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Stereoselective glycosylation of several glycosyl acceptors with 2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl fluoride was successfully carried out in diethyl ether by using a catalytic amount of trifluoromethanesulfonic acid (TfOH) in the coexistence of molecular sieve 5A (MS5A) to afford predominantly the corresponding α-linked disaccharides in high yields, which was applied to one-pot sequential syntheses of trisaccharides.

Glycosylation of the ‘armed’ thioglycoside with various glycosyl acceptors is promoted by using a combination of stoichiometoric amount of N-(ethylthio)phthalimide (PhthNSEt) and catalytic amount of trityl tetrakis(pentafluorophenyl)borate [TrB(C6F5)4], and is successfully applied to one-pot ‘armed–disarmed’ sequential synthesis of trisaccharides.

A combined use of trityl tetrakis(pentafluorophenyl) borate [TrB(C6F5)4], iodine (I2) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) effectively activates “disarmed” thioglycosides to afford the corresponding disaccharides in high yields on treatment with several glycosyl acceptors.

The trityl tetrakis(pentafluorophenyl)borate [TrB(C6F5)4] catalyzed stereoselective synthesis of various disaccharides was successfully carried out by treating a new 2-O-acyl-protected glycosyl donor, 3,4,6-tri-O-benzyl-2-O-p-toluoyl-β-D-glucopyranosyl phenylcarbonate, with several glycosyl acceptors, thioglycosides, affording the corresponding disaccharides in high yields.

New highly effective promoter system for the glycosylation of thioglycoside, the combined use of stoichiometric amount of either N-iodosuccinimide or N-bromosuccinimide and a catalytic amount of TrB(C6F5)4, was developed and was successfully applied to the one-pot sequential synthesis of trisaccharides. In the first glycosylation step, 3,4,6-tri-O-benzyl-2-O-p-toluoyl-β-D-glucopyranosyl phenylcarbonate was treated with thioglycosides in the presence of a catalytic amount of TrB(C6F5)4 alone, and the following glycosylation with methyl α-D-glycosides was carried out by further addition of either N-iodosuccinimide or N-bromosuccinimide to the initially resulted reaction mixture to afford the corresponding trisaccharides in one-pot manner.

A one-pot synthesis of trisaccharides was successfully carried out by combination of two types of the trityl tetrakis(pentafluorophenyl)borate catalyzed stereoselective glycosylation reactions. Selective activation of a glycosyl phenyl carbonate in the presence of a thioglycoside allows two successive glycosyl coupling in one-pot manner to afford several protected trisaccharides, Glcβ1-6Glcβ1-6Glc, in good to high yields.

A catalytic and stereoselective glycosylation of glycosyl fluorides with several glucosides is successfully performed by using a catalytic amount of trityl tetrakis(pentafluorophenyl)borate.

Several 2-deoxy-α-D-glucopyranosides are stereoselectively synthesized in high yields by glycosylation of various alcoholic nucleophiles with 3,4,6-tri-O-benzyl-2-deoxy-glucopyranose using a catalytic amount of trityl tetrakis(pentafluorophenyl)borate.

The anomerization reactions of several β-D-glucopyranosides proceed smoothly in the coexistence of MgBr2·OEt2 and a catalytic amount of titanium(IV)halides to afford the corresponding α-D-glucopyranosides. The desired alkyl α-glucosides and α-anomer of disaccharides such as Glcα1-6Glc were obtained in high yields with high stereoselectivities.

A new efficient method for the catalytic stereoselective synthesis of various α-L-fucosides by using an easily available and stable glycosyl donor, 2,3,4-tri-O-benzyl-L-fucopyranosyl methoxyacetate, is established. Also, trimethylsilyl trifluoroacetate and lithium perchlorate are found to be effective additives in the synthesis of Fucα1-3GlcNAc and Fucα1-4GlcNAc linkages.