Efficient Tandem Synthesis of Methyl Esters and Imines by Using Versatile Hydrotalcite-Supported Gold Nanoparticles
作者:Peng Liu、Can Li、Emiel J. M. Hensen
DOI:10.1002/chem.201202077
日期:2012.9.17
hydrotalcite (HT)‐supportedgold nanoparticle (AuNP) catalysts have been developed for the aerobic oxidative tandemsynthesis of methyl esters and imines from primary alcohols catalyzed under mild and soluble‐base‐free conditions. The catalytic performance can be fine‐tuned for these cascade reactions by simple adjustment of the Mg/Al atomic ratio of the HT support. The one‐pot synthesis of methyl esters
已经开发了高效的碱性水滑石(HT)负载的金纳米颗粒(AuNP)催化剂,用于在温和且无碱的条件下,由伯醇催化好氧氧化串联合成甲酯和亚胺。可以通过简单调节HT载体的Mg / Al原子比来微调这些级联反应的催化性能。一锅法合成甲酯得益于高碱度(Mg / Al = 5),而适度的碱度大大提高了亚胺选择性(Mg / Al = 2)。到目前为止,这些催化剂的性能优于先前报道的AuNP催化剂。动力学研究表明AuNP和表面碱性位点之间的协同增强,不仅有利于起始醇的氧化,而且有利于串联反应的后续步骤。据我们所知,
Erbium(III) Triflate: A Valuable Catalyst for the Synthesis of Aldimines, Ketimines, and Enaminones
作者:Renato Dalpozzo、Antonio De Nino、Monica Nardi、Beatrice Russo、Antonio Procopio
DOI:10.1055/s-2006-926378
日期:——
and enaminones can be obtained under erbium(III) triflate catalysis. The reaction mechanism is that typical of imine synthesis. The role of the catalyst is demonstrated for the synthesis of aromatic imines. In contrast to CeCl 3 /NaI addition to unsaturated aldehydes, which results in Michael addition, no Michael adduct was observed under erbium(III) triflate catalysis.
The first example of a base‐metal‐catalyzed homogeneous hydrogenative coupling of nitriles and amines to selectively form secondary cross‐imines is reported. The reaction is catalyzed under mild conditions by a well‐defined (iPr‐PNP)Fe(H)Br(CO) pincer pre‐catalyst and catalytic tBuOK.
Formation of imines by selective gold-catalysed aerobic oxidative coupling of alcohols and amines under ambient conditions
作者:Søren Kegnæs、Jerrik Mielby、Uffe V. Mentzel、Claus H. Christensen、Anders Riisager
DOI:10.1039/c0gc00126k
日期:——
imines by aerobicoxidative coupling of mixtures of alcohols and amines was studied using gold nanoparticles supported on titanium dioxide, TiO2, as a heterogeneous catalyst. The reactions were performed at ambientconditions (room temperature and atmospheric pressure) and occurred with excellent selectivity (above 98%) at moderate conversion under optimized conditions. The effect of catalytic amounts