Dearomatization reactions: An overview

Abstract

An attractive general strategy for construction of complex organic molecules exploits the concept of dearomatization to facilitate carbon-carbon and carbon-heteroatom bond formation. In addition, dearomatization reactions often convert locally achiral aromatic or polyaromatic ring systems into alicyclic derivatives possessing stereogenic centers. Thus, dearomatization tactics present opportunities for diastereoselective and enantioselective transformations of great value in organic synthesis. An overview of commonly used dearomatization reactions of carbocyclic arenes is presented in this chapter, with particular emphasis placed upon synthetic applications featuring asymmetric variants. The material is organized according to mechanistic considerations and includes discussions of both conventional and transition metal-mediated processes. Dearomatization reactions of heteroaromatic ring systems are beyond the scope of this chapter. Reductive dearomatization reactions (e.g., Birch reduction) also are not discussed as this subject is addressed in Chapter 13 (Reduction/Hydrogenation of Aromatic Rings). While synthetic applications of oxidative dearomatization are described, the reader is referred to Chapter 14 (Oxidation of Aromatic Rings) for a more thorough treatment of arene oxidation.