Bioinspired Synthesis of Pulvinic Acids Including Xerocomic Acid and Fluorescence Properties of Bis‐lactone Intermediates

Abstract

A set of representative pulvinic acids were synthesised using a bioinspired strategy. Terphenyl‐quinones (polyporic acid scaffold) were prepared via sequential Suzuki‐Miyaura couplings allowing access to unsymmetrically substituted derivatives in a one‐pot protocol. Subjected to the action of acetic anhydride and DMSO, quinones were converted into bis‐lactone intermediates. Methanolysis and deprotection achieved the total syntheses of the corresponding pulvinic acids. Following this general strategy, symmetrical pulvinic, atromentic, variegatic acids and unsymmetrical congener pinastric, iso‐pinastric, xerocomic and iso‐xerocomic acids were prepared in fair yields. Fluorescence properties were observed for the bis‐lactone intermediates and, as a complement to this synthetic work, optical properties were measured, and fluorescence quantum yields were determined for the bis‐lactone pigments.