Syntheses of Z‑Iodovinylfurans and 2‑Acyl Furans via Controllable Cyclization of Ynenones

A divergent synthesis of Z-iodovinylfurans and 2-acyl furans promoted by NIS via controllable cyclization of ynenones is reported. The reaction proceeded by sequential 5-exo-dig electrophilic cyclization to intermediate 2-(iodomethylene)-2H-furanium cation D, providing a range of synthetically valuable and useful trisubstituted furan derivatives 2 and 3 in moderate to excellent yields. This approach is metal-free, mild, and atom-economic, with good selectivity and high stereoselectivity.本文报道了一种由N-碘代丁二酰亚胺（N-Iodosuccinimide, NIS）介导、通过炔烯酮可控环化反应实现的Z-碘乙烯基呋喃与2-酰基呋喃的发散合成策略。该反应经连续的5-exo-dig亲电环化过程生成中间体2-(碘亚甲基)-2H-呋喃鎓阳离子D，最终以中等至优异的收率得到一系列具有合成应用价值的三取代呋喃衍生物2与3。该方法无需金属参与，反应条件温和，具备原子经济性，且选择性良好、立体选择性优异。