Synthesis of Indolines via a SmI₂ Promoted Domino Nitro Reduction–Intramolecular aza‐Michael Reaction

Abstract

A simple and straightforward synthesis of substituted indolines based on a domino nitro reduction intramolecular aza‐Michael reaction is described. The reaction employs Samarium diiodide under mild conditions for the addition of dibromoacetic acid to substituted 2‐(2‐nitrophenyl) acetaldehyde derivatives and their subsequent cyclization upon nitro group reduction to provide corresponding indoline heterocycles in good yields. This “one pot” strategy also permitted the expeditious synthesis of a 1,2,3,4‐tetrahydroquinoline, whereas the seven‐membered 2,3,4,5‐tetrahydrobenzoazepines compounds were not formed under these reaction conditions.