CHAPTER 4. Asymmetric Organocatalytic Reactions under Ball Milling

Machuca, Elizabeth; Juaristi, Eusebio

doi:10.1039/9781782621980-00081

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…Among the advantages offered by mechanochemistry, most important is the complete elimination of solvent, or alternatively the use of very small quantities of it as a grinding assistant (i.e., liquid assisted grinding, LAG) [ 19 ]. From the above, it is evident that mechanochemistry offers a sustainable alternative for the design of clean and efficient processes in the absence of bulk solvent [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

Section: Mechanochemistrymentioning

confidence: 99%

Novel Methodologies for Chemical Activation in Organic Synthesis under Solvent-Free Reaction Conditions

Avila‐Ortiz

Juaristi

2020

Molecules

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One central challenge for XXI century chemists is the development of sustainable processes that do not represent a risk either to humanity or to the environment. In this regard, the search for more efficient and clean alternatives to achieve the chemical activation of molecules involved in chemical transformations has played a prominent role in recent years. The use of microwave or UV-Vis light irradiation, and mechanochemical activation is already widespread in many laboratories. Nevertheless, an additional condition to achieve “green” processes comes from the point of view of so-called atom economy. The removal of solvents from chemical reactions generally leads to cleaner, more efficient and more economical processes. This review presents several illustrative applications of the use of sustainable protocols in the synthesis of organic compounds under solvent-free reaction conditions.

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Section: Mechanochemistrymentioning

confidence: 99%

Novel Methodologies for Chemical Activation in Organic Synthesis under Solvent-Free Reaction Conditions

Avila‐Ortiz

Juaristi

2020

Molecules

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“…Furthermore, removal of the solvent in the reaction leads to a reduction of the generated waste [ 21 , 22 , 23 , 24 , 25 ]. There are several examples in literature of organocatalytic reactions in the absence of solvent [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

Asymmetric Michael Addition Organocatalyzed by α,β-Dipeptides under Solvent-Free Reaction Conditions

Avila‐Ortiz¹,

Díaz-Corona²,

Jiménez-González³

et al. 2017

Molecules

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The application of six novel α,β-dipeptides as chiral organocatalysts in the asymmetric Michael addition reaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMAP) and thiourea as a hydrogen bond donor proved to be highly efficient organocatalytic systems in the enantioselective reaction between isobutyraldehyde and various nitroolefins.

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“…91 Likewise, asymmetric organocatalysis can also take advantage of mechanochemical tools to carry out solvent free (or minimal solvent versions) of existing reactions which proceed via enamine formation among other activation mechanisms. 92 In this regard, it should be noted the pioneering work implemented by Bolm and co-workers, 93 and Nájera and co-workers 94 in aldol and Michael reactions under ball-milling activation.…”

Section: Organocatalysis Via Proline Dipeptide Derivatives Assisted Bmentioning

confidence: 99%

Determination of Enantioselectivities by Means of Chiral Stationary Phase HPLC in Order to Identify Effective Proline-Derived Organocatalysts

Vargas-Caporali¹,

Juaristi²

2017

J. Braz. Chem. Soc.

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The pyrrolidine fragment is a privileged scaffold within chiral ligands employed in coordination complexes exhibiting catalytic activity in asymmetric reactions and, more recently, as enantioselective organocatalysts per se. Likewise, the employment of (S)-proline as starting material constitutes the most direct form to synthesize those chiral derivatives. Afterwards, a preliminary evaluation of the catalytic performance of proline-derived compounds consists of screening many prochiral substrates in well standardized model reactions such as Michael additions and Mannich reactions, with the aim of identifying "broad spectrum" catalysts for more complex synthetic applications. Therefore, a central part of this process involves the fast and direct measurement of enantioselectivities of optically active adducts. The growing development of chiral stationary phases and thus, the wide commercial availability of chiral columns have consolidated high performance liquid chromatography (HPLC) as the preferred technique to identify the most effective catalysts.

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CHAPTER 4. Asymmetric Organocatalytic Reactions under Ball Milling

Cited by 6 publications

References 16 publications

Novel Methodologies for Chemical Activation in Organic Synthesis under Solvent-Free Reaction Conditions

Novel Methodologies for Chemical Activation in Organic Synthesis under Solvent-Free Reaction Conditions

Asymmetric Michael Addition Organocatalyzed by α,β-Dipeptides under Solvent-Free Reaction Conditions

Determination of Enantioselectivities by Means of Chiral Stationary Phase HPLC in Order to Identify Effective Proline-Derived Organocatalysts

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