An ab initio study of 1,5-suprafacial shifts in 5-substituted 1,3-cyclopentadienes

Abstract

A computational study of the degenerate 1,5-suprafacial migration of the 5-substituted cyclopentadienes is presented. The substituents considered are the Group 14–17 elements of the second through fifth periods, saturated by hydrogens as needed to fulfill normal valence requirements. The geometry of most transition states are remarkably similar in the carbon framework. The activation barrier to migration was shown to correlate well with a dimensionless "stretching" parameter, especially at the MP2 level.Key words: 5-substituted 1,3-cyclopentadiene, 1,2-haptotropic shift, 1,5-suprafacial shift, ab initio, transition states.