Study On The Synthesis Of Thioethers Using Sulfonyl Chlorides As The Sulfur Sources

Thioethers are of great significance in the fields of material,medicine and pesticide.Therefore,the synthetic method of thioethers has drawn much attentions of chemists.In1978,Migita et al.reported the first example of palladium-catalyzed reactions of aryl halides with thiophenols(alcohols)for the synthesis of aryl sulfides.The synthetic method of thioethers has gradually become one of the research hotspots.In the past decades,various sulfur sources,such as thiophenols(alcohols),disulfides,thioureas,potassium xanthates,thiocyanates,sodium sulfites,sulfonyl hydrazines,carbon disulfides and sulfonyl chlorides have been used for the synthesis of thioethers.However,compared to thiophenols(alcohols)and disulfides,less reports have been published by using other sulfur sources.As the vigorous development of thioethers synthesis,the use of sulfonyl chlorides as the sulfur sources has attracted more and more attentions.In this paper,the synthesis of thioethers with sulfonyl chlorides as the sulfur sources were developed,the main contents are shown as follow:The synthesis of aryl methyl sulfides from aryl sulfonyl chlorides with dimethyl carbonate has been developed.By using dimethyl carbonate as a green solvent,as well as the C1 source assist by sodium iodide,with aryl sulfonyl chlorides as cheap and easily available sulfur sources,various aryl methyl sulfides were obtained with moderate to excellent yield via a reductive coupling process in the presence of tin powder and triphenylphosphine.In addition,alkyl sulfonyl chlorides and dibenzyl carbonate could also be used as suitable substrates in this strategy.Nickel-catalyzed desulfonative cross-coupling of benzyl sulfonyl chlorides with aryl sulfonyl chlorides for the synthesis of asymmetric thioethers has been developed.By using benzyl sulfonyl chlorides as electrophiles,aryl sulfonyl chlorides as the sulfur sources,manganese powder as reducing agent under bis(tricyclohexylphosphine)nickel dichloride/4,4-di-tert-butylbipyridine catalyzed conditions via a desulfonylation process,a variety of asymmetric thioethers were successfully synthesized in moderate to excellent yields with good functional group tolerance.It is the first example of nickelcatalyzed synthesis of asymmetric thioethers by applying two different types of sulfonyl chlorides.