K-10 montmorillonite-catalyzed solid phase diazotizations: environmentally benign coupling of diazonium salts with aromatic hydrocarbons to biaryls
A new heterogeneous catalytic diazotization and subsequent coupling of diazonium salts with aromatics for the synthesis of biaryls is described. The method involves the solid phase diazotization of anilines and the successive C–C bond formation of the diazonium salt with alkylbenzenes. Excellent yields were obtained for a broad range of anilines and aromatic nucleophiles. The reaction was carried out using K-10 montmorillonite as an acid catalyst and medium as well. The high selectivity, metal-free, recyclable catalyst, easy work up, and absence of harmful waste make the process a sustainable alternative to available methods.