Synlett

Exploring α-Chromonyl Nitrones as 1, 5-Dipoles

K Wittstein, AB García, M Schürmann, K Kumar

Index: Wittstein, Kathrin; Garcia, Ana B.; Schuermann, Markus; Kumar, Kamal Synlett, 2012 , # 2 p. 227 - 232

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Citation Number: 10

Abstract

Abstract N-Phenyl-C-chromonyl nitrones 1 and the allenoate zwitterion 2, generated by addition of phosphine to acetylenedicarboxylates, undergo a cascade reaction sequence involving an unprecedented [5+ 3] annulation followed by deoxygenative rearrangement leading to dihydropyridine-fused benzopyrones. Unusual electronic control by the N- substituents of 1 directs the annulation pathway, leading to two different ring-systems.