Iridium-catalyzed dimerization of terminal alkynes to (E)-enynes, (Z)-enynes, or 1,2,3-butatrienes

The iridium complex generated in situ from [Ir(cod)Cl](2) and a phosphine ligand catalyzed the dimerization of terminal alkynes to give (E)-enyne, (Z)-enyne, or 1,2,3-butatriene derivatives in the presence of triethylamine. The triarylphosphine complex selectively yielded linear (E)-enynes for silylethynes, while the tripropylphosphine complex provided linear (Z)-enynes for silylalkynes or 1,2,3-butatrienes for tert-alkylethynes.