Total Syntheses of the Isomeric Aglain Natural Products Foveoglin A and Perviridisin B: Selective Excited‐State Intramolecular Proton‐Transfer Photocycloaddition

Abstract

Selective excited‐state intramolecular proton‐transfer (ESIPT) photocycloaddition of 3‐hydroxyflavones with trans, trans‐1,4‐diphenyl‐1,3‐butadiene is described. Using this methodology, total syntheses of the natural products (±)‐foveoglin A and (±)‐perviridisin B were accomplished. Enantioselective ESIPT photocycloaddition using TADDOLs as chiral hydrogen‐bonding additives provided access to (+)‐foveoglin A. Mechanistic studies have revealed the possibility for a photoinduced electron‐transfer (PET) pathway.

Photochemical Rearrangements in Heterocyclic Chemistry

“…Enantioselective HAT has also been carried out recently. [45] A study of Xia et al showed the possibility to use 3-hydroxyquinolinones instead of 3-hydroxychromenones to make this photoreaction. [46] Natural compounds can be synthetized through photoinduced 1,5-HAT.…”