Study On The Construction Of Sulfur-and Nitrogen-Containing Seven-Membered Heterocyclic Compounds

This thesis mainly consists of four chapters:(1)application and research progress of versatile sulfur-and nitrogen-containing synthons;(2)study on the reaction of zwitterionic thiolates with vinylidene ortho-quinone methide;(3)study on the reaction of N,N'-cyclic azomethine imines with 1,3,5-triazinanes.Chapter 1: application and research progress of versatile sulfur-and nitrogen-containing synthonsSulfur-and nitrogen-containing heterocyclic compounds are widely existed in nature as the skeleton structure of biologically active substances(such as vitamins,hormones,alkaloids)and many natural products.Furthermore,they have important applications in medicine,agriculture,industry and materials.Sulfur-and nitrogen-based synthons provide a series of simple and efficient synthetic approaches.In this chapter,the researches on the reactions involving two types of synthons,zwitterionic thiolates and 1,3,5-triazinanes,are mainly introduced.Chapter 2: study on the reaction of vinylidene o-quinone methide with1,4-zwitterionic thiolatesThe synthesis of naphthalene-fused 1,4-oxathiepines from pyridinium1,4-zwitterionic thiolates with ?-alkynylnaphthalen-2-ols has been achieved under mild conditions in excellent yields.The in situ generated vinylidene ortho-quinone methide is the key reactive intermediate.In addition,the substrate range can be extended from common-used ?-alkynylnaphthalen-2-ols to 2-phenylethynylphenol modified with strong electron-donating substituents,and the corresponding mechanism was verified by computational chemistry.Finally,the catalytic asymmetric version of this(4 + 3)reaction was further attempted,delivering a unique axially chiral arene-acyclic alkene scaffold bearing a seven-membered 1,4-oxathiepine ring.Chapter 3: study on the reaction of vinylidene o-quinone methide with1,4-zwitterionic thiolatesThe synthesis of pyrazolotetrazepin-7-ones from 1,3,5-triazinanes with N,N'-cyclic azomethine imines was achieved via a formal(5 + 2)pathway under thermal conditions,where five atoms of 1,3,5-triazinanes were incorporated into target molecules.This novel annulation reaction is catalyst-free and additive-free.