The Application Of Sulfohydrazide In The Organic Synthesis In Water

"Green Chemistry" is closely related to the theme of sustainable development,and has become Environmentally Friendly Chemistry,Environmentally Benign Chemistry or Clean Chemistry.On the earth,the most environonment friendly solvent,is natural infinite recycling of water.It is a cheap,safe,non-polluting green solvent.Theoretically,water as a special solvent,there are hydrophilic and hydrophobic effects.These two effects are related to the change of the enthalpy of the reaction entropy,which can directly promote the reaction.Besides,sulfur compounds exhibit a wide variety of behaviors and have unique functions that make their valuable starting materials suitable for a wide variety of synthetic applications.In particular,as a relatively green sulfur-containing reactant,sulfonylhydrazide has a number of reactive sites and the report of the reactivity in water is rarely reported.According to the aspect mentioned above,we have studied the reactivity of sulfonyl hydrazide in water at different temperatures,combining with the organic reactions in water.And a series of organic reactions based on the construction of sulfur-containing compounds in water were developed.They can be summarized as the following four parts:1.Catalyst-free radical fluorination of sulfonyl hydrazides in waterAt 60 ?,a first catalyst-free fluorination of sulfonyl hydrazides for the synthesis of sulfonyl fluorides has been developed via a free-radical pathway.This protocol presents broad substrate scope and does not require any metal catalyst and additive.All these transformations proceeds smoothly in water under mild conditions,which enables a straightforward,practical and environmentally benign fluorination for S-F bond formation.2.Catalyst-free sulfonylation of activated alkenes for highly efficient synthesis of mono-substituted ethyl sulfones in waterAt 65 ?,a catalyst-free sulfonylation reaction of activated alkenes with sul-fonyl hydrazides was efficiently developed under mild and environ-mentally benign conditions,in water without any ligand or additive.The reaction gave a range of structurally diverse mono-substituted ethyl sulfones with excellent yields,in which the by-product was nitrogen.3.Copper-catalyzed S-methylation of sulfonyl hydrazides with TBHP for the synthesis of methyl sulfones in waterAt 120 ?,a copper-catalyzed S-methylation of sulfonyl hydrazides with TBHP was efficiently developed,providing a variety of methyl sulfones with good to excellent yields.The reaction can be carried out in water smoothly without any ligand or additive under mild conditions and this catalyst-in-water can be recycled several times.4.Catalyst-free thiolation of indoles with sulfonyl hydrazides for the synthesis of 3-sulfenylindoles in waterAt 140 ?,a catalyst-free thiolation of indoles with sulfonyl hydrazides was efficiently developed in water under mild conditions without any ligand or additive.The reaction provided a variety of 3-sulfenyl-indoles with good to excellent yields and the only by-products were nitrogen and water?In addition,through the control experiments,nuclear magnetic and mass spectrometry identification methods,the mechanism of the reaction have been investigated.The reaction intermediates and reactivity of sulfonylhydrazide in water at different temperatures were studied systematically.And sulfides as a kind of important molecules,not only in the present,in the future will get more and better applications.