Conditions for easy oxidation of these adducts into corresponding 2,4,6-tris(substituted)benzotrifluorides have been found. It is shown that the latter add trifluoromethyl anion to the 1 and 3 positions of the aromatic ring forming new anionic σ-complexes in different ratio. Structures and relative stabilities of the anionic adducts are discussed based on RI-MP2 quantum chemical calculations.