cobalt(II) chloride in acetone T=80°C; 1.5 h;

in dichloromethane T=70°C; 36 h;

1: With hex-3-yne in benzene T=40°C; 22 h; Inert atmosphere; 2: With ammonium cerium (IV) nitrate in diethyl ether; benzene T=20°C; 3 h; Inert atmosphere; chemoselective reaction;