AbstractThe C1 and C2 stereocenters of α‐glucosaminides can be prepared by establishing the stereocenters in either order. For the former, a C2‐azido glucosyl donor is prepared first, and the restraining effect of a 4,6‐O‐benzylidene ring is used to induce α‐coupling. For the latter, the C1 linkage is prepared first by use of an n‐pentenyl‐manno‐1,2‐orthoester donor which ensures (a) clean α‐coupling and (b) a convenient C2‐ester. The C2‐ester is replaced with a triflate leaving group, and nucleophilic displacement is effected by use of a hypervalent silicon azide.
摘要 α-
氨基葡萄糖苷的 C1 和 C2 立体中心可以按两种顺序制备。对于前者,首先制备 C2-
叠氮葡萄糖基供体,然后利用 4,6-O-亚苄基环的限制作用诱导 α-偶联。对于后者,首先使用正
戊烯基-甘露-1,2-正酯供体制备 C1 连接,以确保 (a) α 偶联干净利落,(b) C2- 酯方便使用。C2- 酯被三酸酯离去基团取代,并通过使用超价
叠氮化
硅实现亲核置换。