Rh Soaked in Polyionic Gel: An Effective Catalyst for Dehydrogenative Silylation of Ketones
作者:Carine Thiot、Alain Wagner、Charles Mioskowski
DOI:10.1021/ol0623670
日期:2006.12.1
A polyionic gel- soaked Rh catalyst allows the formation of synthetically useful diphenylsilyl ( DPS) enols under mild conditions. The reaction proceeds through dehydrogenative silylation of ketones, affording the kinetic silyl enol ether in good to excellent yields. The in situ formed DPS enols were directly involved, without purification, in one- pot aldol and Mannich condensations.
A dibenz[a,c]phenazine-supported N-heterocyclic carbene and its rhodium and iridium complexes
A new polycyclic N-heterocyclic carbene featuring a fused dibenz[a, c] phenazine moiety was generated in situ from the corresponding tetrafluoroborate salt. The synthesis and NMR data of its corresponding precursors, its sulfur adduct and dimer are reported. Complexes of type [MCl(COD)(1)] and [MCl(CO)(2)(1)] (M = Rh and Ir, 1 = 1,3-dibutyldibenzo[a, c]phenazino[11,12-d]imidazol-2-ylidene) were prepared and characterized using spectroscopic and crystallographic methods. The electron-releasing capacity of this new carbene was investigated by evaluation of its corresponding IrCl(COD) and IrCl(CO)(2) complexes by IR spectroscopy (nu(av)) and cyclic voltammetry (E-1/2). These studies revealed that the electron donicity of this ligand is comparable to that of the previously reported naphthoquinone-annulated imidazolin-2-ylidene. Some preliminary studies of the photophysical properties and catalytic activity of these metal complexes are reported. (C) 2013 Elsevier B. V. All rights reserved.
A benzothiadiazole-supported N-heterocyclic carbene and its rhodium and iridium complexes
作者:Daniela Tapu、Ossie J. Buckner、Chance M. Boudreaux、Bradley Norvell、Monica Vasiliu、David A. Dixon、Colin D. McMillen
DOI:10.1016/j.jorganchem.2016.09.016
日期:2016.11
and 0.890 Å, respectively. Complexes of type [MCl(COD)(1)] (where M = Rh and Ir) were prepared and characterized using spectroscopic and crystallographic methods. The donor strength of this new carbene was determined by IR spectroscopy (νav) and cyclic voltammetry (E1/2). Preliminary catalytic studies show that the new carbene is a suitable ligand for rhodium and iridium catalysts in the hydrosilylation
一种新的N-杂环卡宾,其包含稠合的苯并噻二唑(BTD)部分,5,7-双(1,1-二甲基乙基)-5 H-咪唑并[4,5- f ] -2,1,3-苯并噻二唑-6-亚lide(1通过使相应的四氟硼酸盐去质子化而产生)。从市售的1,2-苯二胺可以六步得到盐前体。发现该卡宾在惰性条件下是稳定的,并且通过NMR光谱充分表征。还合成并充分表征了该卡宾的硫加合物。硫酮的X射线结构分析表明,卡宾碳和硫原子分别偏离含有BTD部分和咪唑环的两个氮原子的平面0.231和0.890Å。制备了[MC1(COD)(1)]型配合物(其中M = Rh和Ir),并使用光谱和晶体学方法对其进行了表征。这种新卡宾的供体强度通过红外光谱测定(ν AV)和循环伏安法(E 1/2)。初步的催化研究表明,新的卡宾是苯乙酮氢化硅烷化中铑和铱催化剂的合适配体。