Studies towards the Construction of Quaternary Indolizidines by [2,3]-Sigmatropic Rearrangement Cocatalyzed by Ionic Liquid

Duran-Lara, EF; Shankaraiah, N.; Geraldo, D; Santos, LS

Abstract

An efficient enantioselective approach for preparation of quaternary centers from proline 5 building block has been developed through [2,3]-sigmatropic Stevens rearrangement co-catalyzed by ionic liquid. The sigmatropic rearrangement was stereospecific because the [2,3]-migrations were restricted to the same face, and the stereoselectivity arose from the previous N-alkylation step in 8. The approach showed better yields than described in literature. The use of 1-butyl-3-methylimidazolium hexafluorophosphate showed an improvement in the yields of the Stevens rearrangement due to a possible stabilization and/or activatation of zwiterionic species in solution by the ionic liquid. Several indolizidine moieties were synthesized from quaternary proline derivative (S)-5. © 2009 Sociedade Brasileira de Química.

Más información

Título según WOS: Studies towards the Construction of Quaternary Indolizidines by [2,3]-Sigmatropic Rearrangement Cocatalyzed by Ionic Liquid
Título según SCOPUS: Studies towards the construction of quaternary indolizidines by [2,3]-sigmatropic rearrangement cocatalyzed by ionic liquid
Título de la Revista: JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
Volumen: 20
Número: 5
Editorial: SOC BRASILEIRA QUIMICA
Fecha de publicación: 2009
Página de inicio: 813
Página final: 819
Idioma: English
Notas: ISI, SCOPUS