Reactions de cyclisation photochimique D'α-alcoxy cyclohexenones

α-Ketooxetanes and α-alkylidene oxetanols are the main products of the photolysis of 2-alkoxy 2-cyclohexenones; γ-hydrogen abstraction and cyclization of the intermediate biradical are general processes for these enones. Regioselectivity of the reaction and several aspects of the photolysis of a ketooxetanes are discussed. The corresponding 2-alkoxy cross-conjugated dienones rearrange in cyclopropyl ketones when photolyzed in the same conditions.