Stereoselective One-Step Construction of Vicinal Quaternary and Tertiary Stereocenters of the 5,10b-Ethanophenanthridine Skeleton: Total Synthesis of (±)-Maritidine

The challenging vicinal quaternary and tertiary stereocenters of the 5,10b-ethanophenanthridine skeleton are created in a single step utilizing intramolecular [3 + 2]-cycloaddition of nonstabilized azomethine ylide as the key step. The application of the chemistry is demonstrated by synthesizing (+/-)-maritidine.