Syntheses of Optically Pure Conduramines via the Strategy of Hetero Diels-Alder Reaction of Masked o-Benzoquinones with Homochiral Nitroso Dienophiles

Highly stereoselective hetero Diels-Alder reactions of masked o-benzoquinones (MOBS) with homochiral nitroso dienophiles are described along with their application in the syntheses of (+)-ent-conduramine F-1, (+)-condurannine E-1, (-)-conduramine A-1, (+)-conduramine A-1 tetraacetate, and (-)-ent-conduramine A-1 tetraacetate.