Microwave-assisted click synthesis of levoglucosan triazolyl glycoconjugates using ascorbyl palmitate sodium salt (Asp-Na) as a green Co-catalyst.

Ascorbyl palmitate sodium salt (Asp-Na) 2 has been found to be a highly effective co-catalyst in copper catalyzed azide-alkyne cycloaddition (CuAAC) reactions under microwave (MW) condition. This co-catalyst provides a more cost-efficient option compared to sodium ascorbate by reducing the stoichiometric amount of ascorbic acid required for the CuAAC reaction. With its palmitate side chain, Asp-Na 2 acts as a surfactant by improving the solubility of substrates, particularly the lipophilic compounds. Notably, it can be obtained in high purity by semi-synthesis from non-edible oils, aligning with the sustainable practices. Application of 2 in CuAAC reaction of levoglucosan based terminal alkyne (3) and azido-sugars (4) furnished the corresponding triazolyl glycoconjugates (5) in yields ranging between 70 and 90 %.