Tuneable Control of Organocatalytic Activity through Host–Guest Chemistry. Issue 25 (7th May 2021)

• Record Type: Journal Article
• Authors: Li, Guotai; Trausel, Fanny; van der Helm, Michelle P.; Klemm, Benjamin; Brevé, Tobias G.; van Rossum, Susan A. P.; Hartono, Muhamad; Gerlings, Harm H. P. J.; Lovrak, Matija; van Esch, Jan H.; Eelkema, Rienk
• Is Part Of: Angewandte Chemie international edition. Volume 60:Issue 25(2021)
• Page Start: 14022
• Page End: 14029
• Publication Date: 2021-05-07
• Subjects: cucurbit[7]uril -- host–guest systems -- organocatalysis -- responsive systems -- supramolecular chemistry; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.202102227
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Dynamic regulation of chemical reactivity is important in many complex chemical reaction networks, such as cascade reactions and signal transduction processes. Signal responsive catalysts could play a crucial role in regulating these reaction pathways. Recently, supramolecular encapsulation was reported to regulate the activities of artificial catalysts. We present a host‐guest chemistry strategy to modulate the activity of commercially available synthetic organocatalysts. The molecular container cucurbit[7]uril was successfully applied to change the activity of four different organocatalysts and one initiator, enabling up‐ or down‐regulation of the reaction rates of four different classes of chemical reactions. In most cases CB[7] encapsulation results in catalyst inhibition, however in one case catalyst activation by binding to CB[7] was observed. The mechanism behind this unexpected behavior was explored by NMR binding studies and p K a measurements. The catalytic activity can be instantaneously switched during operation, by addition of either supramolecular host or competitive binding molecules, and the reaction rate can be predicted with a kinetic model. Overall, this signal responsive system proves a promising tool to control catalytic activity. Abstract : Binding an organocatalyst inside a cucurbituril molecular host can reversibly up‐ or downregulate catalytic activity, which is demonstrated in temporal control over the rate of a range of organocatalyzed transformations.