Light-Stable Silver N-Heterocyclic Carbene Catalysts for the Alkynylation of Ketones in Air
作者:Faïma Lazreg、Mathieu Lesieur、Andrew J. Samson、Catherine S. J. Cazin
DOI:10.1002/cctc.201500869
日期:2016.1
N‐Heterocyclic carbene (NHC) silver(I) complexes were employed efficiently in the alkynylation of ketones. These cationic complexes were highly active and efficient under mild conditions and in air without the need for an additive. The mechanism of this transformation was investigated. Experiments suggest that the formation of a silver acetylide key intermediate and the release of one ligand from the
Synthesis of 3-ethynyl-3-hydroxy-2-oxindoles and 3-hydroxy-3-(indol-3-yl) indolin-2-ones using CuWO4 nanoparticles as recyclable heterogeneous catalyst in aqueous medium
acetylenes (spC-H activation) and selective synthesis of 3-hydroxy-3-(indol-3-yl) indolin-2-ones and 3,3′-bis(indolyl)indolin-2-ones (via Friedel-Crafts alkylation reaction) is reported in presence of CuWO4 (10 mol%) nanoparticles in aqueous medium. The catalyst was regenerated and reused up to 6 cycles without losing catalytic activity. This is the first report for the spC-H activation using CuWO4
Development of a novel octahedron rhodium complex and its application to the alkynylation of isatin derivatives
作者:Ze-ying Wu、Zhen-wei Zhang、Lin-lin Ding、Mei Xiang、Shi-yi Luo
DOI:10.1016/j.tetlet.2020.152577
日期:2020.11
A new octahedron rhodiumcomplex was synthesized, which permits the direct activation of terminal alkynes and its reaction with isatin derivatives under an air atmosphere. An excellent yield (up to 99%) was obtained at a catalyst loading of 2 mol%.
electron-deficient alkynes in comparable reaction rates and does not require any specially design ligand or expensive transition-metal catalysts. A ‘direct’ alkynylation of isatins, which uses potassium tert-butoxide to provide the desired 3-hydroxy-3-ethynyl-2-oxindoles in good to high yields, is reported. This protocol proceeds smoothly for both electron-rich and electron-deficient alkynes in comparable
A highly efficient and atom-economic methodology has been developed for the synthesis of 3-(arylethynyl)-3-hydroxyindolin-2-ones from isatins by C-H activation of arylacetylenes using a catalytic quantity of copper(I) iodide (5 mol%) and DBU (20 mol%) at 25 degrees C, affording the products in excellent yields in very short reaction time (5 min).