Nitrone 3 analogue of 5-deoxy-l-lyxose was derived from d-ribose. Its reduction with aqueous SO2 gave the corresponding 4-amino-sugar 2, a potent α-l-fucosidase inhibitor. 1,3-Dipolar cycloaddition of 3 with alkenes allowed the synthesis of acetohydroxamic acid and ethane–phosphonate derivatives. Hydroxy-ethane derivative 15 is a nanomolar α-l-fucosidase inhibitor.