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 …

S Adimurthy, CC Malakar, U Beifuss

Index: Adimurthy, Subbarayappa; Malakar, Chandi C.; Beifuss, Uwe Journal of Organic Chemistry, 2009 , vol. 74, # 15 p. 5648 - 5651

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Citation Number: 113

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.