A new efficient and stereospecific conversion of aminodeoxyalditols into aminoalkyl-substituted tetrahydrofurans

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-aminodeoxyalditols; 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-arabino-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.