Lewis-Acid Catalyzed Tandem Reaction Diels-Alder-[3,3] Sigmatrophic Shift between Buta-1,3-Dienyl Thiocyanic Acid Ester and Acryloyl Chloride-Application in the Synthesis of 2-Azabicyclo[2.2.2]Oct-5-Ene Derivatives

Buta-1,3-dienyl thiocyanic acid ester reacts with acryloyl chloride in presence of Lewis acid catalysts to produce directly the rearranged product of type 3b via a combination of a Diels-Alder reaction with a [3,3] sigmatropic shift; the 1,4-substituted cyclohexene is easily transformed into the 2-azabicyclo[2.2.2]oct-5-ene derivative 6b, which has been used as precursor for the synthesis of the lbogamin skeleton.