A sulfolene-based intramolecular Diels–Alder approach to the synthesis of manzamine A

Abstract
Synthetic studies towards manzamine A are described. A tandem sulfolene SO2 extrusion intramolecular Diels–Alder cyclisation gave the C-5 epimer of the manzamine tricyclic ABC ring system via a C-5 to C-8 diene bearing a C-5/C-6 Z-alkene.