Photocatalytic Imidazolium Ester- and Phosphine-Mediated Radical Relay for Access to Structurally Complex Indanone-3-carboxylates

Indanone-3-carboxylates are key organic synthetic intermediates for a range of bioactive molecules. However, their efficient synthesis, particularly for structurally complex indanone-3-carboxylates, still faces challenges such as cumbersome steps and harsh conditions. Herein, we report a photocatalytic imidazolium ester- and phosphine-mediated dehydroxylative cyclization/acylation of 2-vinylbenzoic acids. This radical relay strategy enables the efficient preparation of structurally diverse indanone-3-carboxylates from readily available 2-vinylbenzoic acids and nitrogen heterocyclic carbene (NHC)-based azolium salts under mild conditions. The reaction exhibits broad substrate scope and, notably, allows facile access to carbon-cycle-fused indanone-3-carboxylate scaffolds that are challenging to obtain using conventional methods. Preliminary bioactivity assays reveal that several products possess good antifungal activity, demonstrating the potential of this method to advance the development of indanone-3-carboxylate-related bioactive molecules.