A Catalytic and Stereoselective Glycosylation withβ-Glycosyl Fluorides
摘要:
A catalytic and stereoselective glycosylation of several glycosyl accepters with beta-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 beta-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 beta-D-glycosides in good-to-excellent yields on treating beta-D-glycosyl fluorides having a 2-O-benzoyl group with various glycosyl accepters including thioglycosides (see Tables 6 and 7).
A Catalytic and Stereoselective Glycosylation withβ-Glycosyl Fluorides
摘要:
A catalytic and stereoselective glycosylation of several glycosyl accepters with beta-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 beta-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 beta-D-glycosides in good-to-excellent yields on treating beta-D-glycosyl fluorides having a 2-O-benzoyl group with various glycosyl accepters including thioglycosides (see Tables 6 and 7).