Synthesis of spiro-fused heterocyclic scaffolds through multicomponent reactions involving isatin

Isatin has been utilized in many heterocyclic preparations and considered as an important building block in organic synthesis. There is a wide range of multi-component reactions that include isatin in the synthesis of heterocyclic compounds. This review highlights the advances in the use of isatin as starting material in the synthesis of various organic compounds and drugs during the period from 2012 to 2015.