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
“On water”-promoted direct alkynylation of isatins catalyzed by NHC–silver complexes for the efficient synthesis of 3-hydroxy-3-ethynylindolin-2-ones
作者:Xiao-Pu Fu、Li Liu、Dong Wang、Yong-Jun Chen、Chao-Jun Li
DOI:10.1039/c0gc00807a
日期:——
The direct alkynylation of isatins catalyzed by NHCâAg complexes via the activation of alkyne CâH bond on water was developed for the efficient synthesis of 3-hydroxy-3-ethynylindolin-2-ones under an air atmosphere. A remarkable rate-enhancement by water in the aqueous heterogeneous system was observed.
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).