Tandem Acylation and Aromatization of Vinylogous Esters: A Regiospecific Approach to Resorcinyl Ketones

This study demonstrates the direct conversion of vinylogous esters into selectively protected 6-acyl resorcinols (4-alkoxy/aryloxy-2-hydroxy arylketones) in a regiospecific manner. Resorcinyl ketones are first-time synthesized, diverging from their traditional roots, originating from non-benzenoid pool materials. Converting cyclohexenones into phenol- or resorcinol-based arylketones remains challenging due to the stability and reactivity issues of intermediate products. Addressing this critical gap, we introduce a novel strategy: sequential one-pot acylation and oxidative aromatization of vinylogous esters. This innovative approach aims to surmount the long-standing barrier, facilitating the synthesis of diverse resorcinyl ketones. Furthermore, this method proves valuable for the synthesis of functionalized diaryl ethers and in the total synthesis of bioactive natural products and drug molecules such as angolensin, isoliquiritigenin, demethylsorbicillin, ponganone VII, and ipriflavone. It is also useful for modifying bioactive acids and alcohols by introducing a resorcinol functionality in the late stage of synthesis. Synthetic analogues of oxybenzone demonstrated superior ultraviolet (UV) absorption properties, effectively covering the entire UV-A and UV-B regions, spanning from 230 to 410 nm.