已经实现了取代的2-芳基咪唑并[1,2- a ]吡啶对N-甲基吗啉氧化物的钒催化氧化偶联,N-甲基吗啉既是偶联剂又是氧化剂。该反应用于各种取代的咪唑并[1,2- a ]吡啶和吲哚底物,产率高达90%。机理研究表明该反应可以通过曼尼希型过程进行。这项工作证明了如何将氧化氨基甲基化用作将叔胺引入杂环的有用方法,从而为常规曼尼希型反应提供了另一种方法。
Vanadyl Acetylacetonate Catalyzed Methylenation of Imidazo[1,2-<i>a</i>]pyridines by Using Dimethylacetamide as a Methylene Source: Direct Access to Bis(imidazo[1,2-<i>a</i>]pyridin-3-yl)methanes
imidazo[1,2‐a]pyridines using dimethylacetamide (DMA) as methylene source in the presence of vanadyl acetylacetonate [VO(acac)2] as the catalyst and iodobenzene diacetate as the oxidant. The reaction involves coupling of sp3‐ and sp2‐hybridized carbons and proceeds through the formation of an iminium ion. A wide variety of imidazo[1,2‐a]pyridines were converted to bis(imidazo[1,2‐a]pyridin‐3‐yl)methanes
已经开发了一种有效的方案,用于在乙酰丙酮氧钒[VO(acac)2 ]为催化剂和碘代乙酸二苯酯为氧化剂的情况下,使用二甲基乙酰胺(DMA)作为亚甲基来源的咪唑并[1,2- a ]吡啶的甲基化。该反应涉及sp 3-和sp 2-杂化碳的偶合,并通过形成亚胺离子进行。多种咪唑并[1,2一]吡啶转化为双(咪唑并[1,2一]吡啶-3-基)甲烷在良好至优异的产量。克级反应证明了放大工艺的潜力。