Total synthesis of (-)- and ent-()-vindoline and related alkaloids

A concise 11-step total synthesis of (-)- and ent-()-vindoline is detailed in which the entire pentacyclic skeleton is assembled in a single step tandem [4@]/[3@] cycloaddition cascade of a 1,3,4-oxadiazole. The intramolecular reaction cascade is initiated by an inverse electron demand Diels-Alder reaction of an electron-rich enol ether in which the diene and dienophile substituents complement and reinforce the [4@] cycloaddition regioselectivity dictated by the linking tether.