Multicomponent 1,3-dipolar cycloaddition of azomethine ylides generated from 2,2-dimethoxyacetaldehyde or phenylglyoxal

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

Congreso; VIII School of organometallic chemistry Marcial Moreno Mañas; 2015

Multicomponent reactions are frequently found in the literature allowing high atom economy. We have recently reported the diasteroselective 1,3-dipolar cycloaddition using ethyl glyoxilate as aldehyde together with alfa-amino esters (derived from glycine, alanine, phenylalanine and phenylglycine) and different dipolarophiles. Microwave-assisted heating processes gave better results than conventional heating ones, afforfing endo-cycloadducts as major stereoisomers with 2,5-cis-relative arrangement through the W-shaped dipole.In this work, we have employed densely functionalizaed aldehydes in order to obtain polysubstituted proline derivatives with functionalized groups, different to conventional aromatic substituents, bonded at the 5 position. The reaction of 2,2-dimethoxyacetaldehyde or phenylglyoxal with alfa-amino esters and dipolarophiles afforded new proline ester derivatives 1 or 2, respectively, in good chemical yields and very high endo-diastereoselctivities.