Stimuli-responsive Cooperative Catalysts Based on Dynamic Conformational Changes toward Spatiotemporal Control of Chemical Reactions

Abstract

Stimuli-responsive cooperative catalysts that reversibly switch the catalytic function on the basis of the dynamic conformational changes induced by external stimuli have been incrementally developed in recent years.

Dynamic Responsive Systems for Catalytic Function

“…Making artificial responsive catalysts that can mimic the allosteric regulation of enzymes presents a major challenge. In recent years there has been increased interest in making stimuli‐responsive dynamic catalysts that can switch their catalytic activity or selectivity . Upon exposure to external stimuli, catalysts undergo conformational changes, which can result in a change of their catalytic function (Scheme ).…”

Cofactor Controlled Encapsulation of a Rhodium Hydroformylation Catalyst

“…Chemists are at the beginning of building synthetic catalysts with similar functions, with the long‐term aim to control chemical pathways in more complex chemical mixtures . In this context, there is increasing interest in synthetic catalysts that can be switched by external stimuli or cofactors . Most of these studies have been carried out using relatively simple hydrolysis reactions and organocatalytic reactions, and the number of transition‐metal catalysts that have a switching function is very limited .…”

Bifunctional Molecular Photoswitches Based on Overcrowded Alkenes for Dynamic Control of Catalytic Activity in Michael Addition Reactions

“…Notably, these two pairs of catalytic functional groups would also be addressed with two opposite helical chirality, P or M , upon irradiation and thermal relaxation. We envisioned such a design as a feasible future route for stimuli‐responsive switchable catalysts in multi‐tasking systems and one‐pot multi‐step diastereo‐ and enantioselective reactions …”

“…External control of catalytic systemsb yl ight is ah ighly challenging and still underdeveloped field of moderno rganic chemistry.I nt he quest for responsive catalytic systems, many advantages arise from the use of light as ac lean, non-invasive stimulus,i nw hich judicious choiceo fi rradiation wavelength may allow precise control over catalyst function, activity and selectivity.Anumber of photoresponsive catalysts have been developed over the last decade, exploiting the established switching properties of azobenzenes,d iarylethenesa nd overcrowded alkenes. [1][2][3][4][5] Promising resultsi np hotochemical control of catalyst activity or selectivity have been achieved through different approaches by harnessing cooperative, [6][7][8][9][10][11][12] steric [13][14][15][16][17][18][19][20] and electronic effects [21][22][23][24][25] of the photo-accessible isomers.…”

“…[26] Successfula pplication was found in the enantiodivergent Steglich rearrangement of O-t oC-carboxylazlactones, with formation of either enantiomer with up to 91 (R)a nd 94 % ee (S), respectively.B randaa nd co-workersd eveloped variouss ystemsf or exploiting the characteristic switching of structural and electronic properties of diarylethenes to allow,f or instance, the control of Lewis acidity/ basicity, [27,28] stereoselectivity [8] and substrate reactivity, [29][30][31][32][33] Other approaches, includingt he application of photoresponsive systems for controlling the rate of ring-opening polymerizations, [24,[34][35][36] are summarized in recent comprehensive reviews. [1][2][3][4][5] Our group has demonstrated stimuli-responsive control of the activity and enantioselectivity of ac atalyst by dynamic conformational changes of af irst generation molecular motor equipped with two functional groups able to cooperatively accelerate ar eaction( Scheme 1b;f or the switching process of the main core, see Scheme 2a). [9] The two pseudo-enantiomeric (Z)-isomers of the molecular motor during its rotary cycle were shown to control the stereochemical outcome of an organocatalytic thiol 1,4-addition, allowing accesst ob oth enantiomerso ft he product depending on the state of the catalyst.…”