Preparation of Multivalent Carbohydrate Mimetics Based on Enantiopure 1,2-Oxazines by Sonogashira Coupling and Subsequent Reductive Ring-Opening
Preparation of Multivalent Carbohydrate Mimetics Based on Enantiopure 1,2-Oxazines by Sonogashira Coupling and Subsequent Reductive Ring-Opening
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DOI：
10.1002/ejoc.201403186
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发表时间：
2015-01-01
影响因子：
2.8
通讯作者：
Reissig, Hans-Ulrich
中科院分区：
文献类型：
--
作者：
Kandziora, Maja;Reissig, Hans-Ulrich
提出了一种模块化方法，以芳基c -糖苷及其多价类似物。Sonogashira偶联反应将含对溴苯基取代基的对不纯双环1,2-恶嗪衍生物与炔烃连接起来。随后的氢解或氢解和二碘化钐介导的还原反应组合将偶联产物转化为具有D-talose结构的新的非天然氨基碳水化合物模拟物。通过激光偶联反应，我们得到了带有1,3-二炔连接剂的产物及其衍生的二价化合物。化合物8与几种碘苯衍生物通过Sonogashira反应，高收率地制备了二价、三价和四价化合物。随后的还原过程将1,2-恶嗪部分转化为相应的氨基吡喃。在大多数情况下，通过遵循适当的策略，如适当的步骤序列或中间体的乙酰化，可以解决严重的纯化问题。
A modular approach to aryl C-glycosides and their multivalent analogues is presented. Sonogashira coupling reactions connected the key compounds, enantiopure bicyclic 1,2-oxazine derivatives bearing p-bromophenyl substituents, with alkynes. Subsequent hydrogenolyses or a combination of hydrogenolysis and samarium diiodide mediated reductions converted the coupling products into new unnatural amino carbohydrate mimetics with a D-talose configuration. By Glaser coupling reactions we obtained products with a 1,3-diyne linker and divalent compounds derived therefrom. Through Sonogashira reactions of compound 8 with several iodobenzene derivatives, di-, tri-, and tetravalent compounds were prepared in high yields. The subsequent reductive processes converted the 1,2-oxazine moieties into the corresponding aminopyrans. Severe purification problems were solved in most cases by following the appropriate strategies as an apt sequence of steps or by acetylation of the intermediates.