Unprecedented Mechanism of an Organocatalytic Route to Conjugated Enynes with a Junction to Cyclic Nitronates
作者:Verena Streitferdt、Michael H. Haindl、Johnny Hioe、Fabio Morana、Polyssena Renzi、Felicitas von Rekowski、Alexander Zimmermann、Martina Nardi、Kirsten Zeitler、Ruth M. Gschwind
DOI:10.1002/ejoc.201801153
日期:2019.1.23
Conjugated enynes as well as cyclic nitronates are crucial building blocks for numerous natural products and pharmaceuticals. However, so far, no common and metal‐free synthetic route to both conjugated enynes and cyclic nitronates has been reported. Here, in situ NMR, labelling studies and theoretical calculations were combined to investigate the mechanism of the unusual triple bond formation towards
共轭烯炔和环状硝基化合物是众多天然产物和药物的重要组成部分。然而,到目前为止,还没有报道共轭烯炔和环状硝基化合物的常见且无金属的合成路线。在这里,原位核磁共振、标记研究和理论计算相结合,以研究不寻常的三键形成对共轭烯炔的机制。从硝基烯烃二聚体开始,首先形成异恶唑烷-2,5-二醇衍生物作为中心中间体。由此,烯炔是通过氧化、脱水和逆向 1,3-偶极环加成的组合产生的,而对于硝基,则提出了碱诱导的分子内重组。虽然可以控制产品分布并获得高硝基酸盐收率,由于聚合损失,仅获得中等至良好的烯炔产率。尽管如此,我们希望这些机理研究可以为共轭烯和硝基的有机催化或无金属制剂的进一步发展提供基础。