Nilsson U, Wendler A, Magnusson G
Lund Institute of Technology, University of Lund, Sweden.
Acta Chem Scand (Cph). 1994 Apr;48(4):356-61. doi: 10.3891/acta.chem.scand.48-0356.
Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phtha limido-beta-D - glucopyranoside 5 gave methyl 3,6-di-O-benzoyl-2,4-dideoxy-2-phthalimido-beta-D-glucopyranoside 6, which was converted into the corresponding methyl thioglycoside donor 9. Methylsulfenyl trifluoromethane-sulfonate-promoted glycosylation of 2-(trimethylsilyl)ethyl 2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosyl)-bet a-D- galactopyranoside 10, followed by removal of protecting groups gave the 4"-deoxy analogue 12 of the terminal trisaccharide of globotetraose. Silver trifluoromethanesulfonate-promoted glycosylation of the same disaccharide alcohol 10 with 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-alpha/beta-D-glucopyranosyl bromide 13 and 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide 16, followed by deblocking, gave the 2"-hydroxy and 4"-epi analogues 15 and 18, respectively.
3,6-二-O-苯甲酰基-2-脱氧-4-O-咪唑-1-基硫代羰基氧基-2-邻苯二甲酰亚胺基-β-D-吡喃葡萄糖苷5的甲基进行彻底脱氧反应，得到3,6-二-O-苯甲酰基-2,4-二脱氧-2-邻苯二甲酰亚胺基-β-D-吡喃葡萄糖苷6，后者被转化为相应的硫代糖苷供体9。2,3,6-三-O-苄基-4-O-(2,4,6-三-O-苄基-α-D-吡喃半乳糖基)-β-D-吡喃半乳糖苷10在甲亚磺酰基三氟甲磺酸酯促进下进行糖基化反应，随后脱去保护基，得到球四糖末端三糖的4''-脱氧类似物12。相同的二糖醇10在三氟甲磺酸银促进下与3,4,6-三-O-乙酰基-2-脱氧-2-邻苯二甲酰亚胺基-α/β-D-吡喃葡萄糖基溴13和2,3,4,6-四-O-乙酰基-α-D-吡喃半乳糖基溴16进行糖基化反应，随后脱保护，分别得到2''-羟基类似物15和4''-表位类似物18。
