Supramolecular Catalyst for Aldehyde Hydrogenation and Tandem Hydroformylation-Hydrogenation
Supramolecular Catalyst for Aldehyde Hydrogenation and Tandem Hydroformylation-Hydrogenation
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DOI：
10.1002/anie.200903620
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Breit, Bernhard
中科院分区：
文献类型：
--
作者：
Diab, Lisa;Smejkal, Tomas;Breit, Bernhard
在过去的几年里，超分子催化这一新兴领域取得了许多令人瞩目的进展。例如，通过自组装形成的大量潜在催化剂现在可以通过简单地改变组成构件以方便的方式变化。[1]这一发展为设计合成催化剂以模拟天然酶的底物识别和活化铺平了道路。改进的催化活性和选择性，以及发现新的合成有用的转化。[2]烯烃加氢裂化是目前在均相催化下进行的主要工业过程之一。[3]然而，加氢甲酰化反应的主要产物--β-内酰胺作为最终产物实际上并不重要。醛通常转化为醇，其可用作溶剂以及增塑剂和洗涤剂的原料。氢化通常在单独的步骤中进行;然而，醇也可以通过使用钴催化剂作为串联的加氢甲酰化-氢化产物来生产，尽管产率较低并且在苛刻的条件下。[4]尽管在这一领域做出了相当大的努力，但在温和条件下进行化学和区域选择性加氢以得到醇产品的最终目标仍然难以实现。[5]配体-金属双功能催化是近年来发展起来的一种有价值的碳氧双键加氢方法。关键的机械步骤涉及一个独特的协调，外层还原，其中基板不协调的金属之前，添加氢。[6，7]我们推断，开发基于中性氢化铑/膦络合物的新型氢化催化剂（优先氢化催化剂）用于在温和条件下氢化，将是实现有效串联加氢甲酰化-氢化的必要的第一步。
In the past few years, many remarkable advances have been made in the emerging field of supramolecular catalysis. For example, large numbers of potential catalysts formed by selfassembly can now be varied in an expedient way by simply changing the constituent building blocks.[1] This development paves the way for the design of synthetic catalysts to mimic natural enzymes in substrate recognition and activation. Improved catalytic activity and selectivity should result, as well as the discovery of new synthetically useful transformations.[2]The hydroformylation of alkenes is one of the major industrial processes currently carried out under homogeneous catalysis.[3] Nevertheless, aldehydes—the primary products of the hydroformylation—have virtually no importance as final products. Aldehydes are typically converted into alcohols, which find application as solvents and as raw materials for plasticizers and detergents. The hydrogenation is usually conducted in a separate step; however, alcohols can also be produced as tandem hydroformylation–hydrogenation products through the use of cobalt catalysts, albeit in lower yield and under harsh conditions.[4] Despite considerable efforts in this area, the final goal of chemo-and regioselective hydroformylation to give alcohol products under mild conditions remains elusive.[5] Ligand–metal bifunctional catalysis has recently become a valuable method for the hydrogenation of the C= O double bond. The key mechanistic step involves a unique concerted, outer-sphere reduction in which the substrate does not coordinate to the metal prior to the addition of dihydrogen.[6, 7] We reasoned that the development of a novel hydrogenation catalyst based on a neutral rhodium hydride/phosphine complex (privileged hydroformylation catalyst) for hydroformylation under mild conditions would be the necessary first step toward an efficient tandem hydroformylation–hydrogenation.