Photochemical Approach to Fused Quinoxaline Derivatives From Allomaltol‐Containing Terarylenes With 2‐Aminooxazole Bridge Fragment via Trapping of Unstable Cyclopentene‐1,2‐Dione Intermediates
Year: 2026
Type: article
Abstract: ABSTRACT The photochemical behavior of terarylenes bearing allomaltol and 2‐aminooxazole fragments has been investigated, providing the basis for an efficient strategy toward substituted cyclopenta[b]quinoxalines. Upon irradiation of starting compounds with 400 nm visible light, the allomaltol moiety undergoes selectively ESIPT‐induced contraction of the pyranone ring, affording highly reactive α‐hydroxycyclopentene‐1,2‐dione intermediates, as evidenced by 1 H NMR monitoring. Notably, the free amino group does not inhibit the photorearrangement, in contrast to related amino‐substituted terarylenes. In situ trapping with 1,2‐phenylenediamines affords cyclopenta[b]quinoxaline derivatives in yields of up to 87%, while phenylhydrazine gives separable E/Z hydrazones. The one‐pot protocol proceeds under mild, metal‐ and base‐free conditions.
DOI: 10.1002/jhet.70232
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W7203763191