Light‐Induced Formation of Acids from Cyclic Ketones

Ultraviolet irradiation of aqueous solutions of cyclic ketones having a tetrahedral carbon atom in at least one of the two positions adjacent to the light‐absorbing carbonyl group results in ring opening accompanied by the formation of a carboxylic acid. Cyclohexadienones which are blocked in the ortho‐position are converted to hexadienoc acids. Cycloalkanones give saturated carboxylic acids and, in the presence of oxygen, also some unsaturated ones. The scope of the reactions is illustrated, and favorable conditions are described. The structure of the products and the route by which they are presumably formed are discussed.