An unusually selective photo-induced rearrangement of 4-alkoxycarbonyl-5-formyl-2, 3-dihydro-6H-1, 3-oxazines. A new route to preparation of condensed lactones

V Oremus, L Fišera, HJ Timpe…

Index: Oremus, Vladimir; Fisera, Lubor; Timpe, Hans-Joachim; Lammel, Ute Collection of Czechoslovak Chemical Communications, 1988 , vol. 53, # 12 p. 3171 - 3178

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Abstract

Abstract 3-R-Alkoxycarbonyl-5-formyl-2, 3-dihydro-6H-1, 3-oxazines IIa-IIc (R= methyl, ethyl, isopropyl) as primary photoproducts formed by a rearrangement of 3-R-alkoxycarbonyl-3a, 4, 6, 6a-tetrahydrofuro [3, 4-d] isoxazoles Ia-Ic undergo cyclization to bicyclic lactones IIIa-IIIc due to further irradiation. The photochemical transformation of compounds II into III constitutes a new kind of photo-induced rearrangement. The quantum yields are very little ...