Spiroleucettadine: synthetic studies and investigations towards structural revision

Synthetic efforts towards spiroleucettadine are described, including the enantioselective synthesis of the presumed biosynthetic precursor. High level density functional theory calculations were used to predict the 13C NMR shifts of possible alternative structures and, along with a re-evaluation of the available NMR data, allow the proposal of revised structures for this spirocyclic alkaloid.