Rhodium- and Palladium-Catalyzed 1,5-Substitution Reactions of 2-En-4-yne Acetates and Carbonates with Organoboronic Acids
作者:Muhammed Üçüncü、Erman Karakuş、Melih Kuş、Gürkan Eray Akpınar、Özge Aksın-Artok、Norbert Krause、Sıla Karaca、Nuran Elmacı、Levent Artok
DOI:10.1021/jo200201r
日期:2011.8.5
would not allow such coordinative interaction to occur. The palladium-catalyzed method, which proceeds through formation of the σ-vinylallenylpalladium intermediate, B, is suitable for both the (E)- and (Z)-configured enyne carbonates and appears to have a wider scope for both organoboronic acids and enyne substrates. The palladium-catalyzed reaction of an enantiomerically enriched enyne carbonate proceeded
研究了两种方法,包括铑催化的2-en-4-yne乙酸盐的铑催化反应和钯催化的2-en-4-yne碳酸酯与有机硼酸的反应。两者都仅提供(E)-构型的乙烯基烯。与乙酸酯基团中的铑的协调相互作用从alkenylrhodium中间促进了δ-消除的Rh(I)-OAc的II在两个顺式和反模式,与顺式β-消除是主要路径。DFT计算表明,该中间体(II)的构象异构体可通过syn生成(E)构型的乙烯基丙二烯产物。-消除模式,在能量上是最有利的构想者。铑催化的方法不适用于涉及(E)-构型的烯炔乙酸酯的反应,因为衍生自相应的(E)-烯炔乙酸酯的烯基铑中间体的几何形状将不允许这种配位相互作用发生。通过形成σ-乙烯基烯丙基钯中间体B进行的钯催化方法适用于(E)和(Z)构型的碳酸炔烃,似乎对有机硼酸和炔烃底物的适用范围更广。对映体富集的碳酸炔炔的钯催化反应进行消旋。