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Helicenes: Thermally induced intramolecular 4 + 2 cycloadditions involving the [6]helicene skeleton

par Martin, Richard ;Jespers, Jacques;Defay, Nicole
Référence Helvetica chimica acta, 58, 3, page (776-779)
Publication Publié, 1975

Article révisé par les pairs

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Résumé :

Treatment of dl‐1‐formyl[6]helicene (1) with the ylid of (EtO)2P(O)CH2CO2Et in boiling C6H6 gave a mixture of two dl epimeric cycloaddition products: trans‐2a (80%) and cis‐2b (12%) An X‐ray diffraction study (Van Meerssche et al. [2]) fully confirmed the structure and the stereochemistry assigned to the most abundant stereoisomer 2a by UV., 1H‐INDOR, NOE and catalytic hydrogenation of the non‐benzenoid double bonds. Copyright © 1975 Verlag GmbH & Co. KGaA, Weinheim