Water-Driven Isomerization Control: Dinuclear Cobalt-Catalyzed Monoisomerization of Linear Terminal Alkenes

The development of binuclear earth-abundant metal catalytic
systems,
drawing inspiration from metalloenzymes, has attracted considerable
research interest in homogeneous catalysis. While current catalytic
systems for alkene isomerization are mainly limited to monometallic
catalysis, emerging opportunities in dinuclear catalysis present transformative
potential, although their working mechanisms are still elusive. Herein,
a dinuclear cobalt complex-catalyzed monoisomerization of linear alkyl
α-olefins to 2-alkenes is disclosed, which is unusual because
H2O is found to play a significant role in the control
of regioselectivity, turning a mixture of multiisomers into 2-alkenes
in high yields with excellent regioselectivity. DFT calculations indicated
that the hydroxyl exchange step between H2O and the Co–H
active intermediate acts as a functional hindrance to control the
site selectivity for the selective monoisomerization.