The synthesis of polycyclic compounds usually requires numerous synthetic operations in order to construct the desired carbon skeletons. A simple procedure termed a bicycloannulation allows for the generation of one of these ring systems in one synthetic operation. The tricyclo 3.2.1.0(\u272,7) octane ring system incorporates a two carbon bridge cross a cyclohexane ring which includes at one end a cyclopropane ring. This tricyclic carbon skeleton is a highlighting feature of a number of terpenoids, including the sesquiterpene cycloseychellene. Beginning with a substituted cyclohexenone, the bicycloannulation allows for the construction of all but one of the rings in this tetracyclic sesquiterpene. A number of approaches for the formation of the remaining ring are discussed.;Liquid-ammonia reduction of the tricyclo 3.2.1.0(\u272,7) octane ring system allows easy access into the bicyclo 2.2.2 octane ring series. With the use of this technique, work towards the total synthesis of patchouli alcohol is discussed as well as a formal synthesis of this commercially valuable compound
