离子液体中Mn（Salen）催化仲醇的氧化反应研究

以PhI(OAc)2为氧化剂,考察了1,3-二烷基咪唑硫酸酯系列离子液体中Mn(Salen)催化仲醇氧化的反应. 结果表明, 在MMISM-CH2Cl2(1:4,v:v)混合溶剂中, 反应条件为n((-苯乙醇): n(醋酸碘苯): n(催化剂1c)=50: 70: 1时, (-苯乙醇的转化率可以达到97.8%, 产物苯乙酮的选择性为100%, 远高于在纯CH2Cl2中的结果, 也要好于[bmim]BF4和[bmim]PF6对该反应的促进作用. 此外, BMISM及BEISE对催化剂1c有较好的稳定作用,催化剂可以重复使用.

Oxidation of sec-Alcohols Catalyzed by Mn(Salen) in Ionic Liquids

Oxidation of alcohols to the corresponding carbonyl compounds plays a central role in organic chemistry[1]. Traditionally, the transformation is performed with stoichiometric and toxic oxidants, such as o-iodoxybenzoic acid (IBX), permanganate, chromium reagents, which are cost-ineffective and yield large quantities of noxious waste[2～4]. Therefore, it is not surprising that in the area of oxidative transformations one major goal is the replacement of stoichiometric procedure with catalytic procedures[5～6]. On the other hand, salen as a kind of ligand shows wide applicability and its metal complexes act as highly selective catalysts for a variety of reactions such as epoxidation[7～8], cyclopropanation[9], asymmetric epoxide ring-opening reactions[10], kinetic resolution of sec-alcohols[11] and so on. In our research group, Li Jing-wei employed Mn(Salen) complexes to oxidize sec-alcohols by PhI(Oac)2 in CH3CN with excellent yield in 2004[12].