Ethynylbenziodoxolones (EBXs) are commonly used as radical traps in photocatalytic alkynylations. Herein, we report that aryl-substituted EBX reagents can be directly activated by visible light irradiation. They act as both oxidants and radical traps, alleviating the need for a photocatalyst in several reported EBX-mediated processes, including decarboxylative and deboronative alkynylations, the oxyalkynylation of enamides and the C−H alkynylation of THF. Furthermore, the method could be applied to the synthesis of alkynylated quaternary centers from tertiary alcohols via stable oxalate salts and from tertiary amines via aryl imines. A photocatalytic process using 4CzIPN as an organic dye was also developed for the deoxyalkynylation of oxalates.

中文翻译：

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Ethynylbenziodoxolones 的直接光激发：用于炔化反应的光催化的替代方案**

乙炔基苯并恶酮 (EBX) 通常用作光催化炔基化中的自由基陷阱。在此，我们报告了芳基取代的 EBX 试剂可以通过可见光照射直接激活。它们既充当氧化剂又充当自由基陷阱，减轻了在几个报道的 EBX 介导的过程中对光催化剂的需求，包括脱羧和脱硼炔基化、烯酰胺的氧炔基化和 THF 的 CH 炔基化。此外，该方法可用于通过稳定的草酸盐从叔醇和通过芳基亚胺从叔胺合成炔基化季铵中心。还开发了使用 4CzIPN 作为有机染料的光催化过程，用于草酸盐的脱氧炔化。