Highly Selective Dimerization of Styrenes and Linear Co-dimerization of Styrenes with Ethylene Catalyzed by a Ruthenium Complex

Heads you win: An unusual head‐to‐head dimerization of styrenes has been developed using the zero‐valent ruthenium catalyst [Ru(η6‐cot)(η2‐dmfm)2] (cot=1,3,5‐cyclooctatriene, dmfm=dimethyl fumarate) in the presence of primary alcohols to give the homo‐dimer in high regio‐ and stereoselectivity. The catalyst system is also effective for the selective co‐dimerization of styrenes with ethylene to give the co‐dimer in high yield.