酰胺加氢成胺是重要的反应,但是需要高温和H 2压力是一个问题。在温和的反应条件下(低于30 bar H 2和70°C)有效的催化剂尚未见报道。在此,通过使用Pt-V双金属催化剂首次实现了酰胺的温和氢化。酰胺氢化,在70°C下1 bar H 2或5 bar H 2下使用双金属催化剂达到室温。温和的反应条件能够在抑制芳烃氢化的同时,将各种酰胺高度选择性地氢化为相应的胺。催化剂表征表明,双金属催化剂催化活性的起源是亲氧性的V-修饰的Pt纳米颗粒,其直径为2 nm。
Pd(II)-catalyzed synthesis of indoles from α-aryloxime O-pentafluorobenzoates via intramolecular aromatic C–H amination
作者:Shunsuke Chiba、Line Zhang、Stephen Sanjaya、Gim Yean Ang
DOI:10.1016/j.tet.2010.05.029
日期:2010.7
α-Aryl-α-aminocarbonyloxime O-pentafluorobenzoates are found to be promising precursors for synthesis of 2,3-disubstituted indole derivatives catalyzed by PdCl2(MeCN)2 in the presence of MgO as a base. The reaction is supposed to proceed viaintramolecular aromatic C–H amination of a vinyl nitrene–palladium intermediate.
General Synthesis of Fully Substituted 4-Aminooxazoles from Amides and 1,4,2-Dioxazol-5-ones Based on Amide Activation and Umpolung Process
作者:Yunxiang Weng、Lin Min、Lidong Shan、Hongchen Li、Xinyan Wang、Yuefei Hu
DOI:10.1021/acs.joc.0c02015
日期:2021.1.1
A general and efficientsynthesis of fully substituted 4-aminodixazoles was developed based on the strategies of amide activation and umpolung reaction. In this method, 1,4,2-dioxazol-5-ones were introduced as a rare type of umpolung reagent bearing a nucleophilic N-atom that could be used well together with the activating agent Tf2O. Because 1,4,2-dioxazol-5-ones played triple roles as an umpolung
We have developed an organocatalyticasymmetricMichaelreaction of acylsilane through the selection of acylsilane substrates and organocatalysts, thus creating a rare example of acylsilane α-alkylation with a chiral guanidine catalyst, which afforded products in good yields and high stereoselectivity. The corresponding adducts described here have also been demonstrated to be useful in the synthesis