Hydrazone as the Directing Group for Ir-Catalyzed Arene Diborylations and Sequential Functionalizations
作者:Abel Ros、Rocío López-Rodríguez、Beatriz Estepa、Eleuterio Álvarez、Rosario Fernández、José M. Lassaletta
DOI:10.1021/ja300308c
日期:2012.3.14
The use of hemilabile pyridine-hydrazone N,N-ligands allows the highlyselective Ir-catalyzed ortho,ortho'-directed diborylation of aromatic N,N-dimethylhydrazones in near-quantitative yields. One-pot sequential Suzuki-Miyaura cross-coupling with different arylbromides provides a short entry to unsymmetrically substituted 2,6-diarylbenzaldehyde derivatives.
使用 hemilabile 吡啶-腙 N,N-配体允许以接近定量的产率对芳香族 N,N-二甲基腙进行高度选择性的 Ir 催化的邻、邻'-定向二硼化。与不同芳基溴化物的一锅顺序 Suzuki-Miyaura 交叉偶联为不对称取代的 2,6-二芳基苯甲醛衍生物提供了一个捷径。
Use of Hemilabile N,N Ligands in Nitrogen-Directed Iridium-Catalyzed Borylations of Arenes
作者:Abel Ros、Beatriz Estepa、Rocío López-Rodríguez、Eleuterio Álvarez、Rosario Fernández、José M. Lassaletta
DOI:10.1002/anie.201104544
日期:2011.12.2
The hemilabile character of 2‐pyridyl carbaldehyde hydrazones as N,N bidentate ligands is key to performing regioselective IrIII‐catalyzed ortho borylations of 2‐aryl pyridines(isoquinolines) and aromatic N,N‐dimethylhydrazones (see scheme; pin=pinacol, Bn=benzyl). Internal “ate” complexes or products free from NB interactions are formed depending on the steric properties of the substrates.
Gold-Catalyzed Highly Selective Photoredox C(sp<sup>2</sup>
)−H Difluoroalkylation and Perfluoroalkylation of Hydrazones
作者:Jin Xie、Tuo Zhang、Fei Chen、Nina Mehrkens、Frank Rominger、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/anie.201508622
日期:2016.2.18
hydrazones are highly functionalized, versatile molecules. A mild reduction of the coupling products can efficiently produce gem‐difluoromethylated β‐amino phosphonic acids and β‐amino acid derivatives. In mechanistic studies, a difluoroalkyl radical intermediate was detected by an EPR spin‐trappingexperiment, indicating that a gold‐catalyzed radical pathway is operating.
据报道,使用容易获得的R F -Br试剂,gold的金催化光氧化还原C(sp 2)-H二氟烷基化和hydr的全氟烷基化。所得的宝石二氟甲基化和全氟烷基化的azo是高度官能化的多用途分子。偶合产物的轻度减少可以有效地生产出宝石-二氟甲基化的β-氨基膦酸和β-氨基酸衍生物。在机理研究中,通过EPR自旋捕获实验检测到二氟烷基自由基中间体,表明金催化的自由基途径正在起作用。
C–H Difluoroalkylation of Aldehyde Hydrazones with Functionalized Difluoromethyl Bromides under Copper Catalysis
The Cu-catalyzed direct difluoroalkylation of aldehyde hydrazones with functionalized difluoromethyl bromides is described. The reaction yields stereodefined α,α–difluoro-β-keto hydrazones under mild conditions and can be carried out at a scale that opens up the possibility of practical applications.
Copper-Catalyzed Double C–H Alkylation of Aldehyde-Derived <i>N</i>,<i>N</i>-Dialkylhydrazones with Polyhalomethanes: Flexible Access to 4-Functionalized Pyrazoles
作者:Alexis Prieto、Didier Bouyssi、Nuno Monteiro
DOI:10.1021/acscatal.6b02439
日期:2016.10.7
have been made accessible in a single step from readily available aldehyde-derived N,N-dialkyl hydrazones and functionalized polyhalomethane derivatives. The process is believed to follow copper-catalyzed cascade C(sp2)–H haloalkylation/C(sp3)–H cyclization/aromatization reaction sequences.