羟基化(杂)芳烃在许多行业中都受到重视,既是最终产品的关键成分,又是可多样化的合成结构单元。因此,开发补充和解决引入芳香族羟基的现有方法的局限性的反应是一个重要的目标。为此,我们应用碱催化的卤素转移(X-转移)来实现弱酸性N-杂芳烃和苯的直接C-H羟基化。该方案采用醇盐碱催化从牺牲的 2-卤代噻吩氧化剂到芳基底物的 X 转移,形成发生亲核羟基化的 S N Ar 活性中间体。该过程的关键是使用 2-苯基乙醇作为廉价的氢氧化物替代物,在芳族取代和快速消除后,提供羟基化芳烃和苯乙烯副产物。使用简单的2-卤代噻吩可以实现6元N-杂芳烃和1,3-唑衍生物的C-H羟基化,而合理设计的2-卤代苯并噻吩氧化剂则将范围扩展到缺电子苯底物。机理研究表明芳香族 X 转移是可逆的,这表明去质子化、卤化和取代步骤协同作用,表现出独特的选择性趋势,不一定依赖于酸性最强的芳基位置。通过简化的目标分子合成、与替代 C-H
羟基化(杂)芳烃在许多行业中都受到重视,既是最终产品的关键成分,又是可多样化的合成结构单元。因此,开发补充和解决引入芳香族羟基的现有方法的局限性的反应是一个重要的目标。为此,我们应用碱催化的卤素转移(X-转移)来实现弱酸性N-杂芳烃和苯的直接C-H羟基化。该方案采用醇盐碱催化从牺牲的 2-卤代噻吩氧化剂到芳基底物的 X 转移,形成发生亲核羟基化的 S N Ar 活性中间体。该过程的关键是使用 2-苯基乙醇作为廉价的氢氧化物替代物,在芳族取代和快速消除后,提供羟基化芳烃和苯乙烯副产物。使用简单的2-卤代噻吩可以实现6元N-杂芳烃和1,3-唑衍生物的C-H羟基化,而合理设计的2-卤代苯并噻吩氧化剂则将范围扩展到缺电子苯底物。机理研究表明芳香族 X 转移是可逆的,这表明去质子化、卤化和取代步骤协同作用,表现出独特的选择性趋势,不一定依赖于酸性最强的芳基位置。通过简化的目标分子合成、与替代 C-H
Metal-Free, Oxidant-Free, and Controllable Graphene Oxide Catalyzed Direct Iodination of Arenes and Ketones
作者:Jingyu Zhang、Shiguang Li、Guo-Jun Deng、Hang Gong
DOI:10.1002/cctc.201701182
日期:2018.1.23
oxide (GO)‐catalyzed iodination of arenes and ketones with iodine in a neutralmedium was explored. This iodination protocol was performed by using a simple technique to avoid the use of external metal catalysts and oxidants and harsh acidic/basic reaction conditions. In addition, by this method the degree of iodination could be controlled, and the reaction was scalable and compatible with air. This strategy
Synthesis of Dibenzothiophenes and Related Classes of Heterocycles by Using Functionalized Dithiocarbamates
作者:Marcel Kienle、Andreas Unsinn、Paul Knochel
DOI:10.1002/anie.201001025
日期:2010.6.28
A round trip: Readily available dithiocarbamates can undergo ringclosure to give functionalized sulfurheterocycles (see scheme). These heteroaromatic compounds can be further functionalized by directed alumination and subsequently trapped with various electrophiles.
through the distorted bibenzothiophene because of the nido-decaborane unit. Moreover, the intramolecular chargetransferstate should be realized because of electronic interactioninvolving the nido-decaborane unit in the excited state. Furthermore, it was demonstrated that the nido-decaborane-fused compound possessed solid-state emission and mechanochromic luminescent properties. The π-conjugation on the
Benzo[<i>b</i>]thiophene Fusion Enhances Local Borepin Aromaticity in Polycyclic Heteroaromatic Compounds
作者:Reid E. Messersmith、Sangeeta Yadav、Maxime A. Siegler、Henrik Ottosson、John D. Tovar
DOI:10.1021/acs.joc.7b02512
日期:2017.12.15
crystallographic, and computational characterization to literature compounds gave valuable insights about the aromaticity of these symmetrically fused [b,f]borepins. The fusion of benzo[b]thiophene units to the central borepin cores forced a high degree of local aromaticity within the borepin moieties relative to other known borepin-based polycyclic aromatics. Each isomer had unique electronic responses