Construction Of Alkenyl Sulfides And Thiophene Rings By Using Elemental Sulfur As Sulfur Source

Sulfur-containing organic compounds are widely present in various natural products and organic functional molecules.The construction of carbon-sulfur bonds has always been an important part of organic synthesis.In this thesis,alkenyl sulfide compounds and thiophene derivatives were synthesized from alkynyl ketones by using elemental sulfur as sulfur source.The main research contents are as follows:1.Synthesise of alkenyl sulfide compounds by copper catalyzed reaction of alkynyl ketones,iodobenzene and elemental sulfur.The three-component reaction of alkynyl ketone,iodobenzene and elemental sulfur was investigated.The reaction conditions such as temperature,catalyst,base and solvent were optimized,and the substrate adaptability was probed.A series of 2,3-dithioalkenyl ketone compounds was obtained in up to 92%yield.The three-component reaction of alkynyl ketones,elemental sulfur and1,2-diiodobenzene was further investigated,and a series of 1,4-dithiohexacyclic compounds were synthesized in up to 93%yield.The reaction has advantages such as the use of odorless and stable elemental sulfur as sulfur source,high stereoselectivity and simple operation.All the products were characterized by ¹H NMR,¹³C NMR and HR MS.The molecular structure of compound（Z）-1-（p-methoxyphenyl）-3-phenyl-2,3-bis（p-methylphenylthio）propane-2-yn-1-one was confirmed by X-Ray diffraction analysis,and the result shows that the cis-addition reaction of alkynyl ketone was happened.2.Synthesis of indanono[1,2-c]thiophene compounds by reaction of 1,6-diyn-3-ones and elemental sulfur.The base-promoted reaction of 1,6-diyn-3-ones and elemental sulfur was investigated.The reactions conditions such as base,solvent,equivalent ratio of reactants,and temperature were optimized,and the adaptability of the substrate scope was probed.A series of differently substituted indanono[1,2-c]thiophene compounds were synthesized in up to 87%yield.The reaction has advantages such as the use of odorless,and stable elemental sulfur as sulfur source,metal catalyst-free,simple operation and good substrate adaptability.The research results provide a new method for the synthesis of polycyclic thiophene derivatives.The preliminary studies on the reaction machanism shown that the reaction may proceeded via a radical intermediate.All the products were characterized by ¹H NMR,¹³C NMR and HR MS.