Catalytic Asymmetric Assembly of Octahydroindolones: Divergent Synthesis of Lycorine-type Amaryllidaceae Alkaloids (+)-a-Lycorane and (+)-Lycorine

We report the first catalytic asymmetric approach to octahydroindolones and a divergent enantioselective synthesis of perhydroindole alkaloids, as exemplified by lycorine-type Amaryllidaceae alkaloids (+)--lycorane and (+)-lycorine, from a common intermediate by using a highly concise route. The assembly of octahydroindolones employs a catalytic enantioselective 1,4-conjugate addition of nitro dienynes, followed by a TsOH-catalyzed cascade synthesis of highly functionalized enones, and a diastereoselective intramolecular Michael addition.