Study On The Development Of Novel Synthetic Methodsbased On The Diverse Reactivity Of Vinyl Azides

Vinyl azides are highly attractive synthetic intermediates owing to their unique structural characteristics and diverse reaction patterns.Meanwhile,N-heterocyclic scaffolds,trifluoromethyl group and amide unit are core components of a plethora of clinical drugs,pesticides and natural products.Therefore,their efficient introduction and construction constitute important topics in the field of organic synthesis.Based on the above mentioned background,some coupling and condensation reactions ofvinyl azides were designed and implemented in this thesis.Through these reactions,some efficient and novel methods for the preparation of trifluoroethylphenanthridine and ?-amidoketone derivatives were developed.The main content of thisthesis can be divided into the following two parts:In the first part,the one-pot three-component cascade reaction of vinyl azide with cyclic ?-carbonyldiazo compound and Togni's reagent was studied.From this reaction,a series of trifluoroethylphenanthridine and benzochromone derivatives were efficiently synthesized in a one-pot manner.In these reactions,Togni's reagent not only participated in the formation of trifluoroethylphenanthridine by providing a trifluoromethyl radical,but also took part in the formation of benzochromone by providing o-iodobenzoic acid.It is worth to note herein that,to the best of our knowledge,this is the first example in whichthe by-product of Togni's reagent,o-iodobenzoic acid,was captured in situ to form valuable product instead of being abandoned as a waste.In the second part,the condensation reaction between vinyl azide and carboxylic acid was studied.From this reaction,a series of ?-amidoketone derivatives were efficiently synthesized.Preliminary mechanistic studies showed that the formation of the title compounds should involve the nucleophilic attack of carboxylic acid onto vinyl azide to form an aziridine intermediate followed by its thermal rearrangement.It is worth to emphasize herein that this is the first example in which ?-amidoketone derivatives were synthesized starting from vinyl azide in the absence of any catalyst.In summary,some novel and efficient methods for the preparation of trifluoroethyl phenanthridine and ?-amidoketone derivatives by usingvinyl azides as versatile substrates have been successfully developed.Compared with literature methods,these new methods have the advantages of mild reaction conditions,high atom-economy and wide range of substrates.