Studies on organophosphorus compounds XXIV. the formation of disulfides from sulfoxides

The reaction of DMSO with the dimer of p-methoxyphenylthionophosphine sulfide, 1, produces dimethyl disulfide and causes partly deoxygenation of DMSO to give dimethyl sulfide. P4S10 and DMSO give dimethyl disulfide in lower yield, a result not observed in recent reports. 5, 6 The cyclic sulfoxide, tetrahydrothiophene sulfoxide, 2, also reacted with 1 to give the cyclic disulfide, 1,2-dithiane, 3.