Homolytic displacement at saturated carbon in organocobaloximes. Part 4

Abstract

Benzyl and para-substituted benzylcobaloximes react with substituted arenesulphonyl chlorides under photochemical and anaerobic conditions at 0 °C to give a variety of products including the sulphones, bibenzyls, and benzyl ethers of dimethylglyoxime in variable yields. However, when the reactions are carried out in the presence of a 1 mol excess of pyridine, the yield of sulphones is increased by at least 20% in each case. The corresponding yield of bibenzyls is decreased and no trace of the benzyl ether of dimethylglyoxime is formed. On the other hand, the reaction of heteroaromatic methyl cobaloximes with arenesulphonyl chlorides form the corresponding sulphones as the exclusive organic product in good yield and with no side products. The reactions are interpreted in terms of a direct attack of the arenesulphonyl radical on the α carbon of the benzyl and heteroaromatic methyl ligand.