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基于自由基机理的有机硼酯化反应

刘谦益a, 张雷a, 莫凡洋a,b   

  1. a 北京大学 工学院能源与资源工程系 北京 100871;
    b 江苏省东海县硅产业科技创新中心 连云港 222300
  • 发布日期:2020-08-01
  • 通讯作者: 莫凡洋 E-mail:fmo@pku.edu.cn
  • 作者简介:刘谦益,北京大学工学院2017级博士生。本科毕业于北京大学工学院,博士阶段师从莫凡洋特聘研究员,主要从事有机自由基硼酯化和清洁高效有机合成方法学研究;张雷,北京大学工学院2016级博士生。2012-2016年于北京理工大学获得学士学位,2016年至今,在莫凡洋特聘研究员指导下攻读博士学位,主要从事有机电化学合成与过渡金属催化反应机理研究;莫凡洋,北京大学工学院特聘研究员、博士生导师。分别于2004年与2006年在北京理工大学获得学士与硕士学位(导师:周智明教授)。2006至2010年就读于北京大学化学与分子工程学院,获得有机化学博士学位(导师:王剑波教授)。2010至2012年在Scripps研究所从事博士后研究(导师:张庆海教授);2012至2015年在德克萨斯州大学奥斯汀分校从事博士后研究(导师:董广彬教授)。2015年起担任北京大学工学院特聘研究员,主要研究方向包括资源导向的有机合成方法学、半导体氧化物的改性以及分子电子学。
  • 基金资助:
    项目受国家自然科学基金(No.21772003,21933001)资助.

Organic Borylation Reactions via Radical Mechanism

Liu Qianyia, Zhang Leia, Mo Fanyanga,b   

  1. a College of Engineering, Peking University, Beijing, 100871;
    b Jiangsu Donghai Silicon Industry S&T Innovation Center, Lianyungang, 222300
  • Published:2020-08-01
  • Supported by:
    Project supported by the National Natural Science Foundation of China (No. 21772003 and 21933001).

有机硼酸和硼酸酯化合物是以Suzuki-Miyaura偶联为代表的众多种重要化学反应的底物。发展有机硼化合物的高效合成方法具有重要意义。近十年来,基于自由基机理的有机硼酯化反应得以发展,并迅速成为高效构建碳硼键的一类重要方法。自由基硼酯化反应的一般策略为,利用不同反应条件产生的碳自由基活泼中间体与联硼化合物反应,生成相应的有机硼酸或硼酸酯。本文根据反应产生的碳自由基种类的不同,将硼酯化反应分为基于芳基自由基和基于烷基自由基两大部分。各部分依据自由基前体种类的不同,又具体分为基于碳氮、碳氧、碳卤等化学键的硼酯化反应以及羧酸脱羧硼酯化反应。最后,我们进一步总结分析了未来自由基硼酯化反应的研究趋势。

关键词: 自由基化学, 硼酯化反应, 联硼化合物, 芳基自由基, 烷基自由基

Organoboronic acids and esters are highly valuable building blocks in cross-coupling reactions and practical intermediates of various functional group transformations. Additionally, organoboronic acids can be utilized directly as small molecule drugs. Therefore, development of efficient methods to synthesize organoboronic compounds is of significant importance. Traditional pathways to synthesize organoboronic compounds mainly rely on electrophilic borylation of organometallic reagent and transition-metal-catalyzed borylation. Radical intermediates have unique chemical property. It is quite different from the property of polar intermediates resulted from the heterolysis of chemical bonds, and also different from the property of the organometallic compounds during transition metal catalysis. As such, borylation based on radical mechanism can realize distinctive reaction process, substrate scope, reaction selectivity, etc., and have great potential in synthesis of organoboronic compounds. In 2010, the Wang's group first reported borylation via radical mechanism. This method realized an efficient direct conversion of anilines into aryl organoboronic esters. Inspired by this innovative work, more and more borylation methods via radical intermediates have been reported and developed as a new avenues for C-B bond formation in the past decade. A series of studies showed that organoboronic acids and esters could be efficiently constructed by the reaction of aryl/alkyl radicals with diboron compounds. In this paper, we summarized the recent development of borylation reactions via radical mechanism, including aryl and alkyl radical borylation. As for aryl radical borylation, activation of substrates containing C-N, C-O, C-S, C-X (X=halogen) bonds and carboxylic acids to C-B bond was summarized respectively. As for alkyl radical borylation, activation of substrates containing C-N, C-O, C-X (X=halogen), C-C bonds and carboxylic acids to C-B bond was summarized respectively. Finally, we made a perspective on the future development direction of this research area.

Key words: adical chemistry, borylation reaction, diboron compounds, aryl radical, alkyl radical