Studies toward Total Synthesis of Divergolides C and D

Abstract

A facile synthesis of the western segment of divergolides C and D has been developed. Exploratory studies with two disconnections, i.e., <i>C4–C5 </i>vs<i> C5–C6</i>, for elaboration of the ansa bridge to the sterically demanding hexasubstituted naphthalenic aromatic core using a chiral synthon assembled from d-glucose via a stereoselective Johnson orthoester rearrangement is described. The studies set the stage for the completion of the total synthesis of the biologically important novel ansamycins, divergolides C and D, and their structural congeners