Reaction of a series of aminodeoxy-pentitols and -hexitols in anhydrous hydrogen fluoride with formic acid as catalyst gave the corresponding 2,5- and 3,6-anhydro-anlinodeoxyalditols; namely, 1-amino-2,5-anhydro-1-deoxy-D-arabinitol, -D-xylitol, and -D-ribitol; 1-amino-3,6-anhydro-1-deoxy-D-glucitol, -D-mannitol, and -D-galactitol; and 2-amino-3,6-anhydro-2-deoxy-D-glucitol in yields of 95-100%. 1-Amino-1-deoxy-L-rhamnitol and its dimethylamino derivative gave 1-amino-2,5-anhydro-1,6-dideoxy-D-gulitol and 2,5-anhydro-1,6-dideoxy-1-dimethylamino-D-gulitol with configurational inversion at C-5. In all cases the reactive intermediate is believed to be a 4,5- or 5,6-dioxolenium ion, which can react intramolecularly with a hydroxy group to form a five-membered oxolane ring. The dimethylamino-D-gulo-oxolane was converted into a new 3-hydroxymuscarine isomer, namely, 2,5-anhydro-1,6-dideoxy-1-trimethylammonio-D-gulitol chloride. D-arabino-Hexosulose phenylosotriazole gave the corresponding 3,6-anhydro-D-avabino-hexosulose phenylosotriazole. Syntheses of the 1-amino-1-deoxyalditols were performed by reductive amination with benzylamine-sodium borohydride followed by catalytic hydrogenation over Pd-C. (C) 1996 Elsevier Science Ltd.