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چکیده
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Dimethyl 2-(aryloxy)fumarates and dimethyl 2-(alkyl- or arylthio)fumarates are shown to be efficient dipolarophiles in 1,3-dipolar cycloaddition reaction with azomethine ylides, which are generated by the reaction of isatin with the secondary amino acids proline or sarcosine. In these reactions, dimethyl 2-(alkyl- or arylthio)fumarates afforded spirooxindolopyrrolizidines or -pyrrolidines in high yields with excellent regioselectivities, while dimethyl 2-(aryloxy)fumarates produced mixtures of regioisomers. DFT calculations at the B3LYP/6-31G(d,p) level were consistent with the observed results. Tri- and tetracyclic compounds were obtained through regio- and stereoselective intramolecular cycloaddition of O-vinylic salicylaldehyde with secondary amino acids
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