Nucleophilic opening of the 3,5-anhydro ring in 1,2-O-cyclohexylidene- -D-xylofuranose

Abstract

The reactivity of the oxetane ring in 3,5-anhydro-1,2-O-cyclohexylidene- -D-xylofuranose (1) was exemplified by its regiospecific nucleophilic opening. The action of concentrated hydrobromic or hydroiodic acid on 1 resulted in the exclusive formation of the 5-deoxy-5-halo derivatives, while the action of acetyl chloride or acetyl bromide yielded the corresponding 3-O-acetyl-5-deoxy-5-halo derivatives in 70 - 90 % yield. Under strongly acidic reaction conditions, the protection of the cyclohexylidene acetal function remained intact.