Molecular diversity of the three-component reaction of α-amino acids, dialkyl acetylenedicarboxylates and N-substituted maleimides

The one-pot three-component reaction of secondary alpha-amino acids, including proline, thiazolidine-4-carboxylic acid, and piperidine-2-carboxylic acid sarcosine with dialkyl acetylenedicarboxylate and N-substituted maleimides in refluxing ethanol afforded functionalized pyrrolo[3,4-a]pyrrolizines, pyrrolo[3',4':3,4]pyrrolo[1,2-c]thiazoles, pyrrolo[3,4-a]indolizines and octahydropyrrolo[3,4-c]pyrroles in good yields and with high diastereoselectivity. On the other hand, the similar three-component reaction containing primary alpha-amino acids, such as glycine, alanine, phenylalanine and leucine, with N-substituted maleimides and two molecules of dialkyl acetylenedicarboxylate obtained the corresponding hexahydropyrrolo[ 3,4-c] pyrrol-2(1H)-yl)maleates.