A concise route to access the key disaccharide repeating unit (IdoA–GlcN) of heparan sulfate is described. The synthesis was accomplished by commercially available diacetone α-D-glucose to functional group transformations, which led to the formation of a L-iduronate donor. This L-iduronate donor was subsequently coupled with a glucosyl acceptor to form the corresponding key disaccharide repeating unit (IdoA–GlcN) of heparan sulfate in good overall yield.