Direct use of CO2 for O-arylcarbamate synthesis via mild Cu(II)-catalyzed aerobic C-H functionalization in pincer-like macrocyclic systems

Cu(II)-catalyzed C-H functionalization for the synthesis of O-arylcarbamates in a model pincer-like arene substrate using CO2 gas as C1-synthon is shown to proceed via aryl-Cu(III) intermediate species at room temperature. Indeed, stoichiometric experiments have been performed starting from an isolated Cu(III) complex and carbamic ammonium salts. A catalytic version has been then developed using a model arene substrate and a Cu(II) salt through C-H activation. Finally, effective Cu(II)-catalyzed C-H functionalization was achieved by in situ generation of carbamates from amines and CO2 gas. (C) 2017 Elsevier B.V. All rights reserved.