Neighboring group participation of 9-anthracenylmethyl group in glycosylation: preparation of unusual C-glycosides

[reaction: see text] A coupling of 2-O-arylmethylated D-glucose-derived thioglycosides with various alcohols in the presence of DMTST as an activator is described. The requisite glycosyl donors are efficiently prepared by one-pot procedures. When the aryl groups are phenyl, p-methoxyphenyl, 1-naphthyl, and 2-naphthyl groups, a mixture of alpha- and beta-anomeric O-glycosides is obtained under the conditions, whereas when the aryl group is the 9-anthracenyl group, a highly stereoselective formation of the unusual C-glycosides in good yields via neighboring group participation of the 9-anthracenylmethyl group followed by coupling with a variety of alcohols is observed. Three new chiral centers including a quaternary carbon are created in one single step.