ABSTRACT
Photochemical reactions of the carbonyl group are among the most extensively investigated areas of organic photochemistry. In this chapter, the regioselective route to a variety of carbocyclic and heterocyclic compounds by means of the Norrish/Yang reaction are discussed. The main emphasis is on preparative applications. First, the history of this reaction is briefly outlined. In 1934, Norrish and Appleyard observed, upon irradiation of aliphatic ketones, a cleavage reaction providing products whose alkyl chain was cleaved between the
α
- and the
β
-carbon atom with respect to the carbonyl group.
