Selective Dehydrogenative Coupling of Ethylene to Butadiene via an Iridacyclopentane Complex.

An iridium complex is found to catalyze the selective dehydrogenative coupling of ethylene to 1,3-butadiene. The key intermediate, and a major resting state, is an iridacyclopentane that undergoes a surprisingly facile β-H elimination, enabled by a partial dechelation (κ3-κ2) of the supporting 3,5-dimethylphenyl-2,6-bis(oxazolinyl) ligand.