3-ELECTRON S(N)2 REACTIONS OF ARYLCYCLOPROPANE CATION RADICALS .2. STERIC AND ELECTRONIC EFFECTS OF SUBSTITUTION

The nucleophilic substitution reactions on substituted arylcyclopropan e cation radicals were studied by a combination of methods including p roduct studies, time-resolved laser flash photolysis, kinetic isotope effects, and quantum chemical calculations. The reactions were found t o proceed stereospecifically with inversion of configuration, with hig h regioselectivity for nucleophilic attack at the more substituted car bon atom, and with very small steric effects. Electronic effects on th e nucleophilic substitution regiochemistry and the rate constants were found to be substantial for substituents on the cyclopropane moiety a nd on the aryl ring.