Li Z J, Huang H Q, Cai M S
School of Pharmaceutical Sciences, Beijing Medical University, China.
Carbohydr Res. 1994 Dec 16;265(2):227-36. doi: 10.1016/0008-6215(94)00226-6.
Allyl 2-O-benzoyl-4,6-O-benzylidene-alpha-D-glucopyranoside (3), obtained by selective benzoylation of allyl 4,6-O-benzylidene-alpha-D-glucopyranoside (2) with benzoyl chloride-imidazole in anhydrous chloroform, reacted with 2, 3, 4-tri-O-benzoyl-alpha-L-rhamnopyranosyl bromide to give a disaccharide derivative (4), and an important intermediate (5) was obtained by cleavage of its acetal. Treatment of 5 with a series of glycopyranosyl bromides, protected by acetyl or benzoyl groups in benzene-nitromethane in the presence of Hg(CN)2 as a catalyst afforded four trisaccharides (6-9). The disaccharide (5) and trisaccharides (6-9) constitute the sugar cores of phenylpropanoid glycosides. A new glycosyl anomeric leaving group, trichloroacetoxy, was employed to prepare the disaccharide (4) and trisaccharides residue (8) efficiently and with high stereoselectivity.
烯丙基 2-O-苯甲酰基-4,6-O-亚苄基-α-D-吡喃葡萄糖苷（3）由烯丙基 4,6-O-亚苄基-α-D-吡喃葡萄糖苷（2）在无水氯仿中用苯甲酰氯-咪唑进行选择性苯甲酰化反应制得，它与 2,3,4-三-O-苯甲酰基-α-L-鼠李吡喃糖基溴反应生成二糖衍生物（4），通过其缩醛的裂解得到重要中间体（5）。在 Hg(CN)₂ 作为催化剂的存在下，将 5 与一系列被乙酰基或苯甲酰基保护的吡喃糖基溴在苯-硝基甲烷中反应，得到四种三糖（6 - 9）。二糖（5）和三糖（6 - 9）构成了苯丙素苷的糖核。采用一种新的糖基异头离去基团三氯乙酰氧基高效且高立体选择性地制备了二糖（4）和三糖残基（8）。
