An Approach to the Stereoselective Synthesis of Nidifocene. II. Total Synthesis of (.+-.)-Dehalogenonidifocene.

Abstract

The total synthesis of (±)-dehalogenonidifocene (3), a potential key intermediate for the total synthesis of(±)-nidifocene (1), is described, in which the key steps are the construction of the basic tricyclic skeleton and the regioselective introduction of the double bond. Construction of the tricyclic skeleton could be achieved by the intramolecular Michael-type addition of the hydroxyl group of the exo-methylene compound 6, and the reduction of the conjugated diene moiety of 9 with ytterbium in liqud ammonia afforded the target molecule in a regioselective manner.