Accessing C-1 Phosphonylated 2-Acylamino Uronic Acids via 2-Nitro-glycals

Abstract

Two approaches are described for the synthesis of 2-acylamino uronic acid glycosyl phosphonates from readily accessible D-glucal. The first approach that entailed oxidation of the C-6 hydroxyl group followed by phosphonylation of the uronate 2-nitro-glycal, resulted in the formation of the ߭L-gulo-configured phosphonate. Reversing the reaction order resulted in the exclusive formation of the ߭D-gluco-configured phosphonate. In both cases the thermodynamic 1,2-trans-di-equatorial phosphonylation product is obtained.