Theoretical analysis of the reaction pathway and the effect of the axial ligand for 3-oxobutylideneaminatocobalt(II)-catalyzed cyclopropanation

structure: see text] The reaction pathway of the cyclopropanation catalyzed by the 3-oxobutylideneaminatocobalt(II) complex was analyzed by the density functional method to reveal that the axial donor ligand produced two prominent effects. One is that the activation energy for the formation of the cobalt carbene complex was reduced and that the activation energy for the cyclopropanation step was increased. The other is that the distance of the carbene carbon above the ligand plane was shortened during the cyclopropanation step.