On-Surface Intramolecular Dehalogenation of Vicinal Dibromides for the Direct Formation of C–C Double Bonds

Abstract

The intramolecular dehalogenation reaction as an essential step is generally involved in the deprotection of carbon–carbon double bonds in solution chemistry. However, harsh reaction conditions often limit the functional group compatibility and cause the selectivity problems. In comparison with traditional solution reactions, on-surface chemical reactions always occur on metal substrates, which could serve as catalysts to effectively reduce the reaction barriers in many cases. On the other hand, on-surface intermolecular dehalogenative homocoupling reactions have been extensively demonstrated, while, to our knowledge, intramolecular dehalogenation reactions are less discussed on surfaces. Herein, by the combination of high-resolution scanning tunneling microscopy imaging and density functional theory calculations, we introduce the vicinal dibromo group on chemically different surfaces, such as Cu(110), Ag(110), and Au(111), respectively, to investigate the generality of intramolecular dehalogenation reactions. As a result, we successfully achieved the direct formation of C–C double-bonded products in a facile manner on all three surfaces.