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首页> 外文期刊>Chemistry: A European journal >Aerobic reduction of olefins by in situ generation of diimide with synthetic flavin catalysts
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Aerobic reduction of olefins by in situ generation of diimide with synthetic flavin catalysts

机译：用合成黄素催化剂通过原位生成二酰亚胺来需氧还原烯烃

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摘要

A versatile reducing agent, diimide, can be generated efficiently by the aerobic oxidation of hydrazine with neutral and cationic synthetic flavin catalysts 1 and 2. This technique provides a convenient and safe method for the aerobic reduction of olefins, which proceeds with 1 equiv of hydrazine under an atmosphere of O_2 or air. The synthetic advantage over the conventional gas-based method has been illustrated through high hydrazine efficiency, easy and safe handling, and characteristic chemoselectivity. Vitamin B_2 derivative 6 acts as a highly practical, robust catalyst for this purpose because of its high availability and recyclability. Association complexes of 1b with dendritic 2,5-bis(acylamino)pyridine 15 exhibit unprecedented catalytic activities, with the reduction of aromatic and hydroxy olefins proceeding significantly faster when a higher-generation dendrimer is used as a host pair for the association catalysts. Contrasting retardation is observed upon similar treatment of non-aromatic or non-hydroxy olefins with the dendrimer catalysts. Control experiments and kinetic studies revealed that these catalytic reactions include two independent, anaerobic and aerobic, processes for the generation of diimide from hydrazine. Positive and negative dendrimer effects on the catalytic reactions have been ascribed to the specific inclusion of hydrazine and olefinic substrates into the enzyme-like reaction cavities of the association complex catalysts.
机译：通过用中性和阳离子合成黄素催化剂1和2对肼进行好氧氧化，可以有效地生成通用的还原剂二酰亚胺。该技术为烯烃的好氧还原提供了一种方便而安全的方法，该方法以1当量的肼进行在O_2或空气中。高肼效率，简便安全的处理方法以及独特的化学选择性已证明了其与传统的基于气体方法的综合优势。维生素B_2衍生物6由于具有很高的利用率和可回收性，因此可作为一种高度实用，坚固的催化剂。 1b与树枝状2，5-双（酰基氨基）吡啶15的缔合配合物表现出空前的催化活性，当将更高级的树枝状大分子用作缔合催化剂的主体对时，芳烃和羟基烯烃的还原过程明显加快。在用树枝状聚合物催化剂对非芳族或非羟基烯烃进行类似处理时观察到相反的延迟。对照实验和动力学研究表明，这些催化反应包括由肼生成二酰亚胺的两个独立的厌氧和好氧过程。树枝状大分子对催化反应的正面和负面影响已归因于将肼和烯烃底物特定地包含在缔合配合物催化剂的酶样反应腔中。

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