Deconstruction-reconstruction strategy for accessing valuable polyketides. Preparation of the C15-C24 stereopentad of discodermolide.

An advanced, known intermediate for discodermolide synthesis was prepared by an efficient sequence from the readily available fermentation product oleandomycin. The scheme makes use of a new method for the direct cleavage of aminoglycosides, a critical double-bond isomerization, and a selective protection of two of three hydroxyl groups in a modified oleandolide. This synthesis illustrates a new strategy, "deconstruction-reconstruction", for accessing stereochemically complex polyketide building blocks.