Ketyl Radicals Formed in Grignard Reaction. III. Steric Effects on the Formation of Radicals

Abstract

Abstract In the reaction of benzophenone with phenylmagnesium bromide, the concentration and life-time of the ketyl radical were influenced greatly by the substitution of ortho-hydrogen atoms of both the two reactants by methyl group. From the results of visible absorption and ESR measurements and also of product-analysis, the ketyl radical was considered to be a common intermediate towards normal and abnormal reaction products. The existence of an equilibrium between monomeric and dimeric states of the ketyl radical was also proposed.