Thermoregulated phase-transfer catalysis via PEG-armed Ru(II)-bearing microgel core star polymers : Efficient and reusable Ru(II) catalysts for aqueous transfer hydrogenation of ketones
Thermoregulated phase-transfer catalysis via PEG-armed Ru(II)-bearing microgel core star polymers : Efficient and reusable Ru(II) catalysts for aqueous transfer hydrogenation of ketones
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DOI：
10.1002/pola.23794
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发表时间：
2010-01
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影响因子：
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通讯作者：
Takaya Terashima;M. Ouchi;T. Ando;M. Sawamoto
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文献类型：
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作者：
Takaya Terashima;M. Ouchi;T. Ando;M. Sawamoto
通过钌催化活性自由基聚合反应直接制备了具有两亲性、温敏性聚乙二醇（PEG）臂的钌-PEG星星聚合物[Ru（II）-PEG星星]，并将其与苯乙烯衍生物偶联，实现了在2-丙醇/H2O两相介质中对2-辛酮转移氢化反应的温控相转移催化.首先在室温下将星星聚合物置于水层（下部）中，并在100 ℃下立即移动到有机层（上部）中，并在将溶液冷却至室温后再次向下移动到水层（下部）。Ru（II）-PEG星星催化剂在活性和回收/再循环方面明显上级原始Ru（II）催化剂和相关的非微凝胶催化剂[Ru（II）-PEG嵌段]，这是由于微凝胶-核星星聚合物的独特设计结构。其它底物（疏水性较低的烷基酮和芳香酮）也可在水介质中用该星星催化剂有效地加氢生成相应的仲醇。© 2009 Wiley Periodicals，Inc. J Polym Sci Part A：Polym Chem 48：373-379，2010
Thermoregulated phase-transfer catalysis for the transfer hydrogenation of 2-octanone in 2-propanol/H2O biphasic media was achieved with ruthenium-bearing microgel-core star polymers with amphiphilic, thermosensitive poly(ethylene glycol) (PEG) arms [Ru(II)-PEG star], which were directly prepared by the ruthenium-catalyzed living radical polymerization in conjunction with a phosphine ligand-carrying styrene derivative. The star polymers were first placed in the aqueous (lower) layer at room temperature and immediately moved into the organic (upper) layer at 100 °C, and once again, moved down to the aqueous layer (lower) upon cooling the solution to room temperature. The Ru(II)-PEG star catalyst was clearly superior to the original Ru(II) catalyst and related non-microgel catalysts [Ru(II)-PEG block] in terms of activity and recovery/recycle, due to the unique designer structure of the microgel-core star polymers. Other substrates (less hydrophobic alkyl ketones and aromatic ketone) were also efficiently hydrogenated into the corresponding sec-alcohols with the star catalyst in aqueous media. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 373–379, 2010