Review of Synthesis of Spiro Heterocyclic Compounds from Isatin

Isatin is an essential building block in organic synthesis and shows various biological activities. The most attractive application of isatin in organic synthesis is undoubtedly in the highly reactive C-3 carbonyl group, which is a prochiral center as well. The construction of a spiroheterocyclic framework has always been a challenging endeavor for synthetic organic chemists as it frequently requires synthetic design based on specific strategies. This review gives a short summary of the advances in the use of isatin in the synthesis of various spiroheterocyclic compounds through multicomponent reactions and 1,3-dipolar cycloaddition reactions.