Reaction of aldose derivatives with dimethyl(diazomethyl)phosphonate, generated in situ by methanolysis of dimethyl(1-diazo-2-oxopropyl)phosphonate leads to glyco-1-ynitols derivatives. This synthesis presents two main advantages: it is a one-step synthesis, and tolerates free hydroxyl groups. (C) 2000 Elsevier Science Ltd. All rights reserved.