Copper (I)-N, N-Dimethyldipropylenetriamine Catalyzed Robust Homocoupling of Terminal Alkynes

A robust catalytic system consisting of Cu (I) -salt and dimethyldipropylenetriamine for the synthesis of 1-4-disubstituted 1, 3-diynes have been developed. The new protocol involves homocoupling of terminal alkynes in the presence of CuI or CuCl and DMAPAPA as ligand in acetonitrile. A seires of terminal alkynes having diverse functional groups are converted to corresponding 1, 3-diynes via homocoupling under ambient conditions within an hour in excellent yields upto 98 %. The current protocol avoids stoichiometric amount of copper salt and high cost palladium salt, and harsher condition.