title: Influence of bases and ligands on the outcome of the Cu(I)-catalyzed oxidative homocoupling of terminal alkynes to 1,4-disubstituted 1,3-diynes using oxygen as an oxidant.
abstract: The efficient Cu(I)-catalyzed oxidative homocoupling of terminal alkynes in the presence of a base using an amine as a ligand and oxygen as an oxidant yields the symmetrical 1,3-diynes with yields of up to 99%. The outcome of the couplings critically depends on the proper choice of base and ligand as well as reaction conditions. Best results were observed with 2.0 mol % CuCl, 1.5 mol % TMEDA or DBEDA, and DBU or DABCO in acetonitrile.
authors.affiliation: Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364 002, Gujrat, India.
authors.forename: Subbarayappa
authors.initials: S
authors.lastname: Adimurthy
authors.forename: Chandi C
authors.initials: CC
authors.lastname: Malakar
authors.forename: Uwe
authors.initials: U
authors.lastname: Beifuss