Blue light-promoted photolysis of aryldiazoacetates
作者:Igor D. Jurberg、Huw M. L. Davies
DOI:10.1039/c8sc01165f
日期:——
Aryldiazoacetates can undergo photolysis under blue light irradiation (460–490 nm) at room temperature and under air in the presence of numerous trapping agents, such as styrene, carboxylic acids, amines, alkanes and arenes, thus providing a straighforward and general platform for their mild functionalization.
Elevated Catalytic Activity of Ruthenium(II)-Porphyrin-Catalyzed Carbene/Nitrene Transfer and Insertion Reactions with N-Heterocyclic Carbene Ligands
作者:Ka-Ho Chan、Xiangguo Guan、Vanessa Kar-Yan Lo、Chi-Ming Che
DOI:10.1002/anie.201309888
日期:2014.3.10
characterized. Owing to the strong donor strength of axial NHC ligands in stabilizing the trans MCRR′/MNR moiety, these complexes showed unprecedently high catalytic activity towards alkenecyclopropanation, carbene CH, NH, SH, and OH insertion, alkeneaziridination, and nitrene CH insertion with turnover frequencies up to 1950 min−1. The use of chiral [Ru(D4‐Por)(BIMe)2] (1 g) as a catalyst led to
Ruthenium nanoparticles supported on non-cross-linked soluble polystyrene were prepared by reacting [RuCl
2
(C
6
H
5
CO
2
Et)]
2
with polystyrene in open air. They effectively catalyze intra- and intermolecular carbenoid insertion into C—H and N—H bonds, alkene cyclopropanation, and ammonium ylide/[2,3]-sigmatropic rearrangement reactions. This supported ruthenium catalyst is much more reactive than [RuCl
2
(p-cymene)]
2
and Ru(Por)CO] for catalytic intermolecular carbenoid C—H bond insertion into saturated alkanes. By using a-diazoacetamide as a substrate for intramolecular carbenoid C—H insertion, the supported ruthenium catalyst can be to recovered and reused for ten successive iterations without significant loss of activity.
Rhodium Chemzymes: Michaelis−Menten Kinetics in Dirhodium(II) Carboxylate-Catalyzed Carbenoid Reactions
作者:Michael C. Pirrung、Hao Liu、Andrew T. Morehead
DOI:10.1021/ja011599l
日期:2002.2.1
bind both to the free catalyst and to the catalyst-substrate complex. Substrate inhibition can also be exhibited by diazocompounds bearing these groupings in addition to the diazogroup. The analysis of inhibition shows that the active catalyst uses only one of its two coordination sites at a time for catalysis. Some ketones exhibit the interesting property that they selectively bind to the catalyst-substrate
羧酸铑介导的重氮酮反应,包括环丙烷化、CH 插入和芳香 CC 双键加成/电环开环遵循饱和 (Michaelis-Menten) 动力学。铑的轴向配体,包括芳烃和路易斯碱,如腈、醚和酮,通过混合动力学抑制机制抑制这些反应,这意味着它们可以与游离催化剂和催化剂-底物复合物结合。除了重氮基团之外,带有这些基团的重氮化合物也可以表现出底物抑制作用。抑制分析表明,活性催化剂一次仅使用其两个配位点之一进行催化。一些酮表现出有趣的特性,即它们选择性地与催化剂-底物复合物结合。无论连接单元或反应烯烃的环境如何,来自具有相似重氮酮的不同类型反应的动力学常数的相似性表明,速率决定步骤是生成铑卡宾。一种用于不对称合成的非常有用的羧酸铑催化剂,Rh(2)(DOSP)(4),显示出比非手性催化剂稍慢的动力学参数,这意味着该催化剂的对映选择性是基于减缓其中一个对映体面的反应。反应物,而不是任何类型的配体加速催化。一系列从
Combined Experimental and Computational Studies of Heterobimetallic Bi−Rh Paddlewheel Carboxylates as Catalysts for Metal Carbenoid Transformations
作者:Jo̷rn Hansen、Bo Li、Evgeny Dikarev、Jochen Autschbach、Huw M. L. Davies
DOI:10.1021/jo900998s
日期:2009.9.4
The catalytic activity of heterobimetallic Bi−Rh paddlewheel carboxylate complexes has been evaluated for the first time in the context of metal carbenoid chemistry. The Bi−Rh carboxylate complexes were found to effectively catalyze both cyclopropanation reactions and C−H insertions as well as reactions involving ylide intermediates with similar selectivity profiles to analogous dirhodium complexes