wherein X3 and Y represent a leaving group such as a halogen atom, a mesyloxy group or a tosyloxy group; R3 represents a lower alkyl group or a halo (lower alkyl) group; R4 represents a methyl group or an ethyl group; R5 represents a lower alkyl group; one of Q8 and T8 represents a 2,3,4,6-tatra-O-acetyl-??-D-glucopyranosyloxy group, while the other represents a lower alkyl group or a halo(lower a