The xanthate route to six-membered carbocycles

Abstract

Convergent routes to various six-membered carbocyclic architectures exploiting the unique radical chemistry of xanthates are described in this brief review. Three approaches are discussed. The first is the modification of existing cyclohexane building blocks, namely, cyclohexanones, cyclohexenones and cyclohexenes. The second deals with the construction of six-membered carbocycles by associating the chemistry of xanthates with classical ionic reactions, especially the Robinson annulation, the Michael addition and the Horner–Wadsworth–Emmons condensation. Finally, the third route is the formation of six-membered rings by direct six- exo and, but more rarely, six- endo cyclisation modes. Many of the complex structures presented herein would be tedious to obtain by more traditional methods.