Buscar
Mostrando ítems 1-9 de 9
Artículo
Preparation of Chitosan-supported Urea Materials and their Application in Some Organocatalytic Procedures
(Elsevier, 2018)
An efficient and mild procedure was developed for the preparation of three chitosan-supported ureas containing electron-withdrawing groups. These catalysts were characterized and employed as organocatalysts in different ...
Artículo
Bifunctional Squaramide Organocatalysts for the Asymmetric Addition of Formaldehyde tert-Butylhydrazone to Simple Aldehydes
(Wiley-Blackwell, 2018)
The nucleophilic addition of formaldehyde tert-butylhydrazone to simple aldehydes (a formal hetero-carbonyl–ene reaction) can be performed with good reactivity and excellent enantioselectivity by virtue of the dual ...
Artículo
Total asymmetric synthesis of monosaccharides and analogues
(Schweizerische Chemische Gesellschaft (Swiss Chemistry Society), 2011)
Since the discovery of the 'formose reaction' by Butlerow,[1] total synthesis of carbohydrates has undergone rapid development. The most important methods for the asymmetric synthesis of monosaccharides and analogues of ...
Artículo
Stereoselective Synthesis of Iminosugar 2-Deoxy(thio)glycosides from Bicyclic Iminoglycal Carbamates Promoted by Cerium(IV) Ammonium Nitrate and Cooperative Brønsted Acid-Type Organocatalysis
(American Chemical Society, 2020)
The first examples of iminosugar-type 2-deoxy(thio)glycoside mimetics are reported. The key step is the activation of a bicyclic iminoglycal carbamate to generate a highly reactive acyliminium cation. Cerium(IV) ammonium ...
Artículo
Enantio- and Diastereoselective Nucleophilic Addition of N-tert-Butylhydrazones to Isoquinolinium Ions through Anion-Binding Catalysis
(Wiley-Blackwell, 2021)
A highly enantio- and diastereoselective thiourea-catalyzed dearomatization of isoquinolines employing N-tert-butylhydrazones as neutral α-azo carbanions and masked acyl anion equivalents has been developed. Experimental ...
Artículo
Recent developments in the synthesis of β-diketones
(Multidisciplinary Digital Publishing Institute (MDPI), 2021)
Apart from being one of the most important intermediates in chemical synthesis, broadly used in the formation of C–C bonds among other processes, the β-dicarbonyl structure is present in a huge number of biologically and ...
Artículo
Deracemisation Processes Employing Organocatalysis and Enzyme Catalysis
(Wiley-Blackwell, 2020)
Deracemisation methods have demonstrated their importance in the preparation of chiral compounds in the last few years. In order to resolve a racemic mixture in a dynamic sense, one enantiomer of the starting material can ...
Artículo
Application of Biobased Solvents in Asymmetric Catalysis
(Multidisciplinary Digital Publishing Institute (MDPI), 2022)
The necessity of more sustainable conditions that follow the twelve principles of Green Chemistry have pushed researchers to the development of novel reagents, catalysts and solvents for greener asymmetric methodologies. ...
Artículo
Iminosugar-Phosphines as Organocatalysts in the [3 + 2] Cycloaddition of Allenoates and N-Tosylimines
(Multidisciplinary Digital Publishing Institute (MDPI), 2022)
Iminosugar derivatives containing a pyrrolidine-phosphine moiety were prepared from carbohydrates and used as catalysts in the [3 + 2] cycloaddition reaction between alkyl allenoates and electron-deficient imines. The ...