This thesis mainly deals with various aspects of xanthate radical chemistry. The first chapter is a general introduction to radical chemistry and provides an overview of the xanthate radical chemistry. The next chapter presents a new methodology for the synthesis of polycyclic aromatic compounds from strained epoxy-olefins. The third chapter describes the total synthesis of the purported structure of flossonol and of one of its isomers and concludes with the resolution of the structure of the natural product. The next section presents the study of different strategies for the synthesis of pseudoptéroxazole. In this work, a method of net contra-thermodynamic isomerization of carbon- carbon trisubstituted endocyclic double bonds has been deve...