Light-Induced Formation of Acids from Cyclic Ketones

✍ Scribed by Prof. Dr. G. Quinkert

• Publisher: John Wiley and Sons
• Year: 1965
• Tongue: English
• Weight: 1008 KB
• Volume: 4
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.196502111

✦ Synopsis

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 un- saturated 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.

I. Introduction

Much work has recently been carried out in

the field of organic photochemistry, since both efficient chromatographic methods capable of separating complex mixtures of products, and serviceable light sources [*] are now available. Photochemical reactions are no longer curiosities, even in the syntheses of natural products. A few examples may serve to illustrate this: e-l 1 Scheme I. Principle of the Barton reaction [l].