A new strategy for a catalytic C−C bond forming cascade reaction comprising acetal hydrolysis and Knoevenagel condensation is presented here. The heterogeneous nanocatalyst is prepared by immobilizing an ionic liquid on the surface of highly monodisperse silica nanoparticles. This work is the first example of showing that there is no need to use bifunctional acid‐base catalysts for a cascade reaction including the hydrolysis of benzaldehyde dimethyl acetal to benzaldehyde and the subsequent Knoevenagel condensation of the resulting benzaldehyde with malononitrile. It is shown here that these reactions can proceed smoothly with a mono‐functional heterogeneous catalyst that contains a neutral ionic liquid. It has been proposed that such a neutral ionic liquid can “switch on” to an acidic catalyst in conjunction with water. The selected ionic liquid has potentially biodegradability characteristics, which is an important issue to achieve a sustainable catalyst. The simple procedure for preparing both the ionic liquid and the monodisperse silica nanoparticles provides opportunities for a large‐scale synthesis of the catalyst. This work introduces a breakthrough in the design and synthesis of heterogeneous catalysts for acid/base catalyzed cascade organic reactions.

中文翻译：

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用离子液体功能化的二氧化硅纳米颗粒：用于级联反应的绿色高效多相催化剂

本文提出了一种催化 CC 键形成级联反应的新策略，包括缩醛水解和 Knoevenagel 缩合。该多相纳米催化剂是通过将离子液体固定在高度单分散的二氧化硅纳米粒子的表面而制备的。这项工作是第一个例子，表明不需要使用双功能酸碱催化剂进行级联反应，包括苯甲醛二甲缩醛水解为苯甲醛以及随后所得苯甲醛与丙二腈的Knoevenagel缩合。这里表明，这些反应可以使用含有中性离子液体的单功能多相催化剂顺利进行。有人提出，这种中性离子液体可以与水一起“开启”酸性催化剂。所选离子液体具有潜在的生物降解特性，这是实现可持续催化剂的重要问题。制备离子液体和单分散二氧化硅纳米颗粒的简单程序为大规模合成催化剂提供了机会。这项工作在酸/碱催化级联有机反应的多相催化剂的设计和合成方面取得了突破。