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    Home > Han Jianwei and Wang Limin, East China University of science and technology: palladium catalyzed series reaction of benzimidazo [1,2-α] pyridine derivatives to construct fused ring compounds

    Han Jianwei and Wang Limin, East China University of science and technology: palladium catalyzed series reaction of benzimidazo [1,2-α] pyridine derivatives to construct fused ring compounds

    • Last Update: 2019-05-05
    • Source: Internet
    • Author: User
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    Lead organic conjugated polycyclic aromatic hydrocarbons and polycyclic heteroatom aromatic hydrocarbons are the matrix of advanced functional molecular modification and the material science foundation of electronic information technology The development of functional molecular directed synthesis methodology has been a hot field in organic chemistry In recent years, more and more attention has been paid to the transition metal catalyzed hydrocarbon activation of diaryldinium salts However, it is quite challenging to activate the C-I bond and o-i-c bond of diaryldinium salts simultaneously and to construct the fused aromatic hydrocarbons by one-step bonding Based on the previous work, Han Jianwei and Wang Limin of East China University of science and technology developed the polyarylation reaction with diaryl iodide in acetic acid solvent with 2-phenylimidazo [1,2-α] pyridine as the substrate, forming three C (SP 2) - C (SP 2) bonds in one pot In this method, phenanthrene [9 ', 10': 4,5] imidazo [1,2 - α] pyridines were prepared efficiently and conveniently These compounds have strong fluorescence effect and are potential organic luminescent materials The results were published in org Lett (DOI: 10.1021 / ACS Orglett 9b00761), an academic journal of the American Chemical Society Brief introduction of Han Jianwei and Wang Limin research groups Han Jianwei and Wang Limin have been devoted to the study of aromatization methodology and asymmetric catalytic chemistry of high valent iodine chemistry for many years (Asian J org Chem 2012, 1, 218; org Lett 2015, 17, 5654; J org Chem 2016, 81, 1317; adv synth Catalyst 2016, 358, 940; J org Chem 2018, 83 , 49; Angew Chem Int Ed 2018 , 57 , 12313 )。 The research group expects to build a "new method of organic synthesis - Study on the properties of conjugated molecules" system based on a new method of reaction involving high valent iodine, characterized by benzoaromatization and polyarylation, and aimed at the synthesis of functional conjugated small molecular optoelectronic materials On the basis of the system, the research group expects to make contributions to the field of synthesis of new fine chemicals, such as dyes, pigments, pesticides, and the practical application of new drugs and advanced functional small molecular materials Han Jianwei, associate professor, Department of fine chemistry, School of chemistry and molecular engineering, East China University of science and technology From February to July 2005, he was a research fellow of new drug research and development in Shanghai yaomingkant company In 2009, he received his doctor's degree in Natural Science (Dr RER NAT.) from RWTH Aachen University of technology, Germany, under the guidance of Professor Dieter Enders From 2009 to 2011, he was engaged in postdoctoral research in the research group of Professor Keiji maruoka of Kyoto University, Japan From May 2011 to November 2016, he served as an associate researcher in the research team of academician Huang naizheng of Shanghai Hong Kong joint Synthesis Laboratory of Shanghai Institute of organic chemistry, Chinese Academy of Sciences Since November 2016, he has served as an associate professor in the Department of fine chemistry, School of chemistry and molecular engineering, East China University of science and technology So far, he has published more than 50 research papers in international academic journals He has won the outstanding research achievement award of Shanghai in 2007, the highest citation rate award of tetrahedron magazine in 2005-2008, and Thieme Chemistry Journals award in 2014 Main research interests: design the application of new catalysts in asymmetric catalysis, explore new reactive synthesis functional molecules and sustained release of aroma and controlled release of harmful organic volatiles (VOC) Introduction to Professor Wang Limin, Professor of Fine Chemical Engineering Department, School of chemistry and molecular engineering, East China University of science and technology, leader of the tutor group of master's program of light industry technology and engineering, and tutor of "good job in China", as the main speaker of the course of chemistry and art He has obtained a doctor's degree in Applied Chemistry (Fine Chemistry) from Dalian University of technology and visited Cornell University as a visiting scholar He is also a member of the American Chemical Society, the fine chemical Committee of the Chinese chemical society, and the expert