2026-05-15T16:13:34Zhttps://uvadoc.uva.es/oai/request

oai:uvadoc.uva.es:10324/560042023-10-06T08:04:02Zcom_10324_28542com_10324_952com_10324_894com_10324_1187com_10324_931col_10324_28543col_10324_1408

Squaramide-catalyzed asymmetric Mannich reaction between 1,3-dicarbonyl compounds and pyrazolinone ketimines: A pathway to enantioenriched 4-pyrazolyl- and 4-isoxazolyl-4-aminopyrazolone derivatives Gil Ordóñez, Marta Aubry, Camille Niño, Cristopher Maestro Fernández, Alicia Andrés García, José María A series of N-Boc ketimines derived from pyrazolin-5-ones have been used as electrophiles in enantioselective Mannich reactions with different 1,3-dicarbonyl compounds. This method provides a direct pathway to access the 4-amino-5-pyrazolone derivatives bearing a quaternary substituted stereocenter and containing two privileged structure motifs, the β-diketone and pyrazolinone substructures. The adducts were obtained in excellent yields (up to 90%) and enantioselectivities (up to 94:6 er) by employing a very low loading of 2 mol% of a quinine-derived bifunctional squaramide as an organocatalyst for a wide range of substrates. In addition, the utility of the obtained products was demonstrated through one step transformations to enantioenriched diheterocyclic systems (4-pyrazolyl-pyrazolone and 4-isoxazolyl-pyrazolone), potentially promising candidates for drug discovery. 2022-10-19T08:46:32Z 2022-10-19T08:46:32Z 2022-10-19T08:46:32Z 2022 info:eu-repo/semantics/article Molecules, 2022, vol. 27, n. 20, 6983 1420-3049 https://uvadoc.uva.es/handle/10324/56004 10.3390/molecules27206983 eng https://www.mdpi.com/1420-3049/27/20/6983 info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/4.0/ © 2022 The Authors Atribución 4.0 Internacional MDPI