Efficient Epoxidation of Electron-Deficient Alkenes with Hydrogen Peroxide Catalyzed by [γ-PW10O38V2(μ-OH)2]3−
作者:Keigo Kamata、Kosei Sugahara、Kazuhiro Yonehara、Ryo Ishimoto、Noritaka Mizuno
DOI:10.1002/chem.201101001
日期:2011.6.27
epoxidized without formation of the corresponding amides. In addition, I could rapidly (≤10 min) catalyze epoxidation of various kinds of terminal, internal, and cyclic alkenes with H2O2 under the stoichiometric conditions. The mechanistic, spectroscopic, and kinetic studies showed that the I‐catalyzed epoxidation consists of the following three steps: 1) The reaction of I with H2O2 leads to reversible formation
甲二钒取代的磷钨,[γ-PW 10 ö 38 V 2(μ-OH)2 ] 3-(我),显示出最高的催化活性对H 2 ö 2中钒和钨络合物的乙酸烯丙酯的环氧化的基于营业额为210。在存在I的情况下,烯丙基位置带有乙酸盐,醚,羰基和氯基的各种缺电子烯烃可以高收率将其化学等价地氧化成相应的环氧化物,而等摩尔量的H 2 O 2关于基板。甚至丙烯腈和甲基丙烯腈也可以被环氧化而不形成相应的酰胺。另外,在化学计量比下,我可以快速(≤10分钟)用H 2 O 2催化各种末端,内部和环状烯烃的环氧化。的机理,光谱学,和动力学研究表明,我催化的环氧化反应由以下三个步骤组成:1)的反应我用H 2 ö 2所导致可逆形成一个氢过物种的[γ-PW 10 ö 38 V 2(μ-OH)(μ-OOH)] 3−(II),2)的连续脱水II形式的活性氧种与过氧组[γ-PW 10 ö 38 V 2(μ-η 2:η 2 -O 2)]