Stereoselective Route to the Ezoaminuroic Acid Core of the Ezomycins^†

Starting from readily available (R)-glycidol, an efficient pathway to a strategically functionalized ezoaminuroic acid derivative of the antifungal ezomycins has been developed. A key transformation in the synthesis involves regio- and stereoselective conversion of the olefinic functionality of a 5,6-dihydropyran-2-one to the C-2, C-3 trans-1,2-amino alcohol moiety as present in ezoaminuroic acid.