Synthesis and Reactivity of Aziridines with Internal Dipolarophiles: An Approach to 1,4-Dihydrochromeno[4,3-b]pyrroles and 3-Methylenechromano[4,3-b]pyrroles

Aziridines derived from 2-(prop-2-yn-1-yloxy)- and 2-(buta-2,3-dien-1-yloxy)chalcones and from benzyl 2-(prop-2-yn-1-yloxy)- and 2-(buta-2,3-dien-1-yloxy)phenylacrylates were prepared in a stereoselective fashion. Their reactivity as azomethine ylide precursors was examined, leading to the synthesis of 1,4-dihydrochromeno[4,3- b ]pyrrole and 3-methylenechromano[4,3- b ]pyrrole derivatives through intramolecular 1,3-dipolar cycloaddition reactions.