group of the national rare earth dyeing and tanning cooperation network Served as the editorial board member of Applied Chemistry, fine chemicals and China leather So far, more than 50 papers have been published in international core journals such as J org Chem., adv synth Catalyst Among them, articles published in tetrahedron (Tetrahedron 2005, 61, 1539-1543) in 2005 were awarded tetrahedron most cited paper 2005-2008 award 37 Chinese invention patents have been applied for, 16 of which have been authorized Publishing 6 related works (including co editing or co translation) He has won Shanghai Science and technology award, Shanghai Technology Invention Award, Ministry of Education Technology Invention Award, Ministry of Education Technology Progress Award and other awards Leading scientific research achievements: palladium catalyzed series reaction of phenyl imidazo [1,2-α] pyridine derivatives to construct fused ring compounds In recent years, in the field of organic synthesis, high valent iodine compounds have attracted much attention due to their mild, non-toxic and high selectivity As a kind of high valence iodine compound, diaryl iodide is often used as an efficient arylation reagent However, many of the reported reactions are limited to the activation of C-I bond, while the double activation of C-I bond and o-i-h bond is relatively rare Therefore, the double activation strategy provides a great possibility for the construction of fused ring compounds in one step In 2015, with coumarin as the raw material, the research team developed a one pot method to synthesize 4,5-benzocoumarins under the action of palladium catalyst, thus complementing the benzocoumarin family (Fig 1, org Lett 2015, 17, 5654) In the following work, the benzoaromatization of 2-bromobiphenyls with diaryldiiodates was realized, and a series of 9,10-benzophenanthrene like polycyclic aromatic hydrocarbons were synthesized (Fig 2, J org Chem., 2018, 83, 49-56) Fig 1 One step synthesis of 4,5-benzocoumarin by double activation strategy (org Lett., 2015, 17, 5654 − 5657) Fig 2 One step synthesis of 9,10-benzophenanthrene-like polycyclic aromatic hydrocarbons by double activation strategy (J.Org Chem., 2018, 83, 49-56) Under the guidance of the same strategy, the author first used 2-phenylimidazo [1, 2-α] pyridine 1a and diphenyliodonium trifluoromethylsulfonate 2A were used as raw materials to optimize the reaction conditions The results showed that the target compound phenanthrene [9 ', 10': 4,5] imidazo [1,2 - α] pyridine was obtained in 83% yield under the optimal conditions In order to investigate the substrate application scope of this method, the author investigated a series of 2-phenylimidazo [1,2-α] pyridine (Fig 3) and diphenyliodonium trifluoromethylsulfonate (Fig 4) containing different substituents, all of which obtained the target product in medium to good yield Figure 3 2-phenylimidazo [1, The substrate expansion of 2-α] pyridine (source: org Lett Doi: 10.1021 / ACS Orglett 9b00761) Fig 4 The substrate expansion of diaryl iodide (source: org Lett Doi: 10.1021 / ACS Orglett 9b00761) Then, the author conducted a series of control experiments to explore the bonding sequence of three C (SP 2) - C (SP 2) bonds (Fig 5) Figure 5 Control experiment (source: org Lett Doi: 10.1021/acs.orglett.9b00761) Finally, according to the control experiment, the author proposed the possible reaction mechanism (Figure 6) First of all, under the action of acetic acid, 1 a forms imidazolium salt of acetate anion, which weakens the activity of position 3 In addition, the steric hindrance of acetate anion is also the reason of C-H bond passivation of position 3 Then, the electrophilic insertion of palladium formed a five element palladium intermediate, and a new C-C bond was formed under the action of iodized salt Another symmetric C-C bond was constructed by rotating the intermediate Finally, the intermediate was cross dehydrogenated and coupled to obtain the target product Fig 6 Possible reaction mechanism (source: org Lett Doi: 10.1021 / ACS Orglett 9b00761) To sum up, the author developed a series reaction of diaryldium salt participated in the diaryl / cross dehydrogenation coupling of 2-phenylimidazo [1,2-α] pyridine derivatives under palladium catalysis, so as to construct phenanthrene [9 ', 10': 4,5] imidazo [1, 2-α] pyridine, a kind of fused ring compound, has excellent yield and substrate applicability This achievement was recently published in org Lett (DOI: 10.1021/acs.orglett 9b00761) The corresponding authors are Professor Han Jianwei and Professor Wang Limin The above research work was supported by the national key research and development program, the National Natural Science Foundation and the Hong Kong Qiucha foundation Nowadays, people and scientific research have been paid more and more attention in the economic life China has ushered in 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, chembeangoapp, 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.
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