title: Multicomponent synthesis of unnatural pyrrolizidines using 1,3-dipolar cycloaddition of proline esters.
abstract: The synthesis of unnatural pyrrolizidines has been studied using a multicomponent-domino process involving proline or 4-hydroxyproline esters, an aldehyde and a dipolarophile. The formation of the iminium salt promotes the 1,3-dipolar cycloaddition affording highly substituted pyrrolizidines under mild conditions and high regio- and diastereoselectivities.
authors.affiliation: Departamento de Química Orgánica e Instituto de Síntesis Orgánica, Universidad de Alicante, E-03080-Alicante, Spain. cnajera@ua.es jmsansano@ua.es.
authors.forename: Juan
authors.initials: J
authors.lastname: Mancebo-Aracil
authors.forename: Carmen
authors.initials: C
authors.lastname: Nájera
authors.forename: José M
authors.initials: JM
authors.lastname: Sansano
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D061565:Cycloaddition Reaction; D004952:Esters; D011392:Proline / Q000737:chemistry*; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D004952:Esters; D011763:Pyrrolizidine Alkaloids; D011392:Proline