Sc(OTf)3-Catalyzed C–C Bond Cleavage of Unactivated Acylazaarenes with 1,2-Diamines to Afford Azaarenes and Imidazoles

We report a method for cleaving the C(O)-sp2C bonds of unactivated acylazaarenes via benzimidazoline intermediates using a mild redox neutral catalytic system involving scandium triflate. This method avoids the need for preactivation or transition metal catalysts, enabling efficient C-C bond cleavage in a broad range of substrates, including 2-acylimidazoles, 2-acylpyridines, 2-acylpyrole, and even nonchelating 3-acylindole, in which direct C-C bond cleavage has not been previously achieved.