Multicomponent 1,3-dipolar cycloadditions of azomethine ylides

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

Congreso; Recent Advances in Chemistry (REACH); 2015

Pyrrolidines and pyrrolizidine alkaloids are important natural products by plants against insects and in 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. !,3-dipolar cycloaddition involving azomethine ylides and electrophilic alkenes are good examples for the synthesis of these five membered heterocyclic systems. Specially interesting are multicomponent 1,3-DC generating in situ the corresponding azomethine ylide from the carbonyl compound and the amine. In this lecture, the synthesis of highly substituted pyrrolidines would be described by means of thermal and silver mediated multicomponent 1,3-DC between alfa-amino esters hydrochlorides, dipolarophiles and functionalized aldehydes. ethyl glyoxilate and 2,2-dimethoxyacetaldehyde reacted with ethyl alfa-amino esters hydrochlorides at rt in the presence of Et3N thermally or in the presence of AgOAc at rt with dipolarophiles affording endo-prolines with high 4,5-endo-2,5-cis-diastereoselection. For the synthesis of highly substituted pyrrolizidines, the multicomponent 1,3-DC between proline esters, aldehydes and dipolarophiles to afford will be described.