Radical Cyclization Of Tert-Butyl Nitrite For The Synthesis Of Nitrogen-containing Heterocyclic Compounds

Nitrogen heterocycles are important and highly useful structures scaffolds and are widely found in natural products.More importantly,they are also widely applied in medicines,pesticides,industries,and multifunctional materials.Nitrogen heterocycles,especially multi-sulfonyl-functionalized nitrogen heterocycles,play an important role in medicinal chemistry due to their unique biological activity.Thus,development of powerful and practical methods for producing these nitrogen heterocycles are very attractive.Based on the analysis of the research progress of such reactions,combined with the research direction of this research group,this paper has developed a series of simple and efficient methods for constructing sulfonyl-containing three or five-membered nitrogen heterocyclic compounds,which enriches 2,2-disulfonyl-2H-aziridine and sulfonyl isoxazole compounds.The research content of this thesis mainly focuses on the following three aspects:(1)The first chapter of the paper gives a detailed description on the research of sulfonyl or nitrogen-containing heterocyclic compounds in recent years,which is mainly divided into two aspects:(I)Research progress of nitrogen-containing heterocyclic compounds;(II)Research progress of sulfonyl-containing compounds.(2)The second chapter describes a three-component metal-free oxidative decarboxylation method for efficient synthesis of 2,2-disulfonyl-2H-aziridine.tertButyl nitrite is used as a nitrogen source,and sodium sulfinate is used as a free radical source to initiate the reaction.All kinds of aryl carboxylic acids can be used to obtain the target product in a moderately high yield.The reaction has the advantages of mild conditions,metal-free catalysis,and little by-products.Control experiment results showed that the reaction goes through a free radical pathway.(3)The third chapter describes a three-component 1,3,4-trifunctional tandem reaction of 1,3-enyne,tert-butyl nitrite and sodium sulfinate promoted by indium to construct a series of 5-sulfonyl isoxazoles.The reaction goes through a free radical process,in which tert-butyl nitrite acts as a free radical initiator and also provides two atomic units of nitrogen and oxygen in the [3+2] cyclization process.The reaction generates three new carbon-heteroatom bonds,namely C-S,C-N,and C-O bonds.The reaction has a wide range of substrates and excellent adaptability.The 1,3,4-trifunctional tandem reaction provides an effective way for the formation of carbonheteroatom bonds,construction of isoxazole skeletons with high application value,and late modification of natural products.