Crystallization-induced diastereomer transformation assists the diastereoselective synthesis of 4-nitroisoxazolidine scaffolds.

Autor: Esteban A; Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Salamanca. Plaza de los Caídos 1-5, 37008 Salamanca, Spain. ddm@usal.es., Ortega P; Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca. Plaza de los Caídos 1-5, 37008 Salamanca, Spain., Sanz F; Servicio de Difracción de Rayos X, Plataforma Nucleus, Universidad de Salamanca, Plaza de los Caídos 1-5, 37008 Salamanca, Spain., Jambrina PG; Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca. Plaza de los Caídos 1-5, 37008 Salamanca, Spain., Díez D; Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad de Salamanca. Plaza de los Caídos 1-5, 37008 Salamanca, Spain. ddm@usal.es.
Jazyk: angličtina
Zdroj: Organic & biomolecular chemistry [Org Biomol Chem] 2024 Aug 14; Vol. 22 (32), pp. 6582-6592. Date of Electronic Publication: 2024 Aug 14.
DOI: 10.1039/d4ob01014k
Abstrakt: This communication describes a solution to the vexing problem of synthesis of 4-nitroisoxazolidine rings from cyclic nitrones and β-nitrostyrenes. The trans-endo adduct 2 is quantitatively synthesised from E -β-nitrostyrene under mild conditions avoiding purification, while the trans-exo adduct 4 is obtained at higher temperatures. Furthermore, a Crystallization-Induced Diastereomer Transformation (CIDT) process was used to epimerise the NO 2 bond from 2 to the cis-exo adduct 3 with total conversion assisted by the para -halogen substitution of the aromatic ring without any additives. By combining these approaches, we can establish a simple synthetic methodology that allows the diastereoselective synthesis of three diastereoisomers, overcoming the previous problems described in the literature.
Databáze: MEDLINE
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