CCl4-TMEDA-CuCl-A Novel Convenient Catalytic System for Dimerization of Terminal Acetylenes in Mild Conditions

A novel catalytic system for homocoupling terminal acetylenes was elaborated based on CuCl as a catalyst (10 mol%), TMEDA as a base and CCl4 as an oxidant. The influence of the solvent, base, amount of catalyst and CCl4 on the reaction was investigated. Methanol was found to be the solvent of choice. The broad synthetic scope of the reaction was demonstrated. Diynes with various substituents were prepared in up to 92% yields. The possible reaction mechanism is discussed.

Automated summary

A novel catalytic system for homocoupling terminal acetylenes was developed based on CuCl as a catalyst, TMEDA as a base, and CCl4 as an oxidant. The reaction was studied in terms of solvent, base, amount of catalyst, and CCl4. Methanol was found to be the preferred solvent, and the reaction showed a wide synthetic scope with yields up to 92% for diynes with various substituents. The possible reaction mechanism was discussed.