Transition Metal Catalysis And Non-metal-promoted CS Bond Synthesis New Methods

Because of the compounds which contain sulfur play an important role in agricultural?new pharmaceutical and chemical agents,there is a profound significance in synthesis of sulfur-containing compounds.In recent years,transition metal catalyzed and non-metallic promoted the formation of C-S bond got certain development.We also did some research to construct C-S bond which include two parts:the synthesis of aryl sulfone compounds by metal catalyst and the synthesis of aryl methyl ethers by non-metal promotion,which include:1.The direct sulfonylation of 2-aryloxypyridines on the ortho-position of benzene ring was developed using Pd(OAc)2 as catalyst?K2CO3 as base?sulfonyl chlorides as sulfonylation reagents and 2-pyridyloxyl as the directing group.The reaction exhibits a good tolerance for a broad range of general functional groups.No matter electron-rich substrates or electron-deficient substrates can react under the optimal condition.Most of the substrates got moderate yields,and pyridine is a removable directing group.The ortho-sulfonylated phenol was synthesized expediently from the sulfonylation product by the removal of pyridyl group.The six-membered metallacycles were believed to be generated as the intermediates according to the related literature and our research on the mechanism of the reaction.2.Aryl methyl thioethers and methylene-bridged arylamines were synthesized via highly regioselective para-methylthiolation/bridging methylenation of arylamines using DMSO as the methylthio or methylene source in the presence of NH4I under metal-free conditions.For the substrates with both electron-donating and electron-withdrawing substituents,the reaction proceeded smoothly and gave moderate to good yields.In most cases,the reactions of anilines with electron-donating group on the benzene ring mainly gave methylthiolation products,and the reactions of anilines with some electron-withdrawing group on the benzene ring gave methylene-bridged products,while disubstituted or phenyl substituted anilines gave both methylthiolation and bridging methylenation products.The research of this mechanism shows that the methylthiolation of arylamines undergone methylthio radical intermediates,and the mechanism of bridging methylenation is that DMSO release formaldehyde firstly,then formaldehyde reacts with anilines.