| Sulfur compounds are widely present in daily life.The multivalent sulfur brings the richness of organic sulfide structures.Because of its special physical and chemical properties,organic sulfides are widely used in the fields of organic synthesis,material chemistry,medicine,perfume,etc..For a long time,organic chemists have been paying much attention to the construction method of C-S bonds.There have been many related reports on the construction of C-S bonds under transition-metal catalysis,but the method of building C-S bonds without transition-metal catalysis still needs further exploration.In recent years,aryl sulfides as radical precursors,free radical-mediated enynes tandem cyclization reactions have attracted widespread attention.Although electron-rich enynes,such as 1,n-enyne amide substrates,are often used as free radical acceptors in these reactions,the application of electron-deficient enynes in this filed is still a huge challenge,especially in tandem cyclization reactions.This thesis mainly studies the regioselective tandem cyclization reaction of 1,6-enynes with sulfide radicals.The main research contents are as follows: First,the initiation conditions of sulfur free radicals.The sulfur free radicals can be obtained at 90°C through p-methylthiophenol with AIBN.Then the reactions of sulfur free radicals with 1,6-enyne substrates were carried out,and sulfur-containing five-membered nitrogen heterocyclic products are obtained.Subsequently,we optimized the reaction conditions for this tandem cyclization reaction of sulfur radicals and 1,6-enyne substrates,such as the amount of sulfur source,solvent,atmosphere conditions,etc.,and through the reaction time and reaction yields indicators to determine the best reaction conditions.Next,we study the substrate scopes of this reaction,herein,we designed and synthesized representative substrates to explore the tolerance of reaction substrates and the influence of various functional groups for this reaction. |
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