Highly chemo- and regio-selective [2+2+2] cycloaddition of unsymmetrical 1,6-diynes with terminal alkynes catalyzed by Cp*Ru(cod)Cl under mild conditions

Ru(II)-catalyzed cycloaddition of unsymmetrical 1,6-diynes gives the desired cycloadducts in high yields with a regioselectivity meta : ortho = 88 : 12-98 : 2.