A molecular modeling study of the changes of some steric properties of the precatalysts during the olefin metathesis reaction.

The productive self-metathesis of 1-octene with a series of new phosphine ligated Grubbs-type precatalysts was studied. The resulting structures were used to compare some steric properties of the new precatalysts with those of well-known precatalysts. The possibility of α-CC agnostic stabilization as well as the ability of the ligands to shield the metal was studied. A comparison of the obtained data, pointed to the unlikelihood that α-CC agostic stabilization is a major contribution to the stabilization of the various metallacyclobutane rings. The similarity in the ability of the ligands to shield the metal also raised questions about the comparison of experimentally observed trends with those obtained theoretically.