Total synthesis of (-)- and ent-(+)-vindoline

reaction: see text] Two exceptionally concise total syntheses of (-)- and ent-(+)-vindoline are detailed enlisting a diastereoselective tandem 4 + 2]/3 + 2] cycloaddition of a 1,3,4-oxadiazole. The unique reaction cascade assembles the fully functionalized pentacyclic ring system of vindoline in a single step that forms four C-C bonds and three rings while introducing all requisite functionality and setting all six stereocenters within the central ring including three contiguous and four total quaternary centers.