Efficient Synthesis of Pseudoindoxyls from 2-Nitrobenzylidenemalonates and Indoles

In this Letter, we have outlined a base-promoted highly efficient and mild synthetic route for constructing pseudoindoxyl derivatives, involving 2-nitrobenzylidenemalonates and indoles. This methodology enables the formation of a novel quaternary carbon center alongside a five-membered ring via Michael addition, followed by nucleophilic addition-elimination and a hydrolysis reaction in a cascade fashion. The reaction features a broad substrate scope, scalability, and excellent functional group tolerance with high yields. Additionally, postsynthetic modifications and photophysical studies demonstrate its versatility, making this elementary method a valuable tool for diverse synthetic applications involving pseudoindoxyl moieties.