Nashed M A, Anderson L
Carbohydr Res. 1983 Mar 16;114(1):53-61. doi: 10.1016/0008-6215(83)88172-5.
The selectively benzylated glycoside allyl 2-acetamido-4,6-di-O-benzyl-2-deoxy-beta-D-galactopranoside (4) was prepared from the corresponding derivative of 2-acetamido-2-deoxy-D-glucose via the p-bromobenzenesulfonate and the benzoate. 2-O-Benzoyl-3,4,6-tri-O-benzyl-alpha-D-galactopyranosyl (10) was obtained from allyl 6-O-benzyl-2-O-(2-butenyl)-alpha-D-galactopyranoside via known intermediates. To complete the sequence, the 1-propenyl 3,4,6-tri-O-benzyl galactoside was successively converted into the 2-benzoate, the free sugar, and the chloride 10. A fully protected form (11) of the trisaccharide alpha-L-Fucp-(1 leads to 2)-beta-D-Galp-(1 leads to 4)-D-GalNAc was then synthesized by coupling 10 to 4, partially deblocking the disaccharide product, and L-fucosylating the resulting intermediate. Cleavage of the O-benzyl groups from 11, with concomitant saturation of the allyl group, gave the propyl beta-glycoside of the unsubstituted trisaccharide.
选择性苄基化糖苷烯丙基2-乙酰氨基-4,6-二-O-苄基-2-脱氧-β-D-吡喃半乳糖苷（4）由2-乙酰氨基-2-脱氧-D-葡萄糖的相应衍生物经对溴苯磺酸酯和苯甲酸酯制备而成。2-O-苯甲酰基-3,4,6-三-O-苄基-α-D-吡喃半乳糖基（10）由烯丙基6-O-苄基-2-O-（2-丁烯基）-α-D-吡喃半乳糖苷通过已知中间体获得。为完成该序列，将1-丙烯基3,4,6-三-O-苄基半乳糖苷依次转化为2-苯甲酸酯、游离糖和氯化物10。然后通过将10与4偶联、部分脱保护二糖产物以及对所得中间体进行L-岩藻糖基化反应，合成了三糖α-L-岩藻糖基-（1→2）-β-D-吡喃半乳糖基-（1→4）-D-乙酰半乳糖胺的完全保护形式（11）。从11上裂解O-苄基，同时使烯丙基饱和，得到未取代三糖的丙基β-糖苷。
