PEG as an alternative reaction medium in metal-mediated transformations

Colacino, Evelina; Martinez, Jean; Lamaty, Frédéric; Patrikeeva, Lyudmila S.; Khemchyan, Levon L.; Ananikov, Valentine P.; Beletskaya, I. P.

doi:10.1016/j.ccr.2012.05.027

Cited by 95 publications

(44 citation statements)

References 112 publications

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“…Between runs the catalyst was dried at 60°C or calcined at 550°C and weighed before the next run, in order to maintain a constant substrate-to-catalyst ratio. 43 The FTIR spectra of the as-synthesized SnP-PEG2000 confirm that the catalyst was stable after three consecutive runs (Fig. 9.…”

Section: Catalyst Recyclabilitymentioning

confidence: 72%

Highly active tin(iv) phosphate phase transfer catalysts for the production of lactic acid from triose sugars

Wang

Liang

Huang

et al. 2015

Catal. Sci. Technol.

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Lactic acid (LA) is an important intermediate in the fine chemical industry because it is utilized as a building block for the production of biodegradable plastics. In this study, a series of tin phosphate phase transfer catalysts modified with several surfactants have been prepared by a facile one-pot synthesis method and tested for the direct conversion of trioses to LA under hydrothermal conditions. Poly(ethylene glycol) (PEG) was identified as the most promising surfactant, and the product distribution closely depended on the reaction temperature, catalyst loading and substrate concentration. Complete DHA conversion and a good yield of up to 96.1% of LA were obtained at 140°C after 4 h of reaction time. Pyridine FTIR demonstrated the presence of Brønsted and Lewis acid sites, which play crucial roles in the dehydration of DHA to pyruvaldehyde (PA) and the following isomerization of generated PA to LA. Furthermore, the isomerization of PA to LA was found to be the rate-determining step. A possible reaction mechanism was proposed: 1) the coordination between PEG and the metal ions caused a greater separation of the tin ions from the phosphate anions, making them more potent Lewis acid sites, and 2) the PEG behaved as a phase transfer catalyst during the reaction. This study paves the way for the further design of improved solid acid catalysts for aqueous phase production of LA from carbohydrates.Catal. Sci. Technol. This journal is † Electronic supplementary information (ESI) available: Catalytic conversion of GLA to LA by SnP with various surfactants, the results of DHA after a prolonged reaction time of 6 h and the postulated roles of SnP-PEG2000. See

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Section: Catalyst Recyclabilitymentioning

confidence: 72%

Highly active tin(iv) phosphate phase transfer catalysts for the production of lactic acid from triose sugars

Wang

Liang

Huang

et al. 2015

Catal. Sci. Technol.

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“…Poly(ethylene) glycols (PEGs) are eco-friendly solvents [1–2], finding applications in the biomedical field and for pharmaceutical formulations [3] and catalysis [4]. PEG-based reaction media [1] are safe reaction environments, efficiently heated by microwaves [5], but their use in organic transformations activated by other alternative energy inputs is still scarce.…”

Section: Introductionmentioning

confidence: 99%

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

Mascitti¹,

Lupacchini²,

Guerra³

et al. 2017

Beilstein J. Org. Chem.

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The mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins was investigated in the presence of various poly(ethylene) glycols (PEGs), as safe grinding assisting agents (liquid-assisted grinding, LAG). A comparative study under dry-grinding conditions was also performed. The results showed that the cyclization reaction was influenced by the amount of the PEG grinding agents. In general, cleaner reaction profiles were observed in the presence of PEGs, compared to dry-grinding procedures.

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“…The starting point of both cycles is a Pd(0) species, suggesting that when a palladium(II) precatalyst is used, its reduction should occur first, as the oxidative addition of an aryl halide to a Pd(II) compound is not favored. Various palladium(II) reduction pathways using an excess of phosphine ligand [67] (oxidized to phosphine oxide) or alcohols (oxidized to aldehydes) [30] have been reported [22,68,69,70].…”

Section: Mechanismmentioning

confidence: 99%

Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals

Loxq

Manoury

Poli

et al. 2016

Coordination Chemistry Reviews

290

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Please cite this article as: P. Loxq, E. Manoury, R. Poli, E. Deydier, A. Labande, Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals, Coordination Chemistry Reviews (2015), http://dx. AbstractAxially chiral biaryl structures are unique systems encountered in various synthetic compounds such as BINAP and BINOL, polymers, but also in natural products presenting a pharmaceutical interest such as Vancomycin, Steganacin or Korupensamine. The axial chirality of these products, so-called atropisomerism, is induced by the restricted rotation around the aryl-aryl bond. This review will summarize the different strategies imagined by chemists to control such chirality, focusing on asymmetric catalytic processes with transition metals. Only transition metal complexes bearing chiral ligands will be considered and the core of this review will consist of the enantioselective coupling of two achiral substrates. Highlights 1. A review on the synthesis of axially chiral biaryls by asymmetric catalysis 2. Exhaustive description of chiral ligands used in the palladium-catalyzed SuzukiMiyaura cross-coupling reaction 3. Emerging reactions such as asymmetric direct C-H functionalization are presented 4. Asymmetric [2+2+2] cycloadditions catalyzed by group 9 transition metals are included

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PEG as an alternative reaction medium in metal-mediated transformations

Cited by 95 publications

References 112 publications

Highly active tin(iv) phosphate phase transfer catalysts for the production of lactic acid from triose sugars

Highly active tin(iv) phosphate phase transfer catalysts for the production of lactic acid from triose sugars

Poly(ethylene glycol)s as grinding additives in the mechanochemical preparation of highly functionalized 3,5-disubstituted hydantoins

Synthesis of axially chiral biaryl compounds by asymmetric catalytic reactions with transition metals

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