Annulation of 2H-pyran onto 1-oxa-or 1-azacyclohexane-2, 4-diones and their analogues via sequential condensation with α-substituted enals and 6π- …

…, T Ikemi, W Peng, H Kawafuchi, T Inokuchi

Index: Hossain, Md. Imran; Shaban, Elkhabiry; Ikemi, Taku; Peng, Wei; Kawafuchi, Hiroyuki; Inokuchi, Tsutomu Bulletin of the Chemical Society of Japan, 2013 , vol. 86, # 7 p. 870 - 879

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Abstract

2H-Pyrans are constructed on a 1-oxa-or 1-azacyclohexane-2, 4-dione core via Knoevenagel condensation with enals followed by 6π-electrocyclization, which are readily catalyzed with ethylenediammonium diacetate. This formal [3+ 3] strategy constitutes C–O and C–C bond making and the diastereomer formation is circumvented using 6, 6- disubstitution with the same aryl group in the 1-oxacyclohexane-2, 4-diones. This facile ...