Metal-free syntheses of oxindole derivatives via a benzoylation/substitution/desulfonylation/cyclization cascade†
Abstract
A benzoylation/substitution/desulfonylation/cyclization cascade reaction giving oxindole derivatives was discovered. The reaction used aromatic aldehydes and N-alkyl-N-(phenylsulfonyl)methacrylamides as starting materials, and proceeded under mild conditions without using toxic metal catalysts. 3-Methyl-3-aroyloxindole derivatives were formed in good yields.