Rh(I)–Bisphosphine-Catalyzed Asymmetric, Intermolecular Hydroheteroarylation of α-Substituted Acrylate Derivatives
作者:Claire M. Filloux、Tomislav Rovis
DOI:10.1021/ja511445x
日期:2015.1.14
Asymmetric hydroheteroarylation of alkenes represents a convenient entry to elaborated heterocyclic motifs. While chiral acids are known to mediate asymmetric addition of electron-rich heteroarenes to Michael acceptors, very few methods exploit transitionmetals to catalyzealkylation of heterocycles with olefins via a C–H activation, migratory insertion sequence. Herein, we describe the development
烯烃的不对称氢杂芳基化代表了复杂杂环基序的便捷进入。虽然已知手性酸可以介导富电子杂芳烃向 Michael 受体的不对称加成,但很少有方法利用过渡金属通过 C-H 活化、迁移插入序列催化杂环与烯烃的烷基化。在此,我们描述了α-取代丙烯酸酯与苯并恶唑的不对称分子间氢杂芳基化反应的发展。该反应以中等至优异的产率和良好至优异的对映选择性提供2-取代的苯并恶唑。值得注意的是,一系列机制研究似乎与涉及 Rh(I)-烯醇化物对映选择性质子化的途径相矛盾,尽管事实上在芳基硼酸与甲基丙烯酸酯衍生物的相关加成中几乎一致地调用了这种机制。相反,有证据表明,迁移插入或β-氢化物消除具有对映决定性,Rh(I)-烯醇化物异构化为Rh(I)-杂苄基物质可将所得的α-立构中心与差向异构化隔离开来。庞大的配体 CTH-(R)-Xylyl-P-Phos 对于反应性和对映选择性至关重要,因为它可能会阻止苯并恶唑底物或中间体与循
A Versatile Rhodium(I) Catalyst System for the Addition of Heteroarenes to both Alkenes and Alkynes by a CH Bond Activation
作者:Jaeyune Ryu、Seung Hwan Cho、Sukbok Chang
DOI:10.1002/anie.201200120
日期:2012.4.10
efficient and convenient rhodium catalyst system was developed for the title transformation. A base co‐catalyst was found to facilitate the key arene CH bond‐activation step and substrate scope was very broad, including both electron‐deficient pyridine N‐oxides, and electron‐rich azoles. The catalytic system was effective for the hydroheteroarylation of both alkenes and alkynes and gave excellent regio‐
Selective Construction of C−C and C=C Bonds by Manganese Catalyzed Coupling of Alcohols with Phosphorus Ylides
作者:Xin Liu、Thomas Werner
DOI:10.1002/adsc.202001209
日期:2021.2.16
manganese catalyzed coupling of alcohols with phosphorus ylides. The selectivity in the coupling of primary alcohols with phosphorus ylides to form carbon‐carbon single (C−C) and carbon‐carbon double (C=C) bonds can be controlled by the ligands. In the conversion of more challenging secondary alcohols with phosphorus ylides the selectivity towards the formation of C−C vs. C=C bonds can be controlled by the