Deep eutectic solvents: alternative reaction media for organic oxidation reactions

Carmine, Graziano Di; Abbott, Andrew P.; D’Agostino, Carmine

doi:10.1039/d0re00458h

Cited by 84 publications

(58 citation statements)

References 93 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The catalytic activity of triazolium salts C and D was also tested in selected green solvents to improve the sustainability of the disclosed regiodivergent IS acylation (Table ). − Bio-based polar aprotic solvents were initially screened with the C /DBU couple. Utilization of 2-methyltetrahydrofuran (Me-THF) resulted in long reaction times and moderate exo - selectivity ( 3a / 4a = 59:25, entry 1), while γ-valerolactone (GVL) and dimethyl isosorbide (DMI) completely inhibited the model acylation process (entries 2 and 3).…”

Section: Resultsmentioning

confidence: 99%

Regiodivergent Isosorbide Acylation by Oxidative N-Heterocyclic Carbene Catalysis in Batch and Continuous Flow

Ragno

Leonardi

Carmine

et al. 2021

ACS Sustainable Chem. Eng.

Self Cite

View full text Add to dashboard Cite

A new N-heterocyclic carbene (NHC)-catalyzed strategy for the regioselective monoesterification of isosorbide (IS) at either the endo (5-OH) or exo (2-OH) position is described. Site-selective acylation proceeds under oxidative conditions in the presence of a quinone oxidant using aldehydes as mild acylating agents. Experimental evidences suggest a role of the stereoelectronic features of the acyl azolium salt intermediate in determining the selectivity of the acylation process. The solvent effect was also investigated, considering conventional and sustainable solvents. Aromatic aldehydes, including bio-based furfural and 5-hydroxymethyl furfural, together with α,β-unsaturated aldehydes proved to be effective reaction partners affording monoacyl-isosorbides with satisfactory levels of regioselectivity (exo/endo: 5.3−3.5; endo/exo: 5.3−3.3). Additionally, the exo-selective triazolium salt promoter was successfully transferred into the heterogeneous phase and applied to continuous-flow catalysis. In particular, the polystyrenesupported version of the selected NHC showed a catalytic activity comparable to that of the homogeneous counterpart in terms of both conversion efficiency (turnover number = 108) and regioselectivity (exo/endo up to 5.3). Also, the corresponding packed-bed mesoreactor was operated with long-term stability (ca. 110 h on stream) to produce 2-benzoyl-IS (1.32 mmol h −1 mmol cat −1 ), which is the key intermediate in the synthesis of a commercial active pharmaceutical ingredient, namely, the vasodilator isosorbide-5mononitrate.

show abstract

Section: Resultsmentioning

confidence: 99%

Regiodivergent Isosorbide Acylation by Oxidative N-Heterocyclic Carbene Catalysis in Batch and Continuous Flow

Ragno

Leonardi

Carmine

et al. 2021

ACS Sustainable Chem. Eng.

Self Cite

View full text Add to dashboard Cite

show abstract

“…base was enough for 7 cycles. Because the medium employed (ChCl/Gly) is basic (pH=7.50), [27] it may plausibly be playing an active role in regenerating the base (Scheme 2). Recent studies have also unveiled some critical roles played by base in the Ullmann‐type coupling catalyzed by Cu I in the presence of neutral and bidentate ancillary ligands, like those of assisting other steps of the catalytic cycle, thereby accelerating the cross‐coupling reaction [28] .…”

Section: Resultsmentioning

confidence: 99%

Ligand‐Free Copper‐Catalyzed Ullmann‐Type C−O Bond Formation in Non‐Innocent Deep Eutectic Solvents under Aerobic Conditions

et al. 2021

View full text Add to dashboard Cite

An efficient and novel protocol was developed for a Cucatalyzed Ullmann-type aryl alkyl ether synthesis by reacting various (hetero)aryl halides (Cl, Br, I) with alcohols as active components of environmentally benign choline chloride-based eutectic mixtures. Under optimized conditions, the reaction proceeded under mild conditions (80 °C) in air, in the absence of additional ligands, with a catalyst [Cu I or Cu II species] loading up to 5 mol% and K 2 CO 3 as the base, providing the desired aryloxy derivatives in up to 98 % yield. The potential application of the methodology was demonstrated in the valorization of cheap, easily available, and naturally occurring polyols (e. g., glycerol) for the synthesis of some pharmacologically active aryloxypropanediols (Guaiphenesin, Mephenesin, and Chlorphenesin) on a 2 g scale in 70-96 % yield. Catalyst, base, and deep eutectic solvent could easily and successfully be recycled up to seven times with an E-factor as low as 5.76.

show abstract

“…It must be carefully evaluated before designing a reaction since it can influence the solubility of the reactants and change the activation energy. 100 The solute-solvent interactions of a medium could be recognized by establishing relative polarity scale. But the number of publications based on the polarity of DESs is limited.…”

Section: Surface Tension (C)mentioning

confidence: 99%

Neoteric deep eutectic solvents: history, recent developments, and catalytic applications

Shaibuna

Theresa

2022

Soft Matter

View full text Add to dashboard Cite

show abstract

Deep eutectic solvents: alternative reaction media for organic oxidation reactions

Abstract: Deep Eutectic Solvents (DESs) have emerged an alternative to Ionic Liquids (ILs). DESs share with ILs some appealing features, such as low vapor pressure, capability to dissolve reagents insoluble in...

Cited by 84 publications

References 93 publications

Regiodivergent Isosorbide Acylation by Oxidative N-Heterocyclic Carbene Catalysis in Batch and Continuous Flow

Regiodivergent Isosorbide Acylation by Oxidative N-Heterocyclic Carbene Catalysis in Batch and Continuous Flow

Ligand‐Free Copper‐Catalyzed Ullmann‐Type C−O Bond Formation in Non‐Innocent Deep Eutectic Solvents under Aerobic Conditions

Neoteric deep eutectic solvents: history, recent developments, and catalytic applications

Contact Info

Product

Resources

About