Silver‐Catalyzed Isocyanide–Isocyanide [3+2] Cross‐Cycloaddition Involving 1,2‐Group Migration: Efficient Synthesis of Trisubstituted lmidazoles

Abstract Imidazole ring is an important five‐membered aromatic heterocycle that is widely present in natural products and synthetic molecules. The isocyanide–isocyanide [3+2] cross‐cycloaddition reaction constitutes a straightforward method to access imidazoles starting from the easily available chemicals. So far, only three successive reports are known and all lead to the formation of 1,4‐disubstituted imidazoles. Here, we report the first isocyanide–isocyanide [3+2] cross‐cycloaddition reaction allowing for the formation of 1,4,5‐trisubstituted imidazoles under silver catalysis. An unexpected 1,2‐migration of sulfonyl, alkoxycaybonyl, and carbamoyl groups took place during the cyclization process that is responsible for the formation of trisubstituted imidazoles. This report displayed a mechanistically novel synthetic method toward a variety of imidazole derivatives, which are otherwise difficult to access by conventional methods.