Study On Oxidative Coupling Reaction Of Vinyl Azides With 2-arylhydrazines Or Aldehydes

Vinyl azides,a kind of bifunctional organic synthons,not only can participate in the special reactions of azide,but also act as electrophile reagent,nucleophile reagent and radical receptors in organic reactions.The history of vinyl azides as radical receptors can be traced back to the 1970s.Iminyl radical is the key intermediate of radical oxidative coupling reaction of vinyl azides,which can be used to construct chemical bonds such as C-C,C-N,C-S,C-O and C-P bonds,and synthesis of carbonyl,enaminone or enamine sulfone,nitrogen-containing heterocyclic compounds.These compounds are highly versatile and attractive intermediates employed in the preparation of various organic constructions and pharmaceutical targets.Based on the multiple reactivities of vinyl azides,we developed the study of the coupling reaction of vinyl azides as radical receptors to synthesize a series of 2-arylacetophenones andβ-Enaminones.The thesis is divided into three chapters.Chapter 1.IntroductionThe chapter summarize the oxidative coupling reaction of vinyl azides as radical receptors to synthesize carbonyl,enamine and nitrogen-containing heterocyclic compounds.To further understand the possible intermediates and mechanism of the type of reactions.Chapter 2.H₂O₂-mediated room temperature synthesis of 2-arylacetophenones from arylhydrazines and vinyl azides in waterAn environmentally benign,cost-efficient and practical methodology for the room temperature synthesis of 2-arylacetophenones in water has been discovered.The facile and efficient transformation involves the oxidative radical addition of arylhydrazines withα-aryl vinyl azides in the presence of 4.0 equiv.H₂O₂（as a radical initiator）and 5mol%PEG-800（as a phase-transfer catalyst）,which desired product with the yield of74%-90%,and amenability to gram-scale synthesis.From the viewpoint of green chemistry and organic synthesis,the present protocol is of great significance because of using cheap,non-toxic,readily available starting materials and reagent,as well as eco-friendly reaction solvent.Chapter 3.CuCl₂·2H₂O/TBHP mediated synthesis ofβ-enaminones via coupling reaction of vinyl azides with aldehydesA facile and efficient oxidative cross-coupling reaction of vinyl azides with aldehydes was developed,as well as the new C-C and C-N bonds were formed via a one-pot strategy.The reaction of aldehydes andα-phenyl vinyl azides with 5 mol%CuCl₂·2H₂O as a catalyst and 4.0 equiv.TBHP as an oxidant in DMSO at 80℃.Aldehydes were promoted to produce acyl radicals in the condition and obtain（Z）-β-acylated enaminones with the yield of 61%-89%by the process of radical addition and recombination.