An Alternative Mechanism for the Cobalt-Catalyzed Isomerization of Terminal Alkenes to (Z)-2-Alkenes

The cobalt-catalyzed selective isomerization of terminal alkenes to the thermodynamically less-stable (Z)-2-alkenes at ambient temperatures takes place by a new mechanism involving the transfer of a hydrogen atom from a Ph2PH ligand to the starting material and the formation of a phosphenium complex, which recycles the Ph2PH complex through a 1,2-H shift.