Efficient Synthesis of Aryl Boronates via Zinc-Catalyzed Cross-Coupling of Alkoxy Diboron Reagents with Aryl Halides at Room Temperature
作者:Shubhankar Kumar Bose、Todd B. Marder
DOI:10.1021/ol502120q
日期:2014.9.5
A zinc(II)/NHC system catalyzes the borylation of aryl halides with diboron (4) reagents in the presence of KOMe at rt. This transformation can be applied to a broad range of substrates with high functional group compatibility. Radical scavenger experiments do not support a radical-mediated process.
Visible Light-Induced Borylation of C–O, C–N, and C–X Bonds
作者:Shengfei Jin、Hang. T. Dang、Graham C. Haug、Ru He、Viet D. Nguyen、Vu T. Nguyen、Hadi D. Arman、Kirk S. Schanze、Oleg V. Larionov
DOI:10.1021/jacs.9b12519
日期:2020.1.22
photocatalytic borylation method that can effect borylation of a wide range of substrates, including strong C‒O bonds, remains elusive. Herein, we report a general, metal-free visible light-induced photocatalytic borylation platform that enables borylation of electron rich derivatives of phenols and anilines, chloroarenes, as well as other haloarenes. The reac-tion exhibits excellent functional group
硼酸是中心重要的功能基序和合成前体。可见光诱导的硼酸化可以提供结构多样化的硼酸盐,但一种广泛有效的光催化硼酸化方法可以影响包括强 C-O 键在内的多种底物的硼化,仍然难以实现。在此,我们报告了一种通用的、无金属的可见光诱导光催化硼化平台,该平台能够对苯酚和苯胺、氯芳烃以及其他卤代芳烃的富电子衍生物进行硼化。该反应表现出优异的官能团耐受性,正如一系列结构复杂底物的硼化反应所证明的那样。值得注意的是,该反应是由吩噻嗪催化的,这是一种简单的有机光催化剂,MW< 200通过质子耦合电子转移机制介导了以前无法实现的可见光诱导的苯酚衍生物单电子还原,还原电位为~-3 V vs SCE。机理研究指出了光催化剂-碱相互作用的关键作用。
Metal‐Free Radical Borylation of Alkyl and Aryl Iodides
A metal‐free radical borylation of alkyl and aryl iodides with bis(catecholato)diboron (B2cat2) as the boron source under mild conditions is introduced. The borylation reaction is operationally easy to conduct and shows high functional group tolerance and broad substrate scope. Radical clock experiments and density functional theory calculations provide insights into the mechanism and rate constants
介绍了在温和条件下以双(儿茶酚)二硼(B 2 cat 2 )作为硼源对烷基碘化物和芳基碘化物进行金属自由基硼化反应。硼化反应操作简便,具有较高的官能团耐受性和广泛的底物范围。自由基时钟实验和密度泛函理论计算提供了对 B 2 cat 2的 C 自由基硼化的机制和速率常数的见解。
Anomalous Reactivity of Silylborane: Transition-Metal-Free Boryl Substitution of Aryl, Alkenyl, and Alkyl Halides with Silylborane/Alkoxy Base Systems
作者:Eiji Yamamoto、Kiyotaka Izumi、Yuko Horita、Hajime Ito
DOI:10.1021/ja309578k
日期:2012.12.12
An unexpected borylation of organic halides with a silyborane in the presence of an alkoxy base has been observed. This formal nucleophilic boryl substitution can be applied to a broad range of substrates with high functional group compatibility. Even stericallyhindered aryl bromides afforded the corresponding boryl compounds in high yields. Preliminary mechanistic studies indicated that this boryl
Zinc‐Catalyzed Dual C–X and C–H Borylation of Aryl Halides
作者:Shubhankar Kumar Bose、Andrea Deißenberger、Antonius Eichhorn、Patrick G. Steel、Zhenyang Lin、Todd B. Marder
DOI:10.1002/anie.201505603
日期:2015.9.28
A zinc‐catalyzed combined CX and CH borylation of arylhalides using B2pin2 (pin=OCMe2CMe2O) to produce the corresponding 1,2‐diborylarenes under mild conditions was developed. Catalytic CH bond activation occurs ortho to the halide groups if such a site is available or meta to the halide if the ortho position is already substituted. This method thus represents a novel use of a group XII catalyst