Palladium-Catalyzed Chelation-Assisted Regioselective Oxidative Dehydrogenative Homocoupling/Ortho-Hydroxylation in N-Phenylpyrazoles
摘要:
A palladium-catalyzed pyrazole-directed regioselective oxidative C(sp2)-H functionalization of the N-phenyl ring in N-phenylpyrazoles to afford either a biaryl bis-pyrazole (via dehydrogenative homocoupling) or N-(o-hydroxyphenyl)pyrazole (via C-H oxygenation) or their mixture is described. The substitutions on the N-phenyl ring and the pyrazole ring and the dilution of the reaction medium with respect to the TFA/TFAA mixture (substrate concentration) have a remarkable influence on the outcome of the reaction. It was discovered that if the reactions were performed under highly dilute conditions (ca. 10 times) then N-(o-hydroxyphenyl)pyrazoles were the major or the sole products.
Ruthenium-Catalyzed <i>ortho</i>- and <i>meta</i>-H/D Exchange of Arenes
作者:Liang-Liang Zhao、Wei Liu、Zengyu Zhang、Hongyan Zhao、Qi Wang、Xiaoyu Yan
DOI:10.1021/acs.orglett.9b03955
日期:2019.12.20
Ruthenium-catalyzed aromatic H/D exchange in [D4]acetic acid has been developed. By using N-heteroarenes as directing groups, both ortho and meta positions are selectively deuterated with high levels of D incorporation. Moreover, this strategy provides an alternative way to achieve meta-C-H activation.
Site-selective arene C-H amination via photoredox catalysis
作者:Nathan A. Romero、Kaila A. Margrey、Nicholas E. Tay、David A. Nicewicz
DOI:10.1126/science.aac9895
日期:2015.9.18
cross-coupling chemistry has developed into one of the most reliable approaches to assemble complex aromatic compounds from preoxidized starting materials. More recently, transitionmetal–catalyzed carbon-hydrogen activation has circumvented the need for preoxidized starting materials, but this approach is limited by a lack of practical aminationprotocols. Here, we present a blueprint for aromatic carbon-hydrogen
为芳基 CN 键合开辟道路 药物化学家喜欢将 N 键添加到芳环的 C 原子上以制造生物活性化合物。通过利用可见光中的能量,Romero 等人。建立这些联系并将 CH 转化为 CN 键。他们使用一种吸收蓝色的吖啶离子来激活一个环 C 以供传入的 N 伙伴使用。然后,硝酰基自由基助催化剂 (TEMPO) 对 H 原子向 O 的转移进行了编排。该反应适用于广泛的底物,包括作为 N 源的铵。科学,这个问题 p。1326 两种催化剂利用可见光和氧气形成药物研究中感兴趣的碳氮键基序。在过去的几十年里,有机金属交叉偶联化学已发展成为从预氧化起始材料组装复杂芳香族化合物的最可靠方法之一。最近,过渡金属催化的碳氢活化避免了对预氧化起始材料的需求,但这种方法因缺乏实用的胺化方案而受到限制。在这里,我们提出了通过光氧化还原催化进行芳香碳氢功能化的蓝图,并描述了该策略在芳烃胺化中的应用。一种基于有机光氧化还原的催
Electrophotocatalysis with a Trisaminocyclopropenium Radical Dication
作者:He Huang、Zack M. Strater、Michael Rauch、James Shee、Thomas J. Sisto、Colin Nuckolls、Tristan H. Lambert
DOI:10.1002/anie.201906381
日期:2019.9.16
electrophotocatalytic oxidation platform. This chemistry employs a trisaminocyclopropenium (TAC) ion catalyst, which is electrochemically oxidized to form a cyclopropenium radical dication intermediate. The radical dication undergoes photoexcitation with visible light to produce an excited-state species with oxidizing power (3.33 V vs. SCE) sufficient to oxidize benzene and halogenated benzenes via single-electron
可见光光催化和电催化是促进化学反应的两种强大策略。在这里,这两种模式结合在电光催化氧化平台中。该化学过程采用三氨基环丙烯 (TAC) 离子催化剂,通过电化学氧化形成环丙烯自由基阳离子中间体。自由基阳离子在可见光下进行光激发,产生具有氧化能力(3.33 V vs. SCE)的激发态物质,足以通过单电子转移(SET)氧化苯和卤代苯,从而导致 CH/NH 与唑类偶联。提供了光激发物质的强氧化行为的基本原理,同时通过顺式2,6-二甲基哌啶部分的特定构象合理化了催化剂的稳定性。
Rhodium(I)-Catalyzed Direct Carboxylation of Arenes with CO<sub>2</sub> via Chelation-Assisted C−H Bond Activation
作者:Hajime Mizuno、Jun Takaya、Nobuharu Iwasawa
DOI:10.1021/ja109097z
日期:2011.2.9
products in good yields. The catalysis is proposed to consist of methylrhodium(I) species as the key intermediate, which undergoes C-Hactivation to afford rhodium(III), followed by reductive elimination of methane to give nucleophilic arylrhodium(I). This approach demonstrates promising application of C-Hbondactivation strategy in the field of carbon dioxide fixation.
[EN] OREXIN RECEPTOR ANTAGONISTS WHICH ARE [ORTHO BI (HETERO )ARYL]-[2-(META BI (HETERO )ARYL)-PYRROLIDIN-1-YL]-METHANONE DERIVATIVES<br/>[FR] ANTAGONISTES DES RÉCEPTEURS DE L'OREXINE, QUI SONT DES DÉRIVÉS [ORTHO BI (HETERO )ARYL]-[2-(META BI (HETERO )ARYL)-PYRROLIDIN-1-YL]-METHANONE
申请人:ACTELION PHARMACEUTICALS LTD
公开号:WO2014057435A1
公开(公告)日:2014-04-17
The present invention relates to [ortho bi-(hetero-)aryl]-[2-(meta bi-(hetero-)aryl)-pyrrolidin-1-yl]- methanone derivatives of formula (I) wherein R, and the rings A1 A2 and A3 are as described in the description, to pharmaceutically acceptable salts thereof, to their preparation, to pharmaceutical compositions containing one or more compounds of formula (I), and to their use as pharmaceuticals, especially to their use as orexin receptor antagonists.