Carbon nanotubes help nickel work in water Most synthetic chemistry takes place in hydrocarbon-derived solvents. By contrast, enzymes manage to perform exquisitely selective reactions in water, often by surrounding reactants with hydrophobic pockets. Kitanosono et al. show that single-walled carbon nanotubes can similarly render simple nickel catalysts effective in water. Integration of the nickel ions with chiral ligands and surfactants at the nanotube surface produces a highly enantioselective catalyst for nitrone formation from aldoximes and unsaturated ketones. Spectroscopy suggests that the nanotubes enhance electron density at the nickel center as well as provide a hydrophobic milieu. Science, this issue p. 311 A combination of surfactants and supporting single-walled carbon nanotubes render chiral nickel catalysts effective in water. The development of highly reactive and stereoselective catalytic systems is required not only to improve existing synthetic methods but also to invent distinct chemical reactions. Herein, a homogenized combination of nickel-based Lewis acid–surfactant-combined catalysts and single-walled carbon nanotubes is shown to exhibit substantial activity in water. In addition to the enhanced reactivity, stereoselective performance and long-term stability were demonstrated in asymmetric conjugate addition reactions of aldoximes to furnish chiral nitrones in high yields with excellent selectivities. The practical and straightforward application of the designed catalysts in water provides an expedient, environmentally benign, and highly efficient pathway to access optically active compounds.

中文翻译：

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手性路易斯酸与单壁碳纳米管集成在水中的不对称催化

碳纳米管帮助镍在水中发挥作用 大多数合成化学发生在碳氢化合物衍生的溶剂中。相比之下，酶设法在水中进行精细的选择性反应，通常是通过用疏水袋包围反应物。Kitanosono 等。表明单壁碳纳米管可以类似地使简单的镍催化剂在水中有效。镍离子与纳米管表面的手性配体和表面活性剂的整合产生了一种高度对映选择性的催化剂，用于从醛肟和不饱和酮形成硝酮。光谱学表明，纳米管提高了镍中心的电子密度并提供了疏水环境。科学，这个问题 p。311 表面活性剂和支撑单壁碳纳米管的组合使手性镍催化剂在水中有效。开发高反应性和立体选择性催化系统不仅需要改进现有的合成方法，还需要发明不同的化学反应。在此，镍基路易斯酸-表面活性剂组合催化剂和单壁碳纳米管的均质组合在水中表现出显着的活性。除了增强的反应性外，立体选择性性能和长期稳定性在醛肟的不对称共轭加成反应中得到证明，以高产率和优异的选择性提供手性硝酮。设计的催化剂在水中的实际和直接应用提供了一种方便、环境友好且高效的获取光学活性化合物的途径。