Total Synthesis of Herbicidin C and Aureonuclemycin: Impasses and New Avenues

The undecose nucleoside antibiotics
herbicidin C and aureonuclemycin
are biologically highly active and represent challenging targets for
total synthesis. Herein, the gradual evolution of our synthetic strategy
toward these natural products is described in detail. The initial
route encompasses metalate addition chemistry but suffers from poor
stereochemical control. In contrast, the ultimately successful strategy
benefits from a variety of reagent-controlled stereoselective transformations,
including a surprisingly facile and highly diastereoselective N-glycosylation process. The presented work also describes
new building blocks that might find further application in carbohydrate
chemistry.