Synthesis and Chemical Behaviour of 4, 5-Dideoxy-4, 5-Epithio-2, 3-DI-0-Methanesulfonyl-L-Xylose Dimethyl Acetal

ABSTRACT

Selective substitution of the primary sulfonate group in 2, 3, 4, 5-tetra-0-methanesulfonyl-D-arabinose dimethyl acetal (1) gives 5-S-acetyl-2, 3, 4-tri-0-methanesulfonyl--5-thio-D-arabinose dimethyl acetal (2) which is further converted into the title compound (3). Reductive desul-furization of 3 afforded deoxy dimethyl acetal derivatives 5 and 6 in a low yield. Unsaturated monosaccharide derivative 7 was obtained as the only reaction product from 3 with triphenylphosphine. Catalytic hydrogenation of 7 gave dideoxy-sugar 6 in a satisfactory yield. Finally, epi-sulfide 3 with acetyl chloride afforded 4-chloro-4-deoxy derivative 4, which can be recycled into the starting 3.