Recent studies on organic synthesis mediated by radical species of peroxysulfur compounds

Reaction of superoxide ion (O2(-.)) with o-nitrobenzenesulfonyl chloride yi elds a material with strong oxidizing ability, capable of oxidizing benzyli c methylenes to the aryl ketones, benzylic ethers to benzoic esters, hydraz ones to ketones, and electron deficient alkenes regioselectively to epoxide s. The oxidizing species is tentatively assigned the o-nitrobenzenesulfonyl peroxy radical structure 1. Tetrabutylammonium hydrogen sulfate, on treatm ent with potassium persulfate under phase transfer conditions, gives tetrab utyl ammonium peroxydisulfate 2, a new oxidizing agent capable of oxidizing primary and secondary alcohols to the corresponding aldehydes and ketones in almost quantitative yields in aprotic solvents under anhydrous condition s; 2 is evidently a source of tetrabutylammonium sulfate radical 3. Further reactions include formation of the tetrahydropyranyl or tetrahydrofuranyl ether derivatives on reaction with alcohols, regioselective iodinations of anisyl derivatives, and alpha,beta-unsaturated ketones or esters, nucleophi lic epoxidations of alpha,beta-unsaturated ketones, and an interesting addi tion of the 1,3-dioxolanyl group to electron deficient alkenes, including a conversion of 1-nitrocyclohexene into a masked alpha-formylcyclohexanone.