Compartmentalization of Incompatible Reagents within Pickering Emulsion Droplets for One-Pot Cascade Reactions

Yang, Hengquan; Fu, Luman; Wei, Lijuan; Liang, Jifen; Binks, Bernard P.

doi:10.1021/ja512337z

Cited by 221 publications

(192 citation statements)

References 56 publications

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“…Novel concepts and ideas for immobilization, such as the use of metal-organic frameworks 107 , compartmentalization by 'Pickering emulsion' droplets 108 , mimicking biological membranes 109 or protein containers 110 , may pave the road towards more suitable and industrially applicable concurrent chemoenzymatic tandem reactions.…”

Section: Future Challengesmentioning

confidence: 99%

Opportunities and challenges for combining chemo- and biocatalysis

et al. 2018

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N ature has evolved highly efficient systems in the form of cascade reactions, which assemble the metabolic networks that support life (growth and survival). The basic principle of cascade reactions is also frequently used in biocatalysis, using enzymes in isolation, as well as in combination with chemocatalysts (see Fig. 1 and Box 1 for definition of terms) [1][2][3][4][5][6][7] . As there is no need for purification and isolation of intermediates, operating time, production costs and waste are reduced, and concomitantly, overall yields are improved. In addition, the problem of unstable or difficult to handle intermediates can be overcome, and reactivity as well as selectivity can be enhanced by avoiding unfavourable reaction equilibria through the cooperative effects of multiple catalysts 8 . Starting in the 1980s, the early examples of the combination of chemo-and biocatalysts were reported by the van Bekkum group, who pioneered the development of a process to make the sugar substitute d-mannitol from readily available d-glucose through the combination of a heterogeneous metal-catalysed hydrogenation and an enzyme-catalysed isomerization 9 . The first broadly applied technology for the combination of enzyme and metalcatalysts, which was the research subject of many academic groups as well as industry, emerged in the 1990s from the Williams group 10,11 and aimed to achieve higher yields than classical kinetic resolution of racemates, thus overcoming the limitation of a maximum yield of 50% in the latter case. A prominent example of work that developed this theme is the combination of lipase-catalysed kinetic resolution via acylation of secondary alcohols with Pd-or Rh-catalysed racemization via reversible transfer hydrogenation to achieve a dynamic kinetic resolution (DKR) [12][13][14] . This example was facilitated in part because lipases are active and stable in organic solvents. Later, for instance, Turner's group combined a monoamine oxidase-catalysed imine formation with a chemical reduction 15 to achieve the 100% theoretical yield through a deracemization process. In addition to the combination of metalcatalysis with enzymes, organocatalysis, electrochemistry and light-induced reaction couples have since then been studied extensively, going far beyond the scope of a DKR.The challenges to combining chemo-and biocatalysis in cascades (see Box 1 for definitions and Table 1) can be daunting, not least the requirement for the chemical step to occur in the presence of water, the preferred solvent for enzymes 3 . This Review therefore highlights recent examples of the combination of chemo-and biocatalysts in aqueous multistep syntheses, and looks at how to overcome limitations by, for example, design of appropriate reaction conditions, protein engineering and advanced reactor concepts. Furthermore, trends such as the integration of transition metalcatalysis into microorganisms and the introduction of novel chemistry into engineered enzymes are discussed, and a critical assessment of the impact of this research ...

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Section: Future Challengesmentioning

confidence: 99%

Opportunities and challenges for combining chemo- and biocatalysis

et al. 2018

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“…Stirring (900 rpm) could dramatically improve the CE up to 0.5 mol mol À1 h À1 (Figure 3B,b )o wing to the enhanced mass transport. [28][29][30][31] The large reaction interface area and short molecule diffusion distance createdb yt he Pickering emulsion account for the high reaction efficiency without need for stirring. If the conventional biphasic system was changed to aP icking emulsion system, the cyclization reaction proceeded faster,a nd the conversion reacheda bove 80 %a fter 10 ha nd above 93 %a fter 15 h ( Figure 3A,c ), much highert han those of the conventionalb iphasic systems.…”

Section: Resultsmentioning

confidence: 99%

Flow Pickering Emulsion Interfaces Enhance Catalysis Efficiency and Selectivity for Cyclization of Citronellal

Chen

Hao

et al. 2017

ChemSusChem

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Cyclization of citronellal is a necessary intermediate step to produce the important flavor chemical (-)-menthol. Here, a continuous-flow Pickering emulsion (FPE) strategy for selective cyclization of citronellal to (-)-isopulegol by using water droplets hosting a heteropolyacid (HPA) catalyst to fill a column reactor is demonstrated. Owing to the large liquid-liquid interface and the excellent confinement ability of droplets toward HPA, the FPE system exhibited a much higher catalysis efficiency than its batch counterpart (2-5-fold) and an excellent durability (two months). Moreover, a remarkably enhanced selectivity was observed from 34.8 % for batch reactions to 64 % for the FPE reactions. It was found that the water droplet size and the flow rate significantly impact the catalysis selectivity and efficiency. This study not only represents an unprecedented and sustainable process for the selective cyclization of citronellal but also demonstrates a new flow-interface catalysis effect that can be useful for designing innovative catalysis systems in the future.

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“…A recognition that multicompartmentalization provides spatiotemporal control over reactions, high local reactant concentrations, concentration gradients, and the separation of incompatible reaction components has motivated developments in novel microreactor architectures. [25] These structures are often based on a liposome-in-liposome design or built using liposomes contained within layer-by-layer (LbL) capsules. For example, the Möhwald and Sukhorukov groups have jointly reported a concentric, two-compartment, LbL capsule-in-capsule architecture based on polyelectrolyte systems (Figure 5).…”

Section: Recent Advances In Synthetic Cell Membranesmentioning

confidence: 99%

Towards Self‐Assembled Hybrid Artificial Cells: Novel Bottom‐Up Approaches to Functional Synthetic Membranes

Brea

Hardy

Devaraj

2015

Chemistry A European J

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There has been increasing interest in utilizing bottom-up approaches to develop synthetic cells. A popular methodology is the integration of functionalized synthetic membranes with biological systems, producing “hybrid” artificial cells. This Concept article covers recent advances and the current state-of-the-art of such hybrid systems. Specifically, we describe minimal supramolecular constructs that faithfully mimic the structure and/or function of living cells, often by controlling the assembly of highly ordered membrane architectures with defined functionality. These studies give us a deeper understanding of the nature of living systems, bring new insights into the origin of cellular life, and provide novel synthetic chassis for advancing synthetic biology.

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Compartmentalization of Incompatible Reagents within Pickering Emulsion Droplets for One-Pot Cascade Reactions

Cited by 221 publications

References 56 publications

Opportunities and challenges for combining chemo- and biocatalysis

Opportunities and challenges for combining chemo- and biocatalysis

Flow Pickering Emulsion Interfaces Enhance Catalysis Efficiency and Selectivity for Cyclization of Citronellal

Towards Self‐Assembled Hybrid Artificial Cells: Novel Bottom‐Up Approaches to Functional Synthetic Membranes

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