Kreuzahler Mathis, Haberhauer Gebhard
Institut für Organische Chemie, Universität Duisburg-Essen, Universitätsstraße 7, 45117, Essen, Germany.
Angew Chem Int Ed Engl. 2020 Jun 8;59(24):9433-9437. doi: 10.1002/anie.201916027. Epub 2020 Apr 6.
Haloalkynylation reactions provide an efficient method for the simultaneous introduction of a halogen atom and an acetylenic unit. For the first time, we report a gold(I)-catalyzed haloalkynylation of aryl alkynes that delivers exclusively the cis addition product. This method enables the simple synthesis of conjugated and halogenated enynes in yields of up to 90 %. Notably, quantum chemical calculations reveal an exceptional interplay between the place of the attack at the chloroacetylene: No matter which C-C bond is formed, the same enyne product is always formed. This is only possible through rearrangement of the corresponding skeleton. Hereby, one reaction pathway proceeds via a chloronium ion with a subsequent aryl shift; in the second case the corresponding vinyl cation is stabilized by a 1,3-chlorine shift. C-labeling experiments confirmed that the reaction proceeds through both reaction pathways.
卤代炔基化反应为同时引入卤原子和炔基单元提供了一种有效方法。我们首次报道了一种金（I）催化的芳基炔烃的卤代炔基化反应，该反应仅生成顺式加成产物。该方法能够以高达90%的产率简便地合成共轭和卤代烯炔。值得注意的是，量子化学计算揭示了在氯乙炔上的进攻位置之间存在特殊的相互作用：无论形成哪个C-C键，总是形成相同的烯炔产物。这只有通过相应骨架的重排才有可能实现。在此，一条反应途径通过氯鎓离子进行，随后发生芳基迁移；在第二种情况下，相应的乙烯基阳离子通过1,3-氯迁移得以稳定。碳-13标记实验证实该反应通过两条反应途径进行。
