Synthesis of the polycyclic core of vincorine via cascade reactions

We developed a six-step synthesis of the polycyclic core of vincorine using two cascades of reactions. A cascade of Michael–Mannich reactions was employed for one-pot preparation of a polycyclic intermediate, which was transformed into the desired polycyclic pyrroloindoline ring system using a cascade of methanolysis-N-imine cyclization reactions.