ne (II), paying particular attention to the influence of the amine nitrogen hybridisation on their catalytic behaviour. Allylpalladium complexes 9–11 containing optically pure imidazolines were synthesised and fully characterised both in solution (NMR) and the solid state (single-crystal X-ray diffraction). NMR studies showed four species in solution for complex 9 containing the unsymmetrical 1-phenylallyl
Chiral pyridylimidazolines: synthesis, arene ruthenium complexes and application in asymmetric catalysis
作者:Adam J. Davenport、David L. Davies、John Fawcett、David R. Russell
DOI:10.1039/b103175a
日期:——
Condensation of (1S,2S)-1,2-diphenylethylenediamine and 2-cyanopyridine gives the chiral pyridylimidazoline (L1), deprotonation followed by treatment with methyl iodide gives an NMe derivative (L2). The pyridylimidazolines react with [RuCl2(mes)]2 (mes = 1,3,5-trimethylbenzene) in the presence of NaSbF6 to give [RuCl(L)(mes)][SbF6] (1,2) which have been characterised by X-ray crystallography. After treatment with AgSbF6 both complexes are enantioselective catalysts for the Diels–Alder reaction of methacrolein and cyclopentadiene.
Iridium-catalyzed highly chemoselective and efficient reduction of nitroalkenes to nitroalkanes in water
作者:Dong Xu、Yang Chen、Changmeng Liu、Jiaxi Xu、Zhanhui Yang
DOI:10.1039/d1gc01907d
日期:——
An iridium-catalyzed highly chemoselective and efficient transfer hydrogenation reduction of structurally diverse nitroalkenes was realized at very low catalyst loading (S/C = up to 10000 or 20 000), using formic acid or sodium formate as a traceless hydride donor in water. Excellent functionality tolerance is also observed. The turnover number and turnover frequency of the catalyst reach as high as
在非常低的催化剂负载量(S/C = 高达 10000 或 20 000)下,使用甲酸或甲酸钠作为水中的无痕氢化物供体,实现了铱催化的高化学选择性和高效转移氢化还原结构多样的硝基烯烃。还观察到优异的功能耐受性。催化剂的周转次数和周转频率高达18 600和19 200 h -1, 分别。不需要惰性气氛保护。硝基烯烃的反应性取决于它们的取代模式,pH 值是实现完全转化和优异化学选择性的关键因素。产品的纯化通过简单的萃取实现,无需柱层析。还原过程在 10 000 S/C 比率下轻松放大到 10 g 规模。这种绿色还原在对映选择性氢化中的潜力已经得到证实。
pyridinimidazolines, Schiff bases and bipyridines, are described. These ligands are used as cocatalysts together with the procatalyst [Rh(COD)Cl]2 in the catalytic hydrosilylation of prochiral ketones with diphenylsilane. With these homogeneous in situ catalysts, optically active 1-phenylethanol is produced from acetophenone after hydrolysis of the silyl ether. The diastereomers of N-(1-phenyleth