Base-promoted Conia-ene cyclization of propargyl amides
Alessandro Cerveri1, Mattia Vettori1, Andrea Serafino1
1Università di Parma, Dipartimento di Scienze Chimiche, della Vita e della Sostenibilità Ambientale, Parco Area delle Scienze 17/A, 43124 Parma, Italy. giovanni.maestri@unipr.it.
Abstract:
We report a tBuOK-promoted synthesis of 1,3-dihydro-2H-pyrrol-2-one and 4-methylenepyrrolidin-2-one systems via Conia-ene like intramolecular cyclization. The method features extremely short reaction times (5 min) and mild reaction conditions (rt), enabling the trapping of a propargyl unit by an amide enolate. An intriguing anionic chain mechanism is at work, which can trigger the isomerization of an exo-alkene giving access to the otherwise elusive endo-product.
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