Koh, Yunbi Yoo, Gayeon Tae, Jinsung Lee, Sanghee Lee, Ansoo 2025-09-17T02:33:32Z 2025-09-17T02:33:32Z 2025-09-16 2025-12 2052-4110 https://pubs.kist.re.kr/handle/201004/153180 A novel photocatalyst-free radical conjugate addition to 2-substituted chromones has been developed, utilizing Hantzsch esters and TMSOTf to efficiently access diverse 2,2-disubstituted chroman-4-ones under mild conditions. Mechanistic studies, including UV–vis spectroscopy and 1H NMR titration, indicate that the reaction proceeds via an electron donor–acceptor (EDA) complex, which is formed in situ through the reaction of TMSOTf with chromones to generate 4-siloxy-1-benzopyrylium salts. This versatile method enables late-stage functionalization of natural chromones, affording structurally diverse scaffolds with promising biological activity. The resulting chroman-4-one derivatives suppress cGAMP-induced immune responses in ISRE assays, whereas their parent chromones enhance these responses. These results highlight chroman-4-ones as promising immunosuppressive scaffolds for therapeutic development. English Royal Society of Chemistry Radical conjugate addition to 2-substituted chromones via an electron donor–acceptor complex Article 10.1039/d5qo00933b 1 Organic Chemistry Frontiers, v.12, no.23, pp.6519 - 6527 Organic Chemistry Frontiers 12 23 6519 6527 N scie scopus 001562968900001 Chemistry, Organic Chemistry Article SCAFFOLD ACTIVATION