Copper(I)-Catalyzed Regioselective Ullmann-Type Coupling of Primary Carbamates and 5-Substituted-1,2,3-Triiodobenzenes: Facile Synthesis of 2,3-Diiodinated N-Arylcarbamates

An efficient and unprecedented synthesis of 2,3-diiodinated N-aryl carbamate derivatives through highly regioselective Ullmann-type C–N arylation reactions of 5-substituted-1,2,3-triiodobenzenes and primary carbamates is described. Remarkably, the amination reactions proceeded exclusively at the terminal positions, the less sterically hindered, and the most regioactive positions. The highest yields were isolated from a combination between electron poor 1,2,3-triiodoarenes and ethyl carbamates. The optimized conditions were found to be suitable for many functional groups. This report discloses the first and unprecedented method to make 2,3-diiodinated N-aryl carbamates that is efficient, general in scope, highly regioselective and gives truly remarkable precursors for other transformations.