Propagative isatin in organic synthesis of spirooxindoles through catalysis

Oxindole (indoline-2, 3-dione) has been utilized to a great extent in heterocyclic scaffold syntheses as a futuristic medication and is considered a prominent building block used in organic synthesis. Herein, oxindole promotes multi-component reactions w.r.t. initiative candidates for the formation of spirooxindole scaffolds. This review reflects the advances of oxindole in organic synthesis as a selected starting material in the formation of spirooxindoles from 2015 to 2022. Remarkable spirooxindoles have isolated distinct genus (plants and animals), and their origins have significant recreation opportunities in medicinal chemistry. Spiro-skeleton compounds have cyclic structures which are fused on a central carbon (sp3 hybridized), obtaining interesting conformational features to favour anti-proliferation evaluation. The obvious reaction mechanisms involve the plausible reactivity of the reactants, the catalyst interaction, and the cyclization to produce spirooxindole derivatives.