Lewis acid catalyzed annulation of spirocyclic donor-acceptor cyclopropanes with exo-heterocyclic olefins: access to highly functionalized bis-spirocyclopentane oxindole frameworks.


Division of Molecular Synthesis and Drug Discovery, Centre of Biomedical Research, SGPGIMS Campus, Lucknow-226014, UP, India. [Email] [Email]


Lewis acid catalyzed highly efficient [3+2] annulation of spirocyclic Donor-Acceptor cyclopropanes (DACs) with exo-heterocyclic olefins is reported to furnish various biologically relevant dispiro-2,3-dioxopyrrolidine[cyclopentane]oxindole and dispiropyrazolone[cyclopentane]oxindole frameworks. This report highlights the use of oxindole-activated spiro-DACs as potential synthons to access complex dispirocarbocyclic oxindoles via ring-enlargement of the former, with high yields and diastereoselectivity.

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