1,3-Dipolar Addition of Methyl α-Diazoacetoacetate to Enamines:A New Synthetic Route to 5-Amino-4,5-dihydrofurans

摘要

The reaction of methyl a-diazoacetoacetate with enamines catalyzed by dirhodium and copper complexes underwent formal 1,3-dipolar addition to give 5-amino-4,5-dihydrofurans in moderate yields. The reaction was suggested to proceed via a nucleophilic addition of enamines to metal-carbenes and a subsequent intramolecular cyclization of the resulting zwitterionic intermediates.