Syntheses and reactivity of spiro-epoxy/aziridine oxindole cores: developments in the past decade.

Spiro-epoxy/aziridine oxindole frameworks are considered as an efficient structural toolbox to obtain C3-functionalised oxindole derivatives. These 3,3'-spiro-cyclic precursors are highly susceptible towards nucleophiles owing to their inherent ring strain. Their versatile reactivity has opened many potential synthetic transformations, allowing access to bioactive molecules as well as natural products.