In(OTf)₃‑Catalyzed One-Pot Tandem Mannich and Conia-Ene Cyclization Reaction of <i>N</i>‑Propargyl Amido Alcohols with 1,3-Dicarbonyl Compounds: An Approach To Construct Tetrahydro‑1<i>H</i>‑pyrrolo[2,1‑<i>a</i>]isoindolone-1,1-dicarboxylate and Its Application

A one-pot tandem reaction has been developed for the synthesis of substituted tetrahydropyrroloisoindolone via Mannich reaction of N-propargyl amido alcohols with 1,3-dicarbonyl compounds followed by Conia-ene cyclization reaction in moderate to good yields catalyzed by indium­(III)­triflate [In­(OTf)3]. The reaction is highly regioselective with an exo-cyclic double bond in the pyrrolidine ring. The substituted tetrahydropyrroloisoindolone can be converted to 5H-pyrrolo­[2,1-a]­isoindol-5-one via decarboxylative aromatization reaction.