Synthesis of oxindoles via reductive CO2 fixation

Abstract

The synthesis of 3-aryl-3-hydroxy-2-oxindoles, which are a structural motif found in various natural products and pharmaceutically active compounds, was conducted via reductive coupling of (2-aminophenyl)(aryl)methanone derivatives and CO₂ as a key step. The conditions employing Mg with chlorotrimethylsilane in DMA are the best for the reductive coupling. The reductive coupling and acid-catalyzed lactam formation can be performed in a one-pot reaction to give the oxindoles.