A New and Stereoselective Glycosylation and Synthesis of Origosuccaride

2-O-苯甲酰基-3，4，用催化量的三氟甲磺酸（TfOH）成功地合成了6-三-O-苄基-β-D-葡萄糖基氟与几种糖基受体的糖基化反应，用催化量的三苯甲基四氢呋喃成功地合成了几种糖基氟与β-葡萄糖基受体的立体选择性糖基化反应以TrB（C_6F_5）_4为催化剂，在特戊腈-三氟甲苯（BTF）1：5的混合溶剂中，糖基化反应顺利进行，产率高，β-立体选择性高。进一步建立了该催化剂的武装-解除武装策略的糖基化反应。类似地，TfOH，一种强质子酸，用包括硫代糖苷在内的各种糖基受体处理具有2-O-苯甲酰基的β-糖基氟化物时，催化的糖基化以良好至优异的产率得到相应的β-糖苷。乙硫基邻苯二甲酰亚胺（PhthNSEt）和催化量的TrB（C_6F_5）_4，并成功地应用于一锅法“武装-解除武装”顺序合成三乙胺。在乙醚中，以催化量的TfOH为催化剂，在MS 5 Ⅲ分子筛存在下，成功地合成了6-四-O-苄基-β-D-吡喃葡萄糖基氟，以高产率得到了相应的α-连接二糖，并将其应用于一锅法序贯合成三乙胺。

Stereoselective glycosylation of 2-O-benzoyl-3,4,6-tri-O-benzyl-β-D-glucosyl fluoride with several glycosyl acceptors is successfully carried out by using a catalytic amount of trifluoromethanesulfonic acid (TfOH).A catalytic and stereoselective glycosylation of several glycosyl acceptors with β-glycosyl fluoride is successfully performed by using a catalytic amount of trityl tetrakis(pentafluorophenyl)borate [TrB(C_6F_5)_4] or TfOH.When TrB(C_6F_5)_4 was used as a catalyst, the glycosylation proceeded smoothly to afford the glycosides in high yields with high β-stereselectivities in pivalonitrile-trifluoromethylbenzene (BTF) 1 : 5 mixed solvent. Further, the glycosylation reaction of armed-disarmed strategy with this catalyst was established. Similarly, TfOH, a strong protic acid, catalyzed glycosylation afforded the corresponding β-glycosides in good to excellent yields on treating β-glycosyl fluorides having 2-O-benzoyl group with various glycosyl acceptors including thioglycosides.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 TrB(C_6F_5)_4, and is successfully applied to one-pot "armed-disarmed" sequential synthesis of trisaccharides.Stereoselective glycosylation of several glycosyl acceptors with 2,3,4,6-tetra-O-benzyl-β-D-glucopyranosyl fluoride was successfully carried out in diethylether by using a catalytic amount of TfOH in the coexistence of molecular sieve 5Å (MS5Å) to afford predominantly the corresponding α-linked disaccharides in high yields, which was applied to one-pot sequential syntheses of trisaccharides.