Structural Characterization of Bismuth( III ) and Antimony( III ) Chlorotriflates: Key Intermediates in Catalytic Friedel−Crafts Transformations

Chlorotriflates of antimony and bismuth Cl n M(OSO 2 CF 3 ) 3− n ( n = 1 or 2) are believed to be metallic intermediates of major importance in Friedel−Crafts reactions that use Bi(OSO 2 CF 3 ) 3 , Sb(OSO 2 CF 3 ) 3 , the systems BiCl 3 /CF 3 SO 2 OH or SbCl 3 /CF 3 SO 2 OH as catalysts. Unknown until now, the compounds ClBi(OSO 2 CF 3 ) 2 ( 1 ) and Cl 2 Sb(OSO 2 CF 3 ) ( 2 ) have been synthesized by reaction of MCl 3 (M = Bi, Sb) with triflic acid. After crystallization from THF, 1 and 2 were investigated in the solid state by X‐ray crystallography. Their use as catalysts in benzoylation of toluene, acylation of m ‐xylene, and sulfonylation of toluene led to conclusive results, thus giving weight to their key role as intermediates in Friedel−Crafts reactions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)