ArylC-Glycosides fromO-Glycosyltrichloroacetimidates and Phenol Derivatives with Trimethylsilyl Trifluoromethanesulfonate (TMSOTf) as the Catalyst

The reaction of O-(2,3,4,6-tetra-O-benzyl-α-D-glucopyranosyl) trichloracetimidate (1), as glycosyl donor with phenol and naphthol derivatives 2a-d and 2f-h, as glycosyl acceptors, furnished in the presence of catalytic amounts of TMSOTf the corresponding o-hydroxyaryl C-β-D-glucopyranosides 3a-d, f-h regio- and stereoselectively. The less reactive 4-methoxyphenol (2e), α-naphthol (2i), the hydroxy substituted coumarines 2j, k and the flavone 21 afforded under these conditions O-glycosides 5e, i-l. Hydrogenolytic O-debenzylation of 3a,b,d afforded compounds 4a,b,d.