Department of Chemistry, The State University of New York at Buffalo, Buffalo, NY 14260 (USA), Fax: (+1) 716-645-6963.
Chemistry. 2013 Sep 16;19(38):12771-7. doi: 10.1002/chem.201301800. Epub 2013 Jul 22.
Enamines and enamides are useful synthetic intermediates and common components of bioactive compounds. A new protocol for their direct synthesis by a net alkene C-H amination and allylic amination by using catalytic Cu(II) in the presence of MnO2 is reported. Reactions between N-aryl sulfonamides and vinyl arenes furnish enamides, allylic amines, indoles, benzothiazine dioxides, and dibenzazepines directly and efficiently. Control experiments further showed that MnO2 alone can promote the reaction in the absence of a copper salt, albeit with lower efficiency. Mechanistic probes support the involvement of nitrogen-radical intermediates. This method is ideal for the synthesis of enamides from 1,1-disubstituted vinyl arenes, which are uncommon substrates in existing oxidative amination protocols.
烯胺和烯酰胺是有用的合成中间体，也是生物活性化合物的常见组成部分。本文报道了一种新的方法，即在 MnO2 存在下，使用催化量的 Cu(II)，通过净烯烃 C-H 胺化和烯丙基胺化，直接合成这些化合物。N-芳基磺酰胺与乙烯基芳烃之间的反应可直接、有效地生成烯酰胺、烯丙基胺、吲哚、苯并噻嗪二氧化物和二苯并氮杂䓬。控制实验进一步表明，MnO2 可以在没有铜盐的情况下单独促进反应，尽管效率较低。机理探针支持氮自由基中间体的参与。该方法非常适合于 1,1-二取代乙烯基芳烃的烯酰胺合成，这是现有氧化胺化方法中不常见的底物。
