Peng Bo group of Zhejiang Normal University: dearylation of aryl high valent iodine

The aromatics which are easy to get can be directly transformed into aliphatic carbon compounds with higher added value by the lead dearylation Therefore, this kind of reaction usually has a high step economy, and becomes an irreplaceable synthesis method in complex molecular synthesis Although great progress has been made in this field, it is still a challenge to establish a new model of dearylation reaction Recently, the team of Peng Bo of Zhejiang Normal University realized the dearylation of aryl high valent iodine by rearrangement reaction, and constructed a new dearylation reaction model Relevant results were published online in angew Chem Int ed (DOI: 10.1002 / anie 201909019) Brief introduction of pembo research group since its establishment, the research group has been engaged in the selective transformation of highly active organic intermediates Recently, the research group has made progress in aromatics rearrangement chemistry, and established a "assembly / deproton" rearrangement model At present, the research group has published more than 20 papers in internationally renowned academic journals, including J am Chem SOC., angelw Chem Int ed and other internationally renowned journals At present, the research group has 2 lecturers and 12 masters Home page of the research group: http://sky.zjnu.edu.cn/2014/0127/c48553a85463/page.htm profile of Professor Peng Bo, Professor of School of chemistry and Life Sciences, Zhejiang Normal University, and project leader Graduated from Nanjing University of technology in 2004 From 2004 to 2010, he studied for a doctor's degree at Dalian University of Technology (Tutor: Professor Bao Ming) From 2011 to 2014, he successively worked as a postdoctoral researcher in Mapu Coal Research Institute of Germany and University of Illinois at Urbana Champaign In 2015, he was employed as a professor by Zhejiang Normal University In the same year, he was selected as a distinguished professor of "Qianjiang scholars" in Zhejiang Province, the first level of Zhejiang new century 151 talent project in 2016, the "academician pairing training young talents plan" in 2018, and the Zhejiang outstanding youth fund in 2019 Frontier research achievements: dearomatization of aryl high valent iodine and its bifunctional reaction diagram 1 Research assumption (EQ 1), preliminary work (EQ 2) and preliminary exploration (EQ 3) (source: angelw Chem Int ed.) in recent years, Peng Bo group of Zhejiang Normal University has focused on aromatics σ The "tension acceleration effect" and "fluorine effect" in the rearrangement reaction were found With the help of these two effects, the research group has developed various types of aromatics σ rearrangement reactions (J am Chem SOC 2017, 139, 4211; angelw Chem Int ed 2018, 57, 9078; angelw Chem Int ed 2019, 58, 5316; angelw Chem Int ed 2019, 58, 5956) Inspired by the above research, the research team designed a new process of dearylation via "rearrangement / addition" (Figure 1, EQ1): the first nucleophile (nu1) was rearranged with aryl high valent iodine to construct the intermediate I of dearylation, and then the second nucleophile (nu2) was introduced to capture the intermediate I The products of biarylation and dearylation are given, which can realize the dearylation of aryl high valent iodine However, the following conditions must be met to realize this assumption: (1) the rearrangement step must be carried out at low temperature and fast speed, otherwise it will face the risk of decomposition of the intermediate I of dearylation; (2) the first nucleophilic reagent (nu 1) for rearrangement can react with the high valence iodine of electrophilicity at high speed, but at the same time, the intermediate I of dearylation with the same electrophilicity must be There is no activity; (3) the first nucleophilic reagent (nu1) must be a functional group with high synthesis value Previously, the team developed the [3,3] - σ rearrangement reaction between aryl high valent iodine and α - tin nitriles (Fig 1, EQ 2) (angelw Chem Int ed 2018, 57, 9078) The rearrangement reaction can be completed rapidly at very low temperature (- 78 ° C, 5 min) under the action of "tension acceleration effect", and the nucleophilic reagent α - stannonitrile has certain compatibility with electrophilic functional groups In addition, cyano group can be easily converted into other functional groups, which has important synthetic value Therefore, α - stannonitrile has become a nucleophilic reagent (nu1) for rearrangement in order to realize the idea of dearomatization of aryl high valent iodine After a simple exploration, they found that ET 3 SIH can capture the intermediate of dearomatization of aryl high valent iodine and give the product 3AA (Fig 1, EQ 3) Therefore, the research group realized the first case of dearomatization of aryl high valent iodine (angel Chem Int ed 2019, DOI: 10.1002/anie.201909019) Fig 2 the substrate range of aryl high valent iodine and α - tin nitrile (source: Angew Chem Int Ed, 2-bifunctional products; (2) in the case of different substituents in the ortho position of aryl high valent iodine, the reaction gives a specific regioselective product (excluding the ortho position containing methyl and ethyl aryl high valent iodine), which indicates that both the first nucleophile and the second nucleophile give a specific regioselectivity in the corresponding reaction steps; (3 ）The reaction has excellent functional group compatibility, such as benzyl chloride, α, β - unsaturated ester and other functional groups with high electrophilicity, and even olefins and heteroaromatics which are easily oxidized by high valent iodine can be compatible Therefore, the reaction has a wide range of substrate applications Fig 3 The scope of application of the second nucleophile (source: angel Chem Int ed.) is even more exciting In addition to the above reductant (ET 3 SIH), other nucleophiles, including electron rich aromatic hydrocarbons, olefins, allylsilicon, tmscn, enol silicone ether and heteroatom nucleophiles, are suitable for this reaction (Fig 3) Therefore, this reaction can be used to directly construct a variety of polysubstituted aliphatic carbon ring compounds from simple aryl high valent iodine Next, the research group also tried to explore the structure and properties of the de aromatization intermediates with the help of low-temperature NMR (Fig 4, EQ 4) Unexpectedly, the expected intermediate II was not found in the low-temperature NMR experiment, but the substitution of im with univalent iodine by tmsoac was observed The intermediate can be reduced by et 3sih or released by TBAF to give 4L of OAC substituted product The stability test of the intermediate im showed that when Im was placed at - 40 or - 20 ° C for 1 hour, it would decompose in varying degrees, resulting in a significant decrease in the yield of the products This indicates that the intermediate is not stable and needs to be converted at a very low temperature Fig 4 Observation of IM and stability test of im (source: angelw Chem Int ed.) this study realized the first dearylation of aryl high valent iodine by means of high-speed rearrangement reaction, established a new model of bifunctional dearylation reaction, and provided a new development idea for the transformation of aryl high valent iodine The results were published in angew Chem Int ed (DOI: 10.1002 / anie 201909019) Mr Zhao Weizhao and Mr Huang Xin, master's degree students of Zhejiang Normal University, work together for this paper The research work was supported by the youth fund of NSFC (21502171) Previous reports: Professor Peng Bo's research group of Zhejiang Normal University: Based on the high selective [5,5] - σ rearrangement reaction of "assembly / deproton" strategy, people and scientific research are getting more and more attention in economic life Today, 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 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.