One-pot Suzuki coupling of aromatic amines via visible light photocatalyzed metal free borylation using t-BuONO at room temperature
摘要:
A convenient and efficient metal free borylation of aromatic amines has been achieved using tertiary butyl nitrite and B(2)Pin(2) (bis(pinacolato)diborane) under irradiation with blue LED light at room temperature. This protocol has been successfully extended to subsequent Suzuki coupling in the same pot. Thus a series of functionalized aryl boronates and biaryls are obtained in high yields in a shorter reaction period starting from relatively cheap aryl amines in one-pot avoiding isolation of potentially unstable and hazardous intermediates. (C) 2016 Elsevier Ltd. All rights reserved.
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。
Nickel-catalyzed borylation of arenes and indoles via C–H bond cleavage
作者:Takayuki Furukawa、Mamoru Tobisu、Naoto Chatani
DOI:10.1039/c5cc01378j
日期:——
The first nickel-catalyzed method for the borylation of carbon–hydrogen bonds in arenes and indoles is described. The use of an N-heterocyclic carbene ligand is essential for an efficient reaction, with an N-cyclohexyl-substituted derivative being optimal. This method is readily applied to the gram scale synthesis of 2-borylindole.
this reaction amenable for industry. A plethora of synthetically very useful halogenated anilines, which often cannot be prepared via other transition-metal-catalyzed aminations, are readily produced using this method. Particularly, the orthogonal reactivity between pinacol arylborates and aryl iodides is demonstrated. Preliminary deuterium-labeling studies reveal a redox-neutral ipso-protonation mechanism
据报道,钯( II )/降冰片烯协同催化可实现频哪醇芳基硼酸盐或杂芳基硼酸盐的氧化还原中性邻位-C -H胺化,用于合成结构多样的苯胺。该方法具有可扩展性、稳健性(耐空气和湿气)、不含膦配体,并且与多种功能兼容。这些实用的特征使得该反应适合工业界。使用这种方法可以很容易地生产大量合成上非常有用的卤代苯胺,这些卤代苯胺通常无法通过其他过渡金属催化的胺化来制备。特别是,证明了频哪醇芳基硼酸盐和芳基碘化物之间的正交反应性。初步的氘标记研究揭示了该过程的氧化还原中性原质子化机制,这必将为该领域的未来发展带来启发。总体而言,该方法的范围极其广泛(47 个示例)和可靠性,加上频哪醇芳基硼酸酯的广泛可用性,使该化学成为现有苯胺合成方法的宝贵补充。
Nickel-Catalyzed Ipso-Borylation of Silyloxyarenes via C–O Bond Activation
作者:Wesley L. Pein、Eric M. Wiensch、John Montgomery
DOI:10.1021/acs.orglett.1c01280
日期:2021.6.18
The conversion of silyloxyarenes to boronic acid pinacol esters via nickel catalysis is described. In contrast to other borylation protocols of inert C–O bonds, the method is competent in activating the carbon–oxygen bond of silyloxyarenes in isolated aromatic systems lacking a directing group. The catalytic functionalization of benzyl silyl ethers was also achieved under these conditions. Sequential