Novel Enantiopure β-Amino Alcohols and β-Amino Thiols in ...
ligands or by small, chiral, organic molecules (asymmetric organocatalysis). The strategy is advantageous, as it provides not only the benefits of normal catalysis (substoichiometric amounts of
Molecules | Free Full-Text | Ball Milling Promoted N ...
In the last years, numerous protocols have been published using ball milling for organic synthesis. Compared to other methods such as microwave or ultrasound irradiation and ionic liquids, ball mill chemistry is an economical, and ecofriendly method in organic synthesis that is rather underrepresented in the knowledge of organic chemists. The aim of this review is to explore the advantages of ...
Reacciones asimétricas organocatalizadas en ausencia de ...
Efficient ball-mill procedure in the 'green' asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides in the presence of water. Tetrahedron, 67 (2011), pp. …
Organocatalytic solvent-free hydrogen bonding-mediated ...
An efficient, solvent-free protocol for asymmetric Michael additions of α-nitrocyclohexanone to nitroalkenes using thiourea derivatives as hydrogen bonding catalysts has been developed. By performing the organocatalytic reactions in a planetary ball mill, high yields (up to 97%) and excellent enantioselectivities (er up to 98 : 2) were achieved in short reaction times with low catalyst loadings.
Organocatalysis — Organische Chemie
Organocatalysis combines the concepts of molecular recognition as well as supramolecular chemistry with enzyme-like catalytic activity. Noting that about half of all enzymes do not carry a metal center it is obvious that this approach has long been underrated. Although this is a new and emerging field, it is already possible to catalyze many types of organic reactions with small, well-designed ...
Mechanochemistry assisted asymmetric organocatalysis: A ...
Abstract. Ball-milling and pestle and mortar grinding have emerged as powerful methods for the development of environmentally benign chemical transformations. Recently, the use of these mechanochemical techniques in asymmetric organocatalysis has increased. This review highlights the progress in asymmetric organocatalytic reactions assisted by ...
69451 Weinheim, Germany
S2 Detailed procedure for the solvent-free anhydride-opening in the ball mill Preparation of (2R,3S)-3-endo-(4-methyl-benzyloxycarbonyl)-bicyclo[2.2.1]hept-5-ene-2- endo-carboxylic acid (3); A clean, dry ball milling vessel was charged with 60 zirconium oxide grinding balls, the anhydride 1 (1.0 mmol), quinidine (1.1 equiv) and alcohol 2 (1.0 equiv). The vessel was closed, and the milling was ...
Thermal Effects in the Organocatalytic Asymmetric Mannich ...
Solvent-Free Asymmetric Organocatalysis in a Ball Mill. Angewandte Chemie 2006, 118 (41), 7078-7080. DOI: 10.1002/ange.200602820. Belén Rodríguez, Toni Rantanen, Carsten Bolm. Solvent-Free Asymmetric Organocatalysis in a Ball Mill.
Reacciones asimétricas organocatalizadas en ausencia de ...
examples of solvent-free strategies that have converted asymmetric organocatalysis into a more sustainable synthetic methodology. KEYWORDS: Asymmetric organocatalysis, green chemistry, solvent-free reactions, ball-milling Áreas emergentes de la educación Química [Química Verde] 1departamento de Química, centro de investigación y de ...
Asymmetric Synthesis & Catalysis Research Group
The organocatalysis can be merged with photo- and electrocatalysis to develop the synergistic catalytic transformations. We are also doing asymmetric domino/cascade reactions for the stereo-controlled formation of multiple stereogenic centres. We are also interested in organic synthesis through mechano-chemical methods such as ball-milling.
IIT Jammu
Mechanochemical Organic Synthesis, Catalytic Asymmetric Synthesis in Ball-Mill . Shivali Hans. Supervisor Dr Subhas Samanta. Research Area Synthesis and Reactivity of Transition Metal Complexes for Biomimetic Catalysis . ... Asymmetric Photoredox and Organocatalysis . Rahat Gupta. Supervisor Dr Amlan Kumar Pal.
Asymmetric Aldol Reaction Organocatalyzed by (S)-Proline ...
The organocatalytic activity of the methyl ester of (S)-proline-(S)-phenylalanine, (S,S)-2, in the asymmetric aldol reaction between cyclohexanone and acetone with various aromatic aldehydes under solvent-free conditions in a ball mill has been evaluated. α,α-Dipeptide (S,S)-2 catalyzed the stereoselective formation of the expected aldol products, with higher diastereo- and ...
Solvent-Free Asymmetric Organocatalysis in a Ball Mill ...
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Solvent-free asymmetric organocatalysis in a ball mill ...
Solvent-free asymmetric organocatalysis in a ball mill. Rodríguez B, Rantanen T, Bolm C. Author information. Affiliations. All authors. 1. Institut für Organische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52056 Aachen, Germany. ORCIDs linked to this article ...
Solvent‐Free Asymmetric Organocatalysis in a Ball Mill ...
Solvent‐Free Asymmetric Organocatalysis in a Ball Mill Solvent‐Free Asymmetric Organocatalysis in a Ball Mill Rodríguez, Belén; Rantanen, Toni; Bolm, Carsten 00:00:00 Milling around: Aldol and enantioselective anhydride opening reactions were effected in a ball mill under solvent‐free conditions to afford products in high yields and with high enantioselectivities after short ...
