An effective glycosylation procedure for the stereoselective construction of the α-D-GlcN-(14)-D-GlcA/L-IdoA glycosidic linkage found in heparin and heparan sulfate is reported. The condensation occurs between 2-deoxy-2-azido-D-glucopyranosyl (D-GlcN) ortho-hexynylbenzoate donors and uronate acceptors (D-GlcA/L-IdoA) under mild gold(I)-catalyzed conditions. Optimal results are obtained when performing the reaction in CH2Cl2, from -72°C to r.t., in the presence of 4Å MS and under the promotion of Ph3PAuCl/AgOTf or (1,1-bis-(diphenylphosphino)methane)(AuCl)2 (C3)/AgOTf as a source of the gold(I) catalyst. A donor/acceptor ratio of 3/1 as well as a loading of 0.6 eq. of the gold(I) catalyst are essential to attain high yields and α-selectivity, particularly for the [1+1] and [1+2] glycosylations.