In this study, we report that selective aerobic oxidation of allyl phenyl ethers is attained by a Pd catalyst/polyoxometalate hybrid system to yield corresponding methyl ketones in water-enriched acetonitrile. The Pd(OAc)₂/H₅PV₂Mo₁₀O₄₀ system exhibits higher conversions and yields of corresponding methyl ketone by Wacker-type oxidation of allyl phenyl ether as compared with the conventional PdCl₂/CuCl₂ system. The higher yields are attributed to the efficient re-oxidation of Pd⁰ to Pd²⁺ by H₅PV₂Mo₁₀O₄₀ using O₂ as an oxidant as evidenced by electrochemical measurements. A reduced species of H₅PV₂Mo₁₀O₄₀ by Pd⁰ during the catalytic oxidation is revealed by UV–vis spectral measurements. The use of PdCl₂ in place of Pd(OAc)₂ in combination with [PV₂Mo₁₀O₄₀]⁵⁻ bearing tetraalkylammonium counter cations has also exhibited comparable conversions and product yields in the Wacker-type oxidation of allyl phenyl ethers. Para-substituted allyl phenyl ether derivatives are successfully oxidized in the Pd catalyst/polyoxometalate system to yield corresponding methyl ketones. The initial rate of products of para-substituted methyl ketones depended on the electronic effect of the substituents in which allyl phenyl ethers with electron-donating groups have accelerated the initial rate in the Pd catalyst/polyoxometalate system.

在这项研究中，我们报告了通过Pd催化剂/多金属氧酸盐杂化体系可实现烯丙基苯醚的选择性好氧氧化，从而在富水乙腈中产生相应的甲基酮。与常规的PdCl ₂ / CuCl ₂系统相比，Pd（OAc）₂ / H ₅ PV ₂ Mo ₁₀ O ₄₀体系表现出更高的转化率和烯丙基苯基醚的Wacker型氧化产生相应的甲基酮。较高的产率归因于H ₅ PV ₂ Mo ₁₀ O ₄₀将Pd ⁰有效地再氧化为Pd ²⁺如电化学测量所证明的，使用O ₂作为氧化剂。紫外可见光谱测量表明，在催化氧化过程中，Pd ⁰减少了H ₅ PV ₂ Mo ₁₀ O ₄₀的种类。与带有[PV ₂ Mo ₁₀ O ₄₀ ] ^5-的四烷基铵抗衡阳离子结合使用PdCl ₂代替Pd（OAc）₂在烯丙基苯基醚的Wacker型氧化中也显示了相当的转化率和产物收率。帕拉取代的烯丙基苯基醚衍生物在Pd催化剂/多金属氧酸盐体系中成功氧化，得到相应的甲基酮。对位取代的甲基酮的产物的初始速率取决于取代基的电子效应，其中具有给电子基团的烯丙基苯基醚已经加速了Pd催化剂/多金属氧酸盐体系中的初始速率。