Synthesis And Reactivity Of Novel Nitrogen-Containing Hypervalent Iodine Reagents

The application of organic compounds to drugs,pesticides and materials has a profound impact on our daily life,and the development of new chemical tranformations is the core of synthetic organic chemistry.Due to its advantages of high reactivity and environmentally benign,hypervalent iodine reagents have been increasingly used in the field of organic synthesis.In recent years,organic iodine(?)reagents,especially benziodoxole compounds,as a kind of functional group transfer reagents,can introduce groups such as trifluoromethyl,alkynyl,azide and aryl into substrate molecules.Carbzaoles are privileged scaffolds in various natural products,pharmaceutical agents,and functional materials.Carbazole alkaloids are widely found in plants and have a wide range of biological acthivities,such as anti-cancer,antimicrobial,and antiinflammatory.Carbazole-based materials have been studied in the field of organic lightemitting devices(OLEDs)and solar cells for their unique optical and electrochemical properties.We first synthesized a class of carbazole-containing cyclic hypervalent iodine reagents,these reagents belong to the benziodoxole derivatives.The reactivity of these reagents were also studied,which proved that it can be used as a kind of functional group transfer reagents to introduce carbazolyl into substrate molecules.Our work is mainly divided into two parts:In the first part,we explored the synthesis route of carbazole-containing cyclic hypervalent iodine reagents.Starting from carbazole and 2-iodobenzoic acid,a series of air-stable carbazole-containing cyclic hypervalent iodine reagents were successfully synthesized.And the structure of the products is confirmed by 1H NMR,13C NMR and XRD analysis.In the second part,the coupling reaction between aromatic substrate and carbazole was achieved by using carbazole-containing hypervalent iodine reagents,catalyzed by copper salt and acetonitrile as solvent under heating condition.Different from the traditional C-N coupling reaction,N-arylated carbazoles derivatives can be obtained by this method without pre-activated substrates and harsh reaction conditions.The reaction is suitable for electron-rich thiophene derivatives and simple arene substrates.Finally,we conducted a preliminary study of the reaction mechanism and proposed a plausible radical mechanism.