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。
Synthesis of Arylstannanes from Arylamines
作者:Alicia B. Chopa、María T. Lockhart、Gustavo Silbestri
DOI:10.1021/om000859p
日期:2001.7.1
Arylamines have been converted into aryltrimethylammonium salts, which on reaction with sodium trimethylstannide (1) in liquid ammonia afford aryltrimethylstannanes by the SRN1 mechanism. With (4-methoxyphenyl)- (2), (1-naphthyl)- (4), phenyl- (6), (4-acetylphenyl)- (8), and (4-cyanophenyl)trimethylammonium salts (10) the substitution products are obtained in good to excellent yields (45−100%). Also
Trialkylammonium salt degradation: implications for methylation and cross-coupling
作者:Jack B. Washington、Michele Assante、Chunhui Yan、David McKinney、Vanessa Juba、Andrew G. Leach、Sharon E. Baillie、Marc Reid
DOI:10.1039/d1sc00757b
日期:——
being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational
已知三烷基铵(最显着的是N,N,N-三甲基苯铵)盐通过芳基和N-甲基均显示出双重反应性。因此,这些盐已广泛应用于交叉偶联,芳基醚化,氟放射性标记,相转移催化,超分子识别,聚合物设计和(最近)甲基化。然而,它们作为亲电甲基化试剂的应用仍未得到充分开发,并且缺乏对它们的芳基化与甲基化反应性的了解。本研究提出了N,N,N的机械降解分析。-三甲基苯胺盐,并突出了这一重要类别盐对合成应用的意义。在固相和固溶阶段的动力学降解研究已经深入了解了影响苯胺盐稳定性的物理和化学参数。盐降解的1 H NMR动力学分析表明,热降解为甲基碘和母体苯胺,与闭壳S N一致2位降解途径,而甲基碘是应用甲基化程序中的关键反应物种。此外,还研究了卤化物和非亲核抗衡离子对盐降解的影响,以及氘同位素和溶剂的影响。新的力学见解使人们能够研究三甲基苯胺盐在O-甲基化中的应用以及在改进的交叉偶联策略中的应用。最后,详细的计算研究有助于
Synergic Interplay Between Halogen Bonding and Hydrogen Bonding in the Activation of a Neutral Substrate in a Nanoconfined Space
作者:Pellegrino La Manna、Margherita De Rosa、Carmen Talotta、Antonio Rescifina、Giuseppe Floresta、Annunziata Soriente、Carmine Gaeta、Placido Neri
DOI:10.1002/anie.201909865
日期:2020.1.7
The principle of amplified halogenbonding (XB) in a small space is exploited as a catalytic tool for the activation of an XB acceptor substrate in a nanoconfined environment. The inner cavity of the resorcinarene capsule has been equipped with an XB catalyst bearing an ammonium unit acting as a Trojan horse to drive the catalyst inside the capsule. In the presence of a specific XB catalyst, the capsule