Catalytic chemical transformations with conformationally dynamic catalytic systems

Abstract

Proteins, RNA, and other functional biomacromolecules are sophisticated chemical entities that have evolved over billions of years. Their catalytic, constitutional, and communicating functions are intimately related to their three-dimensional molecular architecture and are exquisitely regulated in a spatiotemporal manner by conformational changes through allosteric regulators and a myriad of reversible and unidirectional posttranslational modifications. Their organized functional diversity is the key to the orderly and timely progression of complicated biological events. The main focus in the development of artificial catalysts is to accelerate a specific chemical transformation of interest, and extensive efforts have been devoted to fine-tuning catalytic activity. Here, we review recent developments of multistate catalysts able to perform distinct catalytic functions, with emphasis on the tight link between the structural modification of the conformationally flexible catalysts and the functional change.Although this field is still in its infancy with a simple output, continued advances will allow us to create intriguing systems with organized multitask output in an intricate molecular ensemble. Fig. 1 Focus of reaction-oriented catalysis and function-oriented catalysis.

Supramolecular catalysis. Part 2: artificial enzyme mimics

“…Synthetic allosteric catalysts allow not only for a better understanding of enzymatic processes and the development of catalysts for enzymatic reactions but also for new catalysts for "non-natural" reactions in which the activity/selectivity can be switched by the activator. 376,[626][627][628] Earlier examples described how an intramolecular reaction can be modulated by the addition of well-chosen effectors. 33,[629][630][631][632][633][634] Mirkin and co-workers 376 recently reviewed allosteric catalysts including several examples of allosteric enzyme mimics (NAD(P)H mimic, 631,632 Flavin coenzyme mimics [635][636][637] and several nuclease mimics.…”

“…Synthetic allosteric catalysts not only allow for a better understanding of enzymatic processes and the development of catalysts for enzymatic reactions but also provide access to new catalysts for ''non-natural'' reactions in which the activity/selectivity can be switched by the activator. 376,[626][627][628] Fig. 31 Earlier examples described how an intramolecular reaction can be modulated by the addition of well-chosen effectors.…”

Dynamic control of chirality in phosphine ligands for enantioselective catalysis

“…Responsive catalytic systems in which reactivity or selectivity can be modulated via external non-invasive signals are highly promising to enable tuning of catalytic function, allow spatio-temporal control in chemical transformations and ultimately arrive at multitasking catalysts. In recent years, the development of stimuli- responsive catalysts has attractive considerable attention 1 2 3 and important efforts are related to on–off switching of catalytic activity 4 5 . Remarkable reversal of enantioselectivity in asymmetric catalysis has been achieved using solvent responsive helical polymers 6 , light-triggered organocatalysts 7 8 and redox sensitive metal complexes 9 .…”

Photoswitchable Thioureas for the External Manipulation of Catalytic Activity

“…However, in recent years there has been increasing interest in the development of smart catalytic systems, the function of which can be controlled at will. This can be realized by the use of multistate catalysts , and opens the door to a wide range of potential applications such as controlled drug delivery, mimics of regulatory biocatalysts, or for streamlined multistep syntheses. Different external stimuli have been exploited to induce the change in the state of the catalyst, including acid–base chemistry, mechanical forces, redox processes, and light .…”