Kedarcidin chromophore: synthesis of its proposed structure and evidence for a stereochemical revision

Abstract

A convergent, enantioselective synthesis of the proposed structure of kedarcidin chromophore (1) is described. The route is 24 steps in the longest linear sequence (beginning with the commercial reagent 2,3-O-isopropylidene-d-erythronolactone) with an average yield of 75% per step (overall yield: 0.1%). Our ¹H NMR data for 1 do not coincide with the data reported for kedarcidin chromophore. We have re-analyzed the original data and here propose a stereochemical revision at position C10, the site of attachment of the l-mycarose carbohydrate residue to the chromophore core (structure 2).