Immobilized Di(hydroperoxy)propane Adducts of Phosphine Oxides as Traceless and Recyclable Oxidizing Agents
Immobilized Di(hydroperoxy)propane Adducts of Phosphine Oxides as Traceless and Recyclable Oxidizing Agents
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DOI：
10.1016/j.apsusc.2023.157333
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发表时间：
2023-04
影响因子：
6.7
通讯作者：
John C. Hoefler;Anh Vu;Arturo J. Perez;J. Blümel
中科院分区：
文献类型：
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作者：
John C. Hoefler;Anh Vu;Arturo J. Perez;J. Blümel
氧化反应代表了在学术界和工业界普遍存在的重要反应。过氧化氢（H2O2）是氧化反应中活性氧的常见来源。H2O2通常在水中稀释，因为它太不稳定而不能以纯净的形式使用。然而，水的存在会使反应复杂化，因为与有机溶剂形成两相混合物。此外，与水的二次反应可能导致副产物。因此，H2O2的替代形式，如过氧化物加合物，是一个活跃的研究领域。氧化膦的二（过氧氢）烷烃加合物是一种有吸引力的溶液，因为它们可溶于有机溶剂，可结晶，贮存稳定并且对各种氧化反应具有活性。唯一的缺点是反应后必须除去氧化膦载体。在该贡献中，双官能配体（EtO）3Si（CH2）2PPh2固定在二氧化硅（SiO2）载体上，其随后用EtOSi（CH3）3封端。然后，以固定化氧化膦为载体，生成新的表面结合的二（过氧氢）丙烷加合物。的加合物和氘代类似物，其特征在于与固态和溶液NMR光谱。它已被证明，在有机溶剂中的基板很容易访问的表面结合的过氧化物和定量氧化。氧化膦载体保持与表面结合，并且可以通过二氧化硅的沉降容易地除去。使用壬醛的氧化酯化，证明了固定化的过氧化物加合物不会从二氧化硅载体中浸出，并且在多个循环中是活性的和可重复使用的。
Oxidations represent important reactions that are ubiquitous in academia and industry. Hydrogen peroxide (H2O2) is a common source of active oxygen for oxidations. H2O2is usually diluted in water as it is too unstable to be used in pure form. However, the presence of water can complicate reactions because biphasic mixtures with organic solvents form. Furthermore, secondary reactions with water may lead to side products. Therefore, alternative forms of H2O2, such as peroxide adducts, are an active area of research. Di(hydroperoxy)alkane adducts of phosphine oxides are one attractive solution because they are soluble in organic solvents, crystallizable, shelf-stable and active towards a variety of oxidation reactions. The only drawback is that the phosphine oxide carrier has to be removed after the reaction. In this contribution, the bifunctional ligand (EtO)3Si(CH2)2PPh2is immobilized on a silica (SiO2) support which is subsequently end-capped with EtOSi(CH3)3. The new surface-bound di(hydroperoxy)propane adduct is then generated with the immobilized phosphine oxide as carrier. The adduct and a deuterated analog are characterized with solid-state and solution NMR spectroscopy. It has been demonstrated that substrates in organic solvents easily access the surface-bound peroxide and are oxidized quantitatively. The phosphine oxide carrier remains bound to the surface and can be removed easily by settling of the silica. Using the oxidative esterification of nonyl aldehyde it is proven that the immobilized peroxide adduct does not leach from the silica support and is active and reusable over multiple cycles.