Lu Hongjian group, School of chemistry and chemical engineering, Nanjing University: visible light promotes the green synthesis of carbazole

Lead carbazole skeleton is a kind of important molecular skeleton widely existing in natural products, drug intermediates and organic photoelectric materials The synthesis of carbazole framework by traditional methods often requires harsh reaction conditions or the use of precious metal catalysts, which greatly reduces the universality and functional group tolerance of the reaction How to synthesize functional carbazole skeleton by simple and green means has been one of the research focuses in organic chemistry Recently, Lu Hongjian group, School of chemistry and chemical engineering, Nanjing University has successfully synthesized functional carbazole molecular framework through visible light promoted intramolecular hydrocarbon bond amination This method has the advantages of mild conditions, high atom economy, no metal catalyst participation, green environmental protection, etc Synthesis of carbazole molecular skeleton (source: green chemistry, 2018, DOI: 10.1039/c7gc03392c) Lu Hongjian's research group was founded in July 2012 At present, the research group has four doctoral students, five master's students and one research assistant The research group has first-class instrument facilities and scientific research conditions, the main research directions are: 1 Metal Catalysis / photocatalysis of hydrogen hydrogen bond amination with azide as nitrogen source; 2 Construction of carbon fluorine bond and its application in pet The research group has extensive exchanges and cooperation with the first-class research groups of famous foreign universities (University of California, burley, Boston University, University of North Carolina, Chapel Hill) It is the backbone research team of the school of chemistry and chemical engineering and the Institute of chemistry and biomedical science of our university The laboratory and lounge of the research group invited famous scholars for academic exchange (experimental facilities: mikrona glove box, Bruker 400MHz NMR, Agilent HPLC, UHD accurate mass Q-TOF, Agilent GC-MS), Lu Hongjian, associate professor, Lu Hongjian, special professor of Jiangsu Province, doctoral supervisor, team leader of "functional organic small molecule synthesis" research group of Nanjing University He graduated from Shanghai Institute of organic chemistry in 2006, and his tutor is Professor Li Chaozhong From 2007 to 2012, he was engaged in postdoctoral research at the University of South Florida In July 2012, he was an associate professor of the school of chemistry and chemical engineering of Nanjing University So far, 12 articles have been published in the top journals of primary chemistry, such as angelw Chem Int ed., J am Chem SOC., etc., and a series of outstanding research results have been achieved With an area of about 200 square meters, it now directs a research team composed of four doctoral students, five postgraduate students, one assistant researcher and several undergraduate students Presided over a general program of NSFC (2015-2018), and participated in a key program of NSFC (2014-2018) as a sub project leader As the chief scientist, he established a scientific research team and presided over the scientific and technological innovation team of "blue and green project" in Jiangsu Province (2014-2017) In 2012, he was hired as "Jiangsu special professor", and in 2015, he was assessed as excellent, and obtained the qualification of "Jiangsu special professor" Brief introduction of Frontier achievements: visible light promotes the green synthesis of carbazole molecules The synthesis of functionalized carbazole skeleton by simple and green methods has been one of the research hotspots in organic chemistry Figure 1: carbazole natural products (source: Green Chemistry) take azide as nitrogen source of hydrocarbon bond amination reaction, which has the advantages of easy preparation, high atomic economy, no oxidation conditions, nitrogen as the only by-product and so on Based on previous studies on C-H bond amination using azide as nitrogen source (angew Chem Int ed 2014, 53, 7028; org Lett 2015, 17, 1513; chem EUR J 2016, 929220; org Lett 2016, 18, 1386; EUR J org Chem 2016, 34, 5611; J org Chem 2016, 81, 4898; chem SCI., 2016, 7, 6934), The synthesis of carbazole skeleton by 2-azido biphenyls under mild conditions was attempted This kind of reaction is an important reaction for the synthesis of the skeleton However, the traditional methods need high temperature or UV / laser radiation and other severe conditions, which not only does not meet the requirements of modern organic green energy saving, but also greatly limits the range of substrate Recently, some research groups have reported the intramolecular amination of hydrocarbon bonds catalyzed by transition metals However, the metal residue in the products is a difficult problem to solve Lu Hongjian's group optimized a series of conditions on the basis of the previous hydrocarbon bond amination reaction It was found that water and visible light could jointly promote the decomposition of 2-azido-biphenyls and thus synthesize carbazole molecular framework The reaction has the advantages of mild conditions, high atom economy, no metal catalyst participation, simple post-treatment and environmental protection Figure 2: Condition Optimization (source: Green Chemistry) based on the best conditions, the author explored the universality of substrate When the aromatic ring contains electron absorption group, electron donor group, ester group, cyano group, carbonyl group, amide, halogen and other common functional groups, the expected products can be obtained in high yield The reaction showed excellent functional group tolerance When the substrate is polyaromatic cycloazide, the reaction can also be carried out well, which shows that the reaction has potential application value in the synthesis of complex polyaromatic cyclocarbazole molecular skeleton Figure 3: substrate expansion (source: Green Chemistry) the author cleverly designed intermolecular competition experiment, intramolecular competition experiment, deuterium experiment, and the results show that azide decomposition is the decisive step of reaction Large scale preparation experiments show that the reaction has potential application value This method has been applied to the synthesis of natural products, and a series of natural products have been synthesized concisely At the same time, it has been proved that acid and alkali buffer can be used as reaction solvent, which lays a foundation for the full synthesis of natural products and the potential application of chemical biology Figure 4: natural product synthesis (source: greenchemistry) Figure 5: reaction in acid / alkaline buffer solution, amplification reaction and post-treatment simplification (source: Green Chemistry) The research results were published on green chemistry, and Yang Lizheng, a master's degree student of Nanjing University, was the first author of the paper The research work was supported by the National Natural Science Foundation of China (No 21332505, 21472085) and the basic research business expenses of the Central University (No 020514380114) Paper link: http://pubs.rsc.org/en/content/articlelanding/2018/gc/c7gc03392c ා! Divabstract Lu Hongjian research group home page: http://hysz.nju.edu.cn/luhj/research.html about people and scientific research getting more and more attention in economic life, China welcomes the "node of science and technology explosion" Behind the progress of science and technology is the work of countless scientists In the field of chemistry, in the context of the pursuit of innovation driven, international cooperation has been strengthened, the influence of Returned Scholars in the field of R & D has become increasingly prominent, and many excellent research groups have emerged in China For this reason, CBG information adopts the 1 + X reporting mechanism CBG information, chembeango app, chembeango official microblog, CBG wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the domestic representative research group, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.