Evaluating polymer-supported isothiourea catalysis in industrially-preferable solvents for the acylative kinetic resolution of secondary and tertiary heterocyclic alcohols in batch and flow

Guha, Nitul Ranjan; Neyyappadath, Rifahath M.; Greenhalgh, Mark D.; Chisholm, Ross; Smith, S.M.; McEvoy, Megan L.; Young, Claire M.; Rodríguez‐Escrich, Carles; Pericàs, Miquel À.; Hähner, Georg; Smith, Andrew D.

doi:10.1039/c8gc02020e

Cited by 29 publications

(8 citation statements)

References 56 publications

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“…The batch produced material, 5, was purified by conventional Soxhlet extraction for 3 days with the same solvents to mimic the purification process of the flow machine. Functional loading of the polymer resins was quantified according to literature procedures [34,40], by the percentage of nitrogen in CHN elemental analysis and UV-Vis spectroscopic analysis of the filtrate to quantify unreacted 1. 4 were found to have a loading efficiency of 53% (0.33 mmol/ g), significantly higher than 5 produced in batch with only 28% (0.17 mmol/g), demonstrating the greater efficiency of post-synthetic modification in flow through enhanced mass transport.…”

Section: Scheme 1 Synthesis Of Bdp-phoh (1)mentioning

confidence: 99%

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

et al. 2020

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Commercial polystyrene Merrifield-type resins have been post-synthetically functionalised with BODIPY photosensitisers via a novel aryl ester linking strategy in continuous-flow. A unique synthetic advantage of post-synthetically modifying heterogeneous materials in flow was identified. The homogeneous analogues of the polymer-supported BODIPYs were synthesised and used as reference to assess photophysical properties altered by the polymer-support and linker. The homogeneous and polymer-supported BODIPYs were applied in visible-light photosensitisation of singlet oxygen for the conversion of α-terpinene to ascaridole. Materials produced in flow were superior to batch in terms of functional loading and photosensitisation efficiency. Flow photochemical reactions generally outperformed batch by a factor of 4 with respect to rate of reaction. The polymer-supported BODIPY resins could be irradiated for 96 h without loss of photosensitising ability. Additional material synthetic modification and conditions optimisation using an in-line NMR spectrometer resulted in a 24-fold rate enhancement from the initial material and conditions.

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Section: Scheme 1 Synthesis Of Bdp-phoh (1)mentioning

confidence: 99%

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

et al. 2020

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“…Inspired by this apparent limitation in catalyst development in the context of continuous flow operation, we anticipated that a proper immobilization of an appropriate catalyst with substrate activation potential could offer an appealing strategy to design a continuous flow synthesis of cyclic carbonates under mild metal- and halide-free conditions (Scheme b). Among the known cyclic carbonates, glycerol carbonate (GC) stands out as it represents a valuable and versatile bifunctional building block in polymer and small molecule synthesis, and biomedical applications. , Therefore, by merging substrate-assisted CO 2 conversion with organocatalytic flow processes, − we have been able to develop a catalytic process under attractive and stable flow conditions. The results described herein mark a stepping stone toward the sustainable synthesis of a commercially relevant cyclic carbonate product.…”

Section: Introductionmentioning

confidence: 99%

Organocatalytic and Halide-Free Synthesis of Glycerol Carbonate under Continuous Flow

Zanda

Sobolewska

Alza

et al. 2021

ACS Sustainable Chem. Eng.

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Glycerol carbonate is a useful compound of value for a variety of cosmetic, material, and synthetic applications. Its synthesis relies either on the carbonation of glycerol or the conversion of glycidol by reacting it with carbon dioxide under appropriate catalytic conditions. Here, we report the first continuous flow preparation of glycerol carbonate using an immobilized organocatalyst (TBD@Merrifield) that mediates the coupling of glycidol and CO2 under comparative mild reaction and halide-free conditions. Under optimized conditions, glycerol carbonate could be produced throughout a period of 48 h (17.3 g (147 mmol); TON, 99; productivity, 2.04 mmol h–1 mmolcat –1) without any noticeable loss of catalytic performance in this time frame.

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“…Based on the PS‐BTM catalyst, Pericàs and colleagues also developed an immobilized PS‐HyperBTM catalyst, which was successfully applied for the acylative kinetic resolution of a range of secondary and tertiary heterocyclic alcohols in batch and flow conditions. Good to excellent selectivity values were observed …”

Section: Heterogeneous Enantioselective Catalysis In Flowmentioning

confidence: 88%

Recent Advances in Continuous‐Flow Enantioselective Catalysis

Ding

Nie

et al. 2020

Chemistry A European J

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The increased demand for more efficient, safe, and green production in fine chemical and pharmaceutical industry calls for the development of continuous-flowm anufacturing, and for chiral chemicals in particular,e nantioselective catalytic processes. In recenty ears, this emerging direction has received considerable attention and has seen rapid progress. In most cases, catalytic enantioselective flow processes using homogeneous, heterogeneous, or enzymatic catalysts have shown significant advantages over the conventional batch mode,s uch as shortened reaction times, lower catalysts loadings, andh igher selectivities in addition to the normalm erits of non-enantioselective flow operations. In this Minireview,t he advancements, key strategies, methods, and technologiesd eveloped the last six years as well as remaining challenges are summarized.[a] T.

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Evaluating polymer-supported isothiourea catalysis in industrially-preferable solvents for the acylative kinetic resolution of secondary and tertiary heterocyclic alcohols in batch and flow

Abstract: Highly recyclable isothiourea catalysts on various polymer supports are reported for the kinetic resolution of alcohols.

Cited by 29 publications

References 56 publications

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

Organocatalytic and Halide-Free Synthesis of Glycerol Carbonate under Continuous Flow

Recent Advances in Continuous‐Flow Enantioselective Catalysis

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