Fluoroalkylthiolation Reactions With Sulfur And Synthesis Of Sulfur-containing Compounds By The Three-component Cascade Reaction

In recent years,organic fluorinated compounds are widely used in medicine,agriculture,chemistry,and materials.In particular,sulfur and fluorine-containing groups(SCF₂H and SCF₃)can effectively change the biological activity of drug molecules,and show potentialsfor drug development and research.Sulfur is one of the most important raw materials of the modern chemical industry.Sulfur is usually present in the form of S₈.However,the S–S bond homolytic scission occurs upon heating,leading to S_n radicals.The allotropes are found to be more reactive than S₈ and thus used to synthesize sulfur-containing compounds.Therefore,introduction of a“SCFn(n=1-3)”moiety to an organic molecule by using of elemental sulfur as the sulfur sourse would be the most efficient and economic route of fluoroalkylthiolation reactions.This doctoral dissertation mainly includes:Chapter 1.The recent progresses of fluoroalkylthiolation reaction and the synthesis of sulfur-containing compounds with sulfur are reviewed.Chapter 2.We have developed a three-component tandem reaction of o-hydroxy chalconone derivatives,sodium difluorochloroacetate,and sulfur under the action of base.This reaction has the advantages of cheap raw materials,mild reaction conditions,wide scope of substrates,and simple operation.It provides a practical and efficient method for the synthesis of3-HCF₂S-chromones derivatives.Chapter 3.We studied the three-component tandem cyclization reactions of2-acetylaminochalones,sodium difluorochloroacetate,and sulfur under basic conditions.The reaction may proceed via intramolecular addition of amide radical with olefin and nucleophilic addition of carbon anion with an acetamide group.This method has the advantages of mild conditions,no need of inert gas protection,wide scope of substrates,and high atom-economy,which provides an important way for the synthesis of cyclic difluoromethyl thioether indoline derivatives.Chapter 4.We developed a three-component tandem reaction of amine,olefin and sulfur without metal catalysis to selectively synthesize two thioamide derivatives by controlling different bases.ESI-MS was used to analyze the key intermediates in reactionprogress.This reaction has the advantages of good functional group tolerance,mild reaction conditions,simple operation,which shows potential application values in the synthesis of thioamide-containing bioactive molecules and drugs.Chapter 5.We developed an efficient palladium-catalyzed approach to the synthesis of functionalized benzo[d]oxazoles derivatives via sequential heteroarylation/acylation reaction of iodobenzenes.The reaction process mainly includes palladium catalyzed C-I bond and C-H bond activation to construct two C-C bonds.It provides a new method for the synthesis of heterocyclic compounds showing potential application in the synthesis of natural products,drugs and materials.