A convenient synthetic strategy has been developed for the synthesis of a pentasaccharide related to the cell wall O‐polysaccharide of Acinetobacter baumannii (A. baumannii) 90 in very good yield applying a stereoselective [3+2] block glycosylation reaction. The synthesis of the target pentasaccharide was challenging due to the presence of a rare sugar, 4‐amino‐4‐deoxy‐D‐fucose and several α‐glycosidic linkages in it. The construction of 1,2‐cis glycosyl linkages were achieved using a combination of copper(II) bromide and tetra‐n‐butylammonium bromide (TBAB) or a combination of N‐iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) as thiophilic glycosylation activator. Perchloric acid supported over silica (HClO4‐SiO2) mediated orthogonal glycosylation reaction has been carried out using glycosyl trichloroacetimidate derivative as donor and thioglycoside as acceptor.

中文翻译：

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含有与鲍曼不动杆菌90细胞壁O-多糖相关的稀有糖4-氨基-4-脱氧-D-岩藻糖的五糖的收敛合成

开发了一种方便的合成策略来合成与细胞壁相关的五糖氧‐多糖鲍曼不动杆菌(鲍曼不动杆菌) 90，采用立体选择性 [3+2] 阻断糖基化反应，产率非常高。由于其中存在稀有糖、4-氨基-4-脱氧-D-岩藻糖和多个 α-糖苷键，目标五糖的合成具有挑战性。 1,2-的构建顺式糖基连接是通过使用溴化铜（II）和四氢呋喃的组合来实现的。n‐丁基溴化铵 (TBAB) 或其组合氮‐碘代琥珀酰亚胺 (NIS) 和三氟甲磺酸三甲基硅酯 (TMSOTf) 作为亲硫性糖基化激活剂。二氧化硅负载高氯酸 (HClO4‐二氧化硅2）介导的正交糖基化反应已使用糖基三氯乙酰亚胺酯衍生物作为供体和硫代糖苷作为受体进行。