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).