α-Halo carbonyls enable meta selective primary, secondary and tertiary C–H alkylations by ruthenium catalysis
作者:Andrew J. Paterson、Callum J. Heron、Claire L. McMullin、Mary F. Mahon、Neil J. Press、Christopher G. Frost
DOI:10.1039/c7ob01192j
日期:——
selective C–H alkylation of arenes is described using a wide range of α-halo carbonyls as coupling partners. Previously unreported primary alkylations with high meta selectivity have been enabled by this methodology whereas using straight chain alkyl halides affords ortho substituted products. Mechanistic analysis reveals an activation pathway whereby cyclometalation with a ruthenium(II) complex activates
para-Selective hydroxylation of alkylarylethers is established, which proceeds with a ruthenium(II) catalyst, hypervalent iodine(III) and trifluoroacetic anhydride via a radical mechanism. This protocol tolerates a wide scope of substrates and provides a facile and efficient method for preparing clinical drugs monobenzone and pramocaine on a gram scale.
<i>N</i>-Acyl Amino Acid Ligands for Ruthenium(II)-Catalyzed <i>meta</i>-C–H <i>tert</i>-Alkylation with Removable Auxiliaries
作者:Jie Li、Svenja Warratz、Daniel Zell、Suman De Sarkar、Eloisa Eriko Ishikawa、Lutz Ackermann
DOI:10.1021/jacs.5b08435
日期:2015.11.4
Acylated amino acid ligands enabled ruthenium(II)-catalyzed C-H functionalizations with excellent levels of meta-selectivity. The outstanding catalytic activity of the ruthenium(II) complexes derived from monoprotected amino acids (MPAA) set the stage for the first ruthenium-catalyzed meta-functionalizations with removable directing groups. Thereby, meta-alkylated anilines could be accessed, which
酰化氨基酸配体使钌 (II) 催化的 CH 官能化具有出色的元选择性。源自单保护氨基酸 (MPAA) 的钌 (II) 配合物的出色催化活性为第一个具有可移除导向基团的钌催化元功能化奠定了基础。因此,可以使用间烷基化苯胺,这是很难通过其他直接苯胺官能化方法制备的。多功能钌 (II)-MPAA 的稳健性通过在苯胺衍生物以及吡啶基、嘧啶基和吡唑基取代的芳烃上用叔烷基卤化物进行远程 CH 转化具有挑战性来体现。详细的机理研究为最初的可逆 CH 钌化提供了强有力的支持,然后通过均裂键裂解激活 SET 型 C-Hal。动力学分析通过反应速率对钌催化剂浓度的不寻常的二阶依赖性证实了这一假设。总体而言,该报告强调了源自酰化氨基酸的钌配合物的卓越催化活性,这应该证明有助于超越远程功能化的 CH 活化化学。
Solvent-Free Ruthenium(II)-Catalyzed C-H Activation: Synthesis of Alkenylarylpyrazole Derivatives
作者:Sanchari Shome、Surya Prakash Singh
DOI:10.1002/ejoc.201500634
日期:2015.9
N-arylpyrazoles by using styrenes and acrylates in the presence of Cu(OAc)2·H2O in open air. The highly step-economical C–H bond functionalization process is characterized by a wide substrate scope and significant chemoselectivity, which allowed direct alkenylation to be performed either under solvent-free reaction conditions or by using a user-friendly solvent system in which water was present as the major component