0000000001305443
AUTHOR
Marta Guerola
Quatre anys d'experiència educativa en innovació: llicenciatura de Química de la Universitat de València
Articulo de opinion sobre la innovacion educativa en el area de Quimicas. Experiencia en la Universitat de Valencia y dentro de los grupos especificos de innovacion.
ChemInform Abstract: Microwave-Assisted Tandem Organocatalytic Peptide-Coupling Intramolecular aza-Michael Reaction: α,β-Unsaturated N-Acyl Pyrazoles as Michael Acceptors.
Conjugated N-acyl pyrazoles are successfully employed in the organocatalytic enantioselective intramolecular aza-Michael reaction as ester surrogates.
Microwave-Assisted Tandem Organocatalytic Peptide-Coupling Intramolecular aza-Michael Reaction: α,β-UnsaturatedN-Acyl Pyrazoles as Michael Acceptors
Conjugated N-acyl pyrazoles have been successfully employed in the organocatalytic enantioselective intramolecular aza-Michael reaction as ester surrogates. Bifunctional squaramides under microwave irradiation provided the best results in this transformation. Furthermore, this protocol has been combined with a peptide-coupling reaction in a tandem sequence. The final products were easily converted into the corresponding ethyl esters.
Asymmetric Intramolecular Aza-Michael Reaction in Desymmetrization Processes. Total Synthesis of Hippodamine and epi-Hippodamine
The use of chiral sulfinyl amines both as nucleophilic nitrogen sources and chiral inducers has been described for the first time in a desymmetrization-type process involving an intramolecular aza-Michael reaction. The resulting product was employed as an advanced intermediate in the total synthesis of the natural product hippodamine and epi-hippodamine, taking advantage of the special symmetry of these molecules. In addition, this is the first asymmetric total synthesis of epi-hippodamine.
Synthesis of substituted piperidines by enantioselective desymmetrizing intramolecular aza-Michael reactions.
An organocatalytic enantioselective intramolecular aza-Michael reaction has been described for the first time in a desymmetrization process employing substrates different from cyclohexadienones. By using 9-amino-9-deoxy-epi-hydroquinine as the catalyst and trifluoroacetic acid as a co-catalyst, a series of enantiomerically enriched 2,5-and 2,6-disubstituted piperidines have been obtained in good yields and with moderate diastereoselectivity. Depending on the catalyst/co-catalyst loading ratio, either the major or the minor diastereoisomer of the final piperidine products was achieved with high levels of enantioselectivity. Finally, some mechanistic insights have been considered by means of …
ChemInform Abstract: Diastereodivergent Synthesis of Fluorinated Cyclic β3-Amino Acid Derivatives.
The ability of 2-p-tolylbenzyl carbanions to behave as a source of chiral benzylic nucleophiles has been shown in its reaction with fluorinated imines. The process takes place with high levels of stereocontrol, rendering the corresponding amines as single diastereoisomers. Subsequent cross-metathesis followed by intramolecular aza-Michael reaction makes the synthesis of fluorinated homoproline derivatives bearing three stereogenic centers possible. Furthermore, the selectivity of the cyclization process can easily be tuned up in a diastereodivergent manner simply by changing the reaction conditions.
Organocatalytic enantioselective synthesis of 2,5,5-trisubstituted piperidines bearing a quaternary stereocenter. Vinyl sulfonamide as a new amine protecting group
An organocatalytic desymmetrizing intramolecular aza-Michael reaction with vinyl sulfonamides as nucleophilic nitrogen source has been devised for the synthesis of a new family of 2,5,5-trisubstituted piperidines bearing a quaternary sterocenter. The process takes place with excellent levels of enantioselectivity and moderate to good diastereoselectivity. The vinyl sulfonamide moiety can be removed by means of an ozonolysis reaction.
Organocatalytic enantioselective synthesis of quinolizidine alkaloids (+)-myrtine, (-)-lupinine, and (+)-epiepiquinamide
The organocatalytic synthesis of quinolizidine alkaloids (+)-myrtine, (-)-lupinine, and (+)-epiepiquinamide is described. It involved, as the key step, an enantioselective intramolecular aza-Michael reaction (IMAMR) catalyzed by Jorgensen catalyst I, affording the common precursor with high enantioselectivity. This compound was subsequently transformed into the three alkaloids in a highly diastereoselective manner. (C) 2011 Elsevier Ltd. All rights reserved.
Diastereodivergent Synthesis of Fluorinated Cyclic β(3)-Amino Acid Derivatives.
The ability of 2-p-tolylbenzyl carbanions to behave as a source of chiral benzylic nucleophiles has been shown in its reaction with fluorinated imines. The process takes place with high levels of stereocontrol, rendering the corresponding amines as single diastereoisomers. Subsequent cross-metathesis followed by intramolecular aza-Michael reaction makes the synthesis of fluorinated homoproline derivatives bearing three stereogenic centers possible. Furthermore, the selectivity of the cyclization process can easily be tuned up in a diastereodivergent manner simply by changing the reaction conditions.
CCDC 1829500: Experimental Crystal Structure Determination
Related Article: Marta Guerola, Marcos Escolano, Gloria Alzuet-Piña, Enrique Gómez-Bengoa, Carmen Ramírez de Arellano, María Sánchez-Roselló, Carlos del Pozo|2018|Org.Biomol.Chem.|16|4650|doi:10.1039/C8OB01139G
CCDC 1891128: Experimental Crystal Structure Determination
Related Article: Marcos Escolano, Marta Guerola, Javier Torres, Daniel Gaviña, Gloria Alzuet-Piña, María Sánchez-Rosello, Carlos del Pozo|2020|Chem.Commun.|56|1425|doi:10.1039/C9CC09113K