A novel synthetic approach towards the AB-ring system of 9-azasteroids

Based on a high energy intermediate model for the inhibition of the ergosterol biosynthesis 9-azasteroids represent potential bioactive compounds as antimycotics. Herein, we describe a novel diastereoselective approach towards a substructure containing the AB-ring system bearing an angular methyl group. Utilizing Diels–Alder chemistry for the construction of the A-ring, the heterocyclic system (ring B) was constructed via a reductive cyclization methodology.