Multicomponent synthesis of unnatural pyrrolizidines using 1,3-dipolar cycloadditions of proline esters

JOSÉ M. SANSANO-GIL; JUAN MANCEBO ARACIL; CARMEN NÁJERA

Congreso; VII International School on Organometallic Chemistry Marcial Moreno Mañas; 2014

Azabicycles such as pyrrolizidine and indolizidine alkaloids are important natural products and their structural motifs are present in many biologically active compounds. efficient strategies have been developed for the synthesis of different kind of these types of heterocyclic compounds. 1,3-Dipolar Cycloadditions involving azomethine ylides and electrophilic alkenes are good examples for the synthesis of prolines and these types of azabicycles. Specially interesting are multicomponent 1,3-DCgenerating in situ the corresponding azomethine ylide from the carbonyl compound and the amine. In this lecture, the regio- and diastereoselective synthesis of highly substituted pyrrolizidines by the multicomponent 1,3-DC between proline esters, aldehydes and dipolarophiles will be presented. The corresponding highly substituted indolizidines can be also synthesized by the multicomponent 1,3-Dc between pipecolic acid methyl ester hydrochloride, aldehydes, and dipolarophiles.