Friedel–Crafts Type Methylation with Dimethylhalonium Salts

Abstract

The dimethylchloronium salt [Me₂ Cl][Al(OTeF₅ )₄ ] is used to methylate electron-deficient aromatic systems in Friedel-Crafts type reactions as shown by the synthesis of N-methylated cations, such as [MeNC₅ F₅ ]⁺ , [MeNC₅ F₄ I]⁺ , and [MeN₃ C₃ F₃ ]⁺ . To gain a better understanding of such fundamental Friedel-Crafts reactions, the role of the dimethylchloronium cation has been evaluated by quantum-chemical calculations.