Title:Diastereoselective Synthesis of Nitropyrrolizidines from Enantiopure exo- 4-Nitro-3,5-diphenylproline through 1,3-Dipolar Cycloadditions of non- Stabilized Azomethine Ylides
VOLUME: 15 ISSUE: 5
Author(s):Eduardo Garcia-Minguens, Carmen Najera* and Jose M. Sansano*
Affiliation:Departamento de Quimica Organica and Centro de Innovacion en Quimica Avanzada (ORFEO-CINQA), Facultad de Ciencias, Universidad de Alicante, 03080-Alicante, Departamento de Quimica Organica and Centro de Innovacion en Quimica Avanzada (ORFEO-CINQA), Facultad de Ciencias, Universidad de Alicante, 03080-Alicante, Departamento de Quimica Organica and Centro de Innovacion en Quimica Avanzada (ORFEO-CINQA), Facultad de Ciencias, Universidad de Alicante, 03080-Alicante
Keywords:Pyrrolizidine, nitroprolinates, cycloaddition, azomethine ylides, decarboxylation, multicomponent.
Abstract:Enantiopure exo-4-nitro-3,5-diphenylproline reacts with aldehydes and electrophilic alkenes,
in good yields, through a multicomponent 1,3-dipolar cycloaddition where the intermediate azomethine
ylide is generated by the decarboxylative route. The reactions with maleimides afford diastereoselectively
nitropyrrolizidines. Dimethyl fumarate and 1,2-bis(phenylsulfonyl)ethylene also give variable
mixtures of diastereoisomeric nitropyrrolizidines. The replacement of aldehydes by phenyl-3-buten-2-
one also affords satisfactory results with high diastereoselection although in lower yields. The stereochemical
outcome is studied and defined according to the absolute configuration of the resulting cycloadducts.