Molecules | Free Full-Text | Asymmetric Michael Addition ...
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 ...
Solvent-free asymmetric organocatalysis in a ball mill.
Solvent-free asymmetric organocatalysis in a ball mill. Rodríguez B(1), Rantanen T, Bolm C. Author information: (1)Institut für Organische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen, Landoltweg 1, 52056 Aachen, Germany. PMID: 17001709
Organocatalytic clean synthesis of densely functionalized ...
using the ball milling technique. This procedure is a clean, transition-metal-free, and environmentally friendly approach that offers many advantages including short reaction times, high to quantitative yields, low cost, and straightforward work-up. ARTICLE HISTORY Received 5 April 2015 Accepted 4 January 2016 KEYWORDS Tetraethylammonium 2-
Cite this: RSC Advances 2 REVIEW
ball-milling (HSBM) procedure for direct asymmetric aldol reaction of acetone to isatins (2) using thio-dipeptides as organocatalysts. The thio-peptide 4 catalyzed the formation of 3-acetonyl-3-hydroxy-2-oxindoles (3) in moderate yield (54– 68%) and moderate to good enantioselectivity (56–86% ee) (Scheme 1).
Research | Prof. Dr. Carsten Bolm
Subsequently, the Bolm group extended the research program to organocatalysis, where the initially studied asymmetric desymmetrization of meso-anhydrides was rapidly extended to very many other catalytic applications of purely organic molecules. In 2014, Bolm was the first to perform asymmetric organocatalysis in a ball mill, and this ...
Solvent-free asymmetric aldol reaction organocatalyzed …
An efficient, solvent-free ball-milling protocol for the asymmetric aldol reaction between cyclohexanone and cyclopentanone with various aromatic aldehydes using a novel series of (S)-proline-containing dipeptides and thiodipeptides 1a–f as organocatalysts is reported.In general, (S)-proline-containing thiodipeptides proved to be better organocatalysts relative to their analogous amides.
Asymmetric Organocatalytic Reactions under Ball Milling ...
In particular, after in situ formation of the ligand by ball milling, metal salts (ZnO, Ni (OAc)2·4H2O or Cu (OAc)2·H2O) were added directly to the jar and milling continued for a further 30 ...
Asymmetric organocatalysis in a ball mill - TIB AV-Portal
In this video the authors present asymmetric organocatalyses performed in a ball mill. Three reaction types are being discussed: enantioselective aldol reactions, asymmetric Michael additions to nitro alkenes and dipeptide formations. In the laboratory the ball milling device is shown, and reaction details are revealed. Finally, future applications of mechanochemical biomass degradations are ...
(PDF) Solvent-free asymmetric aldol reaction ...
Furthermore, the enantiomeric excesses in aldol product 6a were ndez et al. / Tetrahedron 68 (2012) 92e97 J.G. Herna 95 MeO O Table 3 S Scope of the direct asymmetric aldol reaction of cyclic ketones with various alde- N hydes catalyzed by (S,S)-1d under ball-milling conditionsa H O O O OH N O NO2 7 mol% (S,S)-1d +H R R + syn isomer Ball ...
Organocatalysis - THE SEBESTA GROUP
The Michael adducts were obtained in good yields, diastereomeric purities up to 94:6 and enantiomeric purities up to 2:98. Michael additions proceeded well also under solvent-free ball-milling conditions. These adducts were reductively cyclized to the corresponding chiral 3,4-disubstituted pyrrolidines.
Optimization of Milling Procedures for Synthesizing Nano ...
Ball mill is a high-energy mill process especially used for an energy-intensive process like mechanical alloying, mechanochemistry, or mechanical activation. Planetary ball mill is used to determine the dependence of process efficiency using milling parameters such as ball size and number, mill geometry, and velocity of the rotating parts.
Solvent‐Free Asymmetric Organocatalysis in a Ball Mill ...
Solvent‐Free Asymmetric Organocatalysis in a Ball Mill † Belén Rodríguez Dr. Institut für Organische Chemie, Rheinisch‐Westfälische Technische Hochschule Aachen, Landoltweg 1, 52056 Aachen, Germany, Fax: (+49) 241‐809‐2391
Green asymmetric organocatalysis - Beilstein-Institut
Green asymmetric organocatalysis Radovan Šebesta / Comenius University in Bratislava March 11, 2021, 2 - 3 pm CET Online live talk. Introduction. ... and hydrazination of aldehydes can be performed in aqueous media or under solventless conditions using a ball mill. We have found out that these reactions proceed with high yields and highly ...
Solvent-Free Asymmetric Organocatalysis in a Ball Mill ...
Request PDF | Solvent-Free Asymmetric Organocatalysis in a Ball Mill | (Chemical Equation Presented) Milling around: Aldol and enantioselective anhydride opening …
Publications | The Morrill Research Group
"Ball Milling Enabled Reactivity of Manganese Metal", W. I. Nicholson, J. L. Howard, ... [Invited contribution to the Hybrid Catalysts for Asymmetric Catalysis Special Issue] ... "N-Heterocyclic Carbene Acyl Anion Organocatalysis by Ball-Milling", W. I. Nicholson, A. C. Seastram, ...