The persistent radical effect: a prototype example of extreme, 105 to 1, product selectivity in a free-radical reaction involving persistent .cntdot.CoII[macrocycle] and alkyl free radicals

Abstract

Thermolysis of the coenzyme B 12 model complex, 1, leads to an equilibrium between 1 and the benzyl migration product 2, but for to even a few percent of the usual radical-recombination product bibenzyl, eq 1. Further investigation of this intermolecular reaction between freely diffusing radicals has revealed a selectivity of ca. 10 5 to 1 (i.e., 99.999%) for 1 and 2 in comparison to bibenzyl (0.001%)