Kinetics, products, and mechanism of the reaction of diphenylcarbonyl oxide with sulfoxides

The kinetics of the reactions of diphenylcarbonyl oxide with dimethyl, di-n -hexyl, diphenyl, dibenzyl, and n-hexylbenzyl sulfoxides in acetonitrile wa s studied by flash photolysis at 295 K. The oxidation of sulfoxide affords the corresponding sulfone as the main reaction product, and diphenyl sulfid e also forms in the case of Ph2SO, Solvent effect on the reaction kinetics and the composition of the reaction products was studied. The reaction mech anism is discussed, which includes two parallel pathways: the nucleophilic attack of carbonyl oxide at the sulfur atom of sulfoxide and the formation of the cyclic sulfurane intermediate via the electrophilic 1,3-cycloadditio n of Ph2COO at the S=O bond. The sulfurane undergoes fragmentation via para llel channels to form sulfone or sulfide.