Highly Acyclic Selective Cobalt Catalysts for Butadiene Dimerization

Abstract

Butadiene is a simple unsubstituted diene predominantly used in polymerisation reactions and so far dimerisation reactions have focused on cyclic, Diels-Alder-type, products. We report unprecedented selectivity for the acyclic dimerisation of butadiene to produce 5-methyl-1,3,6-heptatriene and 1,3,6-octatriene using a bench stable cobalt catalyst. A series of 11 cobalt(II) complexes were prepared and optimised for acyclic selective dimerisation. The catalysts operated under mild reaction conditions and did not require the use of organometallic activators.