Sulfated tungstate: a highly efficient catalyst for transamidation of carboxamides with amines
作者:Sagar P. Pathare、Ashish Kumar H. Jain、Krishnacharya G. Akamanchi
DOI:10.1039/c3ra00127j
日期:——
An environmentally benign protocol for the transamidation of carboxamides with amines using sulfated tungstate, as a heterogeneous catalyst, has been developed. The method has been successfully applied to the synthesis of a wide range of aromatic and aliphatic amides and phthalimides. Efficient transformation, mild reaction conditions, easy product isolation and the potential reusability of the catalyst
A substituent- and temperature-controllable NHC-derived zwitterionic catalyst enables CO<sub>2</sub> upgrading for high-efficiency construction of formamides and benzimidazoles
作者:Zhaozhuo Yu、Zhengyi Li、Lilong Zhang、Kaixun Zhu、Hongguo Wu、Hu Li、Song Yang
DOI:10.1039/d1gc01897c
日期:——
zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%–98%). The electronic effect of the introduced substituent
近年来,将温室气体CO 2化学催化升级为有价值的化学品和生物燃料引起了广泛关注。在已报道的方法中,CO 2与胺的N-甲酰化由于其在构建含N 线性和环状骨架方面的多功能性而具有重要意义。这里,稳定的N-杂环卡宾-羧基加合物(NHC-CO 2)中制备的轻便和可作为用于高效CO可回收两性离子催化剂2还原升级经由任一Ñ -formylation或另外的耦合用温和的条件下环化(25 °C, 1 atm CO 2) 使用氢硅烷作为氢源。超过 30 种不同的烷基和芳香胺可以转化为相应的甲酰胺或苯并咪唑,产率显着(74%–98%)。发现引入的取代基对NHC-CO 2的电子效应明显影响两性离子催化剂的热稳定性和亲核性,这与其催化活性直接相关。此外,NHC-CO 2可以通过在特定温度下原位脱羧来提供CO 2,这取决于引入的取代基类型。实验和计算研究表明,NHC-CO 2上的羧基物质不仅是亲核中心,而且还是在氢化硅烷化过程中快速捕获或替代环境
Consecutive Lossen rearrangement/transamidation reaction of hydroxamic acids under catalyst- and additive-free conditions
The Lossenrearrangement is a classic process for transforming activated hydroxamic acids into isocyanate under basic or thermal conditions. In the current report we disclosed a consecutive Lossenrearrangement/transamidation reaction in which unactivated hydroxamic acids were converted into N-substituted formamides in a one-pot manner under catalyst- and additive-free conditions. One feature of this
An attractive route to transamidation catalysis: Facile synthesis of new o-aryloxide-N-heterocyclic carbene ruthenium(II) complexes containing trans triphenylphosphine donors
作者:Muthukumaran Nirmala、Govindan Prakash、Periasamy Viswanathamurthi、Jan Grzegorz Malecki
DOI:10.1016/j.molcata.2015.03.015
日期:2015.7
Well-defined robust ruthenium(II) complexes 3a-d bearing o-aryloxide-N-heterocyclic carbene ligands with different wingtip substituents (3a (R= Me), 3b (R= Ph), 3c (R= Pr-i) and 3d (R= Mes)) in the imidazole ring were synthesized in good yields by the reaction of imidazolium proligands with metal precursor [RuHCl(CO)(PPh3)(3)] by transmetallation from the corresponding silver carbene complexes. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. The molecular structure of the complex 3a was identified by means of single-crystal X-ray diffraction analysis, which revealed that the complexes possess a distorted octahedral geometry. In order to explore the catalytic potential of the synthesized complexes, all the four [Ru-NHC] complexes [3a-d] were tested as catalysts for transamidation of carboxamides with amines. Notably, the complex 3a was found to be very efficient and versatile catalyst toward transamidation of a wide range of amides with amines. (C) 2015 Elsevier B.V. All rights reserved.
<i>In situ</i> activation of COOH-functionalized ZIF-90-enabled reductive CO<sub>2</sub><i>N</i>-formylation
作者:Kaixun Zhu、Yuncong Li、Zhengyi Li、Yixuan Liu、Hongguo Wu、Hu Li
DOI:10.1039/d2cc04643a
日期:——
prepared for efficient CO2 adsorption and activation to undergo reductive N-formylation with a wide range of amines (15 examples) to furnish N-formamides (78–94% yields). The –COO− species generated by an in situ interaction with amine acts as a key species for activating hydrosilane to capture CO2, and remarkably facilitates a cascade C–N coupling and hydrogenation process. Our findings show a facile strategy
一种用 COOH 功能化并具有多孔结构的非均相 ZIF-90 基催化剂很容易制备,用于有效的 CO 2吸附和活化,以与多种胺(15 个实例)进行还原N-甲酰化,以提供N-甲酰胺(78– 94% 的收率)。通过与胺原位相互作用产生的 –COO –物种作为激活氢硅烷以捕获 CO 2的关键物种,并显着促进级联 C-N 偶联和氢化过程。我们的研究结果显示了一种简便的策略,可以合理构建用于还原 CO 2增值的稳健活性位点。