Kazuya Takeuchi

A Catalytic and Stereoselective Glycosylation withβ-Glycosyl Fluorides

A catalytic and stereoselective glycosylation of several glycosyl acceptors with β-D-glycosyl fluoride was successfully performed in the presence of a catalytic amount of trityl tetrakis(pentafluorophenyl)borate (TrB(C6F5)4) or trifluoromethanesulfonic acid (TfOH). When TrB(C6F5)4 was used as a catalyst in the solvent pivalonitrile/(trifluoromethyl)benzene 1 : 5, the glycosylation proceeded smoothly to afford the glycosides in high yields with high β-D-stereoselectivities (see Table 3). Further, the glycosylation by the armed-disarmed strategy in the presence of this catalyst was established (see Table 4). Similarly, glycosylation catalyzed by the strong protic acid TfOH afforded the corresponding β-D-glycosides in good-to-excellent yields on treating β-D- glycosyl fluorides having a 2-O-benzoyl group with various glycosyl acceptors including thioglycosides (see Tables 6 and 7).