Chen Jiuxi research group, Wenzhou University: palladium catalyzed series reaction of o-cyano-biaryl compounds with aromatic boric acid to synthesize diaryl-p [C, e] acroheptides

Introduction Chen Jiuxi research group, School of chemistry and materials engineering, Wenzhou University has long been committed to the study of transition metal catalyzed organoboron reactions Recently, the research group has made new progress in this field: palladium catalyzed synthesis of 5-arylmethylene-7-aryl-5h-diaryl-p [C, e] acroheptine (DOI: 10.1021 / ACS Orglett 9b02351) from o-cyanodiaryl compounds and arylboric acid in series Chen Jiuxi research group is mainly engaged in the study of transition metal catalyzed reaction of organoboron reagents with nitriles, and is committed to developing novel organic synthesis methods and strategies to construct a series of nitrogen-containing heterocyclic compounds At the same time, the research group has also carried out research on nitrogen-containing heterocyclic compounds and pharmaceutical chemistry Welcome students who love organic chemistry and pharmaceutical chemistry to join the research team Introduction to Dr Chen Jiuxi: Chen Jiuxi, special professor of Oujiang, Wenzhou University, tutor of master's degree, top young talents of "ten thousand talents plan" in Zhejiang Province In 2004, he graduated from the Department of chemistry of Wenzhou Normal University (now the school of chemistry and materials engineering of Wenzhou University), obtained the master's degree of Wenzhou University in 2007, obtained the doctor's degree of Zhejiang University of technology in 2014, and has worked in Wenzhou University since September 2007 Up to now, he has published more than 80 SCI papers in the journals of org Lett., C hem Commun., J org Chem., green chem., adv synth Catalyst He has authorized more than 30 invention patents, won the third prize of Zhejiang science and Technology Award (ranking first) and excellent project of Zhejiang Science Foundation (ranking first) in the 11th five year plan Frontier research achievements: palladium catalyzed series reaction of o-cyano-bipararyl compounds with aromatic boric acid to synthesize diarylphenyl [C, e] heptane and its derivatives are important nitrogen-containing seven membered heterocyclic compounds However, the construction of dibenzo [C, e] heptane skeleton has always been a challenging topic in organic synthesis chemistry At present, there are few reports on the synthesis of dibenzo [C, e] heptane derivatives Inspired by the previous work of the research group on palladium catalyzed series reaction of nitriles and arylboric acid (org Lett 2017, 19, 218; greenchem 2017, 19, 1740; org Lett 2018, 20, 3083; adv synth Catalyst 2018, 360, 3260), the author uses the 2 '- acetyl - [1, The series reaction of 1 '- biaryl] - 2-nitriles with aryl boric acid has realized the synthesis of 5-arylmethylene-7-aryl-5h-diaryl [C, e] acrheptyl derivatives which are difficult to be prepared by traditional methods Fig 1 Synthesis of 5-arylmethylene-7-aryl-5h-diaryl-heptane [C, e] acridine (source: org Lett.) by cross ring series reaction, the author has carried out a series of screening of reaction conditions, and finally determined the following reaction conditions: palladium trifluoroacetate as catalyst, 2,2 '- bipyridine as ligand, methanesulfonic acid as additive, n, When n - dimethylformamide was used as solvent, the yield of the target product was the best The results show that all kinds of substituted 2 '- acetyl - [1,1' - biphenyl] - 2-nitriles and arylboric acid can obtain the target products in medium to good yields Fig 2 Arylboric acid substrate development (source: org Lett.) Fig 3 2 '- acetyl - [1,1' - biphenyl] - 2-nitrile substrate development (source: org Lett.) in addition, the author further confirmed the structure of product 3j by X-ray crystal diffraction, as shown in the figure below Figure 4 Structure of product 3j (source: org Lett.) in order to further study the possible mechanism of the series reaction, the following control experiments were designed and DFT theoretical calculation was carried out (Figure 5) Fig 5 Control experiment and DFT theoretical calculation (source: org Lett.) based on the above experiment and calculation results, the author proposed the possible reaction mechanism: firstly, palladium catalyst a and arylboric acid form aryl palladium species B through transfer metallization, then cyano in 2 '- acetyl - [1,1' - biaryl] - 2-nitrile coordinate with palladium and form imine through carbon palladization- Palladium intermediate C; then intermediate C undergoes intramolecular cyclization to obtain palladium compound D; in the presence of msoh, D is protonated to generate alcohol intermediate e, and palladium catalyst is regenerated; alcohol intermediate e undergoes dehydration to obtain olefin intermediate f; finally, F and arylboric acid undergoes oxidation heck coupling reaction to obtain target product 5-arylmethylene-7-aryl-5h- Diaryl and [C, e] heptane derivatives Figure 6 Possible reaction mechanism (source: org Lett.) the research results are published in org Lett (DOI: 10.1021/acs.orglett 9b02351) The first author of this paper is Yao Xinrong, 2017 master of Wenzhou University, and Shao Yinlin of the research group is the co first author The research is assisted by other graduate students and teachers of the research group The theoretical calculation part was completed by Professor Xia Yuanzhi of Wenzhou University, and the corresponding author was Professor Chen Jiuxi The research work was supported by NSFC (21572162) and Zhejiang Natural Science Foundation (ly16b020012, lq18b020006) Today, when Yao Xinrong (left) and Shao Yinlin (right) pay more and more attention to figures and scientific research in the economic life, China has ushered in the "node of the outbreak of science and technology" 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 website, chembeangoapp, chembeango official micro blog, CBG information wechat subscription number and other platforms jointly launch the column of "people and scientific research", approach the representative research groups in China, pay attention to their research, listen to their stories, record their demeanor, and explore their scientific research spirit.