Syntheses and Applications of Spirocyclopropyl Oxindoles: A Decade Review
Akash P. Sakla, Pritish Kansal, Nagula Shankaraiah
Abstract
Spirocyclopropyl oxindole represents an emerging framework by unique amalgamation of versatile 2‐oxindole motif and highly strained cyclopropane unit. This scaffold is remarkable for its diverse medicinal and synthetic applications. The present review delivers a comprehensive overview of the strategies to afford spirocyclopropyl oxindoles and their potential synthetic transformations. The syntheses of spirocyclopropyl oxindoles have been described based on the type of precursors, including isatin, 3‐alkenyl oxindole, diazooxindole, oxindole, and 3‐chlorooxindole. Besides, the utility of different cyclopropanation reagents like sulfur ylide, MBH‐carbonate, carbenoid, vinyl selenone, etc. have also been emphasized. Furthermore, various ring‐expansion/opening reactions of spirocyclopropane oxindoles using dipolarophiles/nucleophiles have critically been illustrated.