Copper-catalyzed cross-coupling reactions of bromoalkynols with terminal alkynes in supercritical carbon dioxide

Copper-catalyzed cross-coupling reactions of bromoalkynols and terminal alkynes were carried out in supercritical carbon dioxide (SCCO2) to afford the corresponding unsymmetrical diynes with good yields. The reaction is sensitive to temperature and the pressure of CO,. Methanol, as a cosolvent of scCO(2), could promote dissolution of the inorganic salt and thus facilitated the reaction. This new heterocoupling reaction system is more environmentally friendly than more traditional methods, since it uses scCO(2) as solvent and sodium acetate as base instead of amines.