A review on 2-arylidene-1,3-indanediones: preparation and applications to the synthesis of diverse spirocyclic compounds

Arylidene-1,3-indanediones are readily available 1,3-dipolarophile and dienophiles that have been frequently used in numerous synthetic processes to produce a variety of indanone-fused heterocycles. It has been regarded as a fundamental building block in organic synthesis. Moreover, indanone-fused heterocycles are well-known heterocyclic scaffolds found in a wide range of alkaloids and have significant biological effects. As a result, there is growing interest in employing 2-arylidene-1,3-indanedione-based multi-component reactions to construct versatile spirocyclic scaffolds rapidly. It has been effectively utilized as a precursor by taking advantage of its reactivity. The majority of the studies discussed involve straightforward reactions with easily accessible starting materials that lead to intricate molecular structures. The present review aims to highlight the preparation of 2-arylidene-1,3-indanediones and multi-component reactions of 2-arylidene-1,3-indanediones to produce diverse spirocyclic compounds. The reaction characteristics, key reaction mechanisms, and experimental results are briefly discussed. Finally, future developments in the diverse reactions of arylidene-1,3-indanediones are also prospected.