Steric and electrostatic effects in the addition of thiols to substituted norbornenes

Abstract

Free radical addition of alkanethiols to 7,7-dimethylnorbornene, bornene, and 1,4,7,7-tetramethylnorbornene and of arenethiols to 1,4,7,7-tetramethylnorbornene to give sulphides is described. The proportions of the products are interpreted in terms of the relative steric and electrostatic interactions between a bridged polycyclic olefin and a thiyl radical approaching from the exo- and endo-directions respectively. The product sulphides have been oxidised to sulphones; the exo-sulphones may be epimerised to give endo-sulphones.