Mechanism and Origins of Regio- and Stereoselectivities in Iridium-Catalyzed Isomerization of 1‑Alkenes to <i>trans</i>-2-Alkenes

Density functional theory calculations were performed to investigate the iridium-catalyzed isomerization of 1-alkenes to trans-2-alkenes. The computations show that the originally proposed π-allyl mechanism is kinetically unfeasible. A metal–ligand cooperative mechanism was suggested to account for the experimental results. The reaction was found to begin with the C­(sp2)–H oxidative addition of the pyridine ligand to give the Ir­(III) hydride intermediate, from which the isomerization further takes place via the insertion/elimination pathway