The practical utility of decarboxylative transformations in organic synthesis is discussed, and the decarboxylative deuteration of (hetero)aromatic carboxylic acids is disclosed as a further example. Various monodeuterated arenes were synthesized under mild conditions, in a single step from easily accessible aromatic carboxylic acids and deuterium oxide. Copper catalysts were found to have the widest scope, but silver catalysts are superior for some ortho-substituted benzoates. A few substrates, e.g. quinoline-2-carboxylic acid, decarboxylate even in the absence of a metal catalyst.
work reports a metal-free method for deuteriumlabeling covering a broad range of substrate including phenolic compounds (i.e. flavonoids and stilbenes), indoles, pyrroles, carbonyl compounds, and steroids. This method was also applied for commonly used drugs such as loxoprofen, haloperidol, stanolone, progesterone, androstenedione, donepezil, ketorolac, adrenosterone, cortisone, pregnenolone, and dexamethasone
在这里,我们揭示了一种简单的卤化氘 (DX) 生成方法,该方法由合成化学实验室中现成的普通且廉价的试剂制成,i . e . 在温和条件下,异戊二烯基、烯丙基和炔丙基卤化物。我们设想,原位生成酸卤化氘可用于酸催化反应,并可用于有机催化氘化。本工作报告了一种无金属氘标记方法,覆盖范围广泛的底物,包括酚类化合物(即. 类黄酮和芪)、吲哚、吡咯、羰基化合物和类固醇。该方法也适用于常用药物,如洛索洛芬、氟哌啶醇、甾烷酮、黄体酮、雄烯二酮、多奈哌齐、酮咯酸、肾上腺素、可的松、孕烯醇酮和地塞米松。这项工作证明了一些氘代化合物的克级无色谱合成。这项工作提供了一种简单、清洁且无副产物的位点选择性氘代,并且氘代产物无需色谱分离即可获得。当将这些引发剂用于其他酸催化反应时,DX 的氘同位素效应可能会提供不同于使用普通酸的反应所获得的产物。虽然异戊二烯卤化物自发转化为酸的机制尚不清楚,
Silver-catalyzed regioselective deuteration of (hetero)arenes and α-deuteration of 2-alkyl azaarenes
作者:Baobiao Dong、Xuefeng Cong、Na Hao
DOI:10.1039/d0ra02358b
日期:——
A simple silver-catalyzed regioselective deuteration of (hetero)arenes and α-deuteration of 2-alkyl azaarenes has been described. This strategy provides an efficient and practical avenue to access various deuterated electron-rich arenes, azaarenes and α-deuterated 2-alkyl azaarenes with good to excellent deuterium incorporation utilizing D2O as the source of deuterium atoms.
已经描述了(杂)芳烃的简单银催化区域选择性氘化和 2-烷基氮杂芳烃的 α-氘化。该策略为利用 D 2 O 作为氘原子源获得各种氘代富电子芳烃、氮杂芳烃和 α-氘代 2-烷基氮杂芳烃提供了一种有效且实用的途径,这些氘代具有良好的氘掺入能力。
Ethynyl Benziodoxolones for the Direct Alkynylation of Heterocycles: Structural Requirement, Improved Procedure for Pyrroles, and Insights into the Mechanism
作者:Jonathan P. Brand、Clara Chevalley、Rosario Scopelliti、Jérôme Waser
DOI:10.1002/chem.201200200
日期:2012.4.27
accelerating effect of a methyl substituent in both the 3‐ and 6‐position of triisopropylsilylethynyl‐1,2‐benziodoxol‐3(1H)‐one (TIPS‐EBX) on the reaction rate was observed. Competitive experiments between substrates of different nucleophilicity, deuterium labeling experiments, as well as the regioselectivity observed are all in agreement with electrophilic aromatic substitution. Gold(III) 2‐pyridinecarboxylate
作者:Sami Lakhdar、Martin Westermaier、François Terrier、Régis Goumont、Taoufik Boubaker、Armin R. Ofial、Herbert Mayr
DOI:10.1021/jo0614339
日期:2006.11.1
and parallel correlations are obtained on plotting the measured N values versus the pKa(H2O) values for protonation at C-3 of 5-X-substituted indoles and 5-X-substituted 2-methylindoles, respectively. This splitting reveals that the presence of the 2-methyl group causes steric hindrance to the approach of 2 from the adjacent C-3 position of an indole structure. The N vs pKa(H2O) correlation for 5-X-substituted
在乙腈和/或二氯甲烷中,已研究了吲哚(1a),N-甲基吲哚(1b),5-甲氧基吲哚(1c)和5-氰基吲哚(1d)与一组参考苯甲酰基阳离子偶联的动力学。反应的二级速率常数与二苯甲基阳离子的亲电参数E线性相关。这样就可以确定反应性参数N和s,根据线性自由焓关系log k(20°C)= s(1 a - d)来表征1a - d的亲核性。Ñ + ë)(度Acc。化学式RES。2003,36,66)。如此定义的亲核性参数很好地描述了1a - d与4,6-二硝基苯并呋喃(2)的反应,4,6-二硝基苯并呋喃(2)是一种中性超亲电杂芳族化合物,其亲电性(E)最近已确定。在此基础上,已在乙腈中研究了2与多种吲哚结构偶联的动力学,从而导致该家族的π过量碳亲核试剂在亲核标度N的大范围内排名。重要的是,分别绘制5-X取代的吲哚和5-X取代的吲哚的C-3的质子化的N值与p K a(H 2 O)值的关系图时,得到了两个