Construction Of Novel N-heterocycles Via Tert-amino Effect

Nitrogen-containing heterocycles are widely found in natural products,and a variety of N-heterocyclic compounds are used in the fields of medicinal chemistry,dye chemistry,botanical pesticides,and daily chemicals.Therefore,the construction of N-heterocycles through simple,efficient and environmentally-friendly method is considered as an important subject in the field of organic and pharmaceutical chemistry.Tert-amino effect is an efficient synthetic tool for the construction of nitrogen-containing heterocyclic compounds.Synthsis of complicated nitrogen-containing heterocycles could be easily realized via the tert-amino effect,which has attracted considerable interest from the researchers.During the past few years,a series of N-heterocyclic compounds were synthesized based on these reactions,including five-membered,six-membered,seven-membered,and medium/large-sized N-heterocycles.But these methods could not completely satisfy the synthesis requirement of the complex and diverse N-containing structures.On the other hand,rencent research of these reactions was focused on the classical [1,n]-hydride transfer.Defects of these [1,n]-hydride transfer reactions,such as the limited product structure,result in some limitation in the use of tert-amino effect.Therefore,development of new reactions,extension of the substrate range,construction of novel N-heterocycles based on tert-amino effect remain a great challenge to researchers.In this thesis,based on tert-amino effect,a series of novel N-heterocycles was constructed through reasonable design of substrate and special use of novel electrophilic receptors.A novel intramolecular nucleophilic addition/rearrangement cascade using tert-amino substituted phenylisothiocyanate as reactant was developed,and construction of benzimidazo[1,3]thiazepine and benzimidazothioether motifs was realized based on the tert-amino effect.The reaction was catalyzed by low-cost camphorsulfonic acid and tolerated broadly in scopes with high atom economy.More than twenty desired products were obtained in high yield.The product was characterized by NMR,HRMS,X-ray crystallography etc.At last,a plausible mechanism of the reaction was proposed;the practical utility was verified via gram scale synthesis and transformation of the product.