Influence of Bases and Ligands on the Outcome of theCu(I)-Catalyzed Oxidative Homocoupling ofTerminal Alkynes to 1,4-Disubstituted 1,3-DiynesUsing Oxygen as an Oxidant

摘要

The efficient Cu(I)-catalyzed oxidative homocoupling ofterminal alkynes in the presence of a base using an amineas a ligand and oxygen as an oxidant yields the symme-trical 1,3-diynes with yields of up to 99%. The outcome ofthe couplings critically depends on the proper choice ofbase and ligand as well as reaction conditions. Best resultswere observed with 2.0 mol % CuCl, 1.5 mol % TMEDAor DBEDA, and DBU or DABCO in acetonitrile.