Investigations into Ruthenium Metathesis Catalysts with Six-Membered Chelating NHC Ligands: Relationship between Catalyst Structure and Stereoselectivity
作者:Koji Endo、Myles B. Herbert、Robert H. Grubbs
DOI:10.1021/om4006966
日期:2013.9.23
A series of rutheniumcatalysts bearing five-membered chelating NHC architectures that exhibit very high Z-selectivity in a variety of metathesis reactions have recently been reported. It was envisioned that catalysts possessing six-membered chelates could similarly exhibit high Z-selectivity and address limitations of this methodology. We thus prepared a number of new catalysts and systematically
最近报道了一系列带有五元螯合 NHC 结构的钌催化剂,这些结构在各种复分解反应中表现出非常高的Z选择性。设想具有六元螯合物的催化剂可以类似地表现出高Z选择性并解决该方法的局限性。因此,我们制备了许多新催化剂,并系统地研究了 NHC 和阴离子配体对其立体选择性的影响。在标准的易位分析中,只有含有六元螯合 NHC 结构和 η 2结合阴离子配体的催化剂有利于Z-烯烃产物。此外,用更大的N-芳基取代导致改善Z-选择性。本研究中发现的配体结构对立体选择性的影响将有助于未来设计高活性和Z选择性钌催化剂。
Pd(II)-Catalyzed Enantioselective C−H Olefination of Diphenylacetic Acids
作者:Bing-Feng Shi、Yang-Hui Zhang、Jonathan K. Lam、Dong-Hui Wang、Jin-Quan Yu
DOI:10.1021/ja909571z
日期:2010.1.20
Pd(II)-catalyzed enantioselective C-H olefination of diphenylaceticacid substrates has been achieved through the use of monoprotected chiral amino acid ligands. The absolute configuration of the resulting olefinated products is consistent with that of a proposed C-H insertion intermediate.