Heterogeneous Supramolecular Catalysis through Immobilization of Anionic M4L6 Assemblies on Cationic Polymers,Journal of the American Chemical Society

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Heterogeneous Supramolecular Catalysis through Immobilization of Anionic M4L6 Assemblies on Cationic Polymers
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2020-11-02 , DOI: 10.1021/jacs.0c09556
Hiroyuki Miyamura _{1,

2} , Robert G. Bergman ₁ , Kenneth N. Raymond ₁ , F. Dean Toste ₁

Affiliation

Although most of the currently developed supramolecular catalysts that emulate enzymatic reactivity with unique selectivity and activity through specific host-guest interactions work under homogeneous conditions, enzymes in nature can operate under heterogeneous conditions as membrane-bound enzymes. In order to develop such a heterogeneous system, an immobilized chiral supramolecular cluster Ga416 (2) was introduced into cross-linked polymers with cationic functionalities. These heterogeneous supramolecular catalysts were used in aza-Prins and aza-Cope reactions and successfully applied to continuous-flow reactions. They showed high durability and maintained high turnovers for long periods of time. In sharp contrast to the majority of examples of heterogenized homogeneous catalysts, the newly developed catalysts showed enhanced activity and robustness compared to those exhibited by the corresponding soluble cluster catalyst. An enantioenriched cluster was also immobilized to enable asymmetric catalysis, and activity and enantioselectivity of the supported chiral catalyst were maintained during recovery and reuse experiments and under a continuous-flow process. Significantly, the structure of the ammonium cations in the polymers affected stability, reactivity, and enantioselectivity, which is consistent with the hypothesis that the cationic moieties in the polymer support interact with cluster as an exohedral protecting shell, thereby influencing their catalytic performance.

中文翻译：

通过将阴离子 M4L6 组件固定在阳离子聚合物上的多相超分子催化

尽管目前开发的大多数超分子催化剂通过特定的主客体相互作用以独特的选择性和活性模拟酶促反应，但在均相条件下工作，自然界中的酶可以在非均相条件下作为膜结合酶运行。为了开发这种异质系统，将固定的手性超分子簇 Ga416 (2) 引入具有阳离子官能团的交联聚合物中。这些非均相超分子催化剂用于 aza-Prins 和 aza-Cope 反应，并成功应用于连续流动反应。他们表现出很高的耐用性，并在很长一段时间内保持高营业额。与大多数多相均相催化剂的例子形成鲜明对比，与相应的可溶性簇催化剂相比，新开发的催化剂表现出更高的活性和稳定性。还固定了对映体富集的簇以实现不对称催化，并且在回收和再利用实验期间以及在连续流动过程中保持负载型手性催化剂的活性和对映体选择性。值得注意的是，聚合物中铵阳离子的结构影响稳定性、反应性和对映选择性，这与聚合物载体中的阳离子部分与作为外面体保护壳的簇相互作用从而影响其催化性能的假设一致。还固定了对映体富集的簇以实现不对称催化，并且在回收和再利用实验期间以及在连续流动过程中保持负载型手性催化剂的活性和对映体选择性。值得注意的是，聚合物中铵阳离子的结构影响稳定性、反应性和对映选择性，这与聚合物载体中的阳离子部分与作为外面体保护壳的簇相互作用从而影响其催化性能的假设一致。还固定了对映体富集的簇以实现不对称催化，并且在回收和再利用实验期间以及在连续流动过程中保持负载型手性催化剂的活性和对映体选择性。值得注意的是，聚合物中铵阳离子的结构影响稳定性、反应性和对映选择性，这与聚合物载体中的阳离子部分与作为外面体保护壳的簇相互作用从而影响其催化性能的假设一致。

更新日期：2020-11-02

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