An efficient, visible light Ru(bpy)₃Cl₂-catalyzed method for the preparation of 2,3-dihydrofurans is reported. This approach employs 2-bromoketoesters as radical precursors and alkyl enol ethers as acceptors. The photoredox cycle furnishes an oxonium ion that is captured by an internal nucleophile to render the corresponding dihydrofurans. Moreover, the obtained products contain a versatile acetal moiety at C-2, allowing its transformation into a diverse variety of heteroaromatic and nonaromatic compounds. This method could serve as an important tool in the synthesis of complex tetrahydro- and dihydrofurans as well as heteroaromatic structures.

中文翻译：

---

可见光钌催化光氧化还原获得取代二氢呋喃

报道了一种高效的可见光Ru(bpy) ₃ Cl ₂催化制备2,3-二氢呋喃的方法。该方法使用 2-溴酮酯作为自由基前体，使用烷基烯醇醚作为受体。光氧化还原循环提供了一个氧鎓离子，该氧鎓离子被内部亲核试剂捕获以提供相应的二氢呋喃。此外，所获得的产品在 C-2 处含有一个通用的缩醛部分，使其能够转化为多种杂芳族和非芳族化合物。该方法可作为合成复杂四氢呋喃和二氢呋喃以及杂芳烃结构的重要工具。