A highly regioselectivereductivecleavage of the bis-benzylidene acetal of d-mannitol was performed using a BF3·Et2O/Et3SiH reagent system. A chiral intermediate 6 thus obtained was efficiently utilized in the stereoselective synthesis of the anticancer agent OGT2378 (3) and glycosidase inhibitor derivative N-tosyl 1,4-dideoxy-1,4-imino-l-xylitol (22). Chemoselective reduction of azido epoxide 10