The synthesis of complex C-glycoconjugates is presented here using a key directed nickel-catalyzed C−H alkynylation step. Thanks to a bidentate amidoquinoline-type directing group, the insertion of diverse alkynyl moieties onto the pseudo-anomeric position of glycal substrates was performed on ten examples in moderate to good yields. These platforms were used as starting substrates in a click reaction with complex azides to form original C-glycoconjugates. By this route, a C-glycosylated amino acid, a C-linked disaccharide and a C-glycosylated biotin derivative were synthesized. Preliminary conditions to remove the directing group are also proposed.

中文翻译：

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糖基化的定向镍催化假异头 C-H 炔基化作为 C-糖缀合物合成的一种方法

此处介绍了使用关键的镍催化 C-H 炔基化步骤合成复杂的C-糖缀合物。由于双齿酰氨基喹啉型导向基团，在十个实例中以中等至良好的产率将不同的炔基部分插入到糖基底物的假异头位置上。这些平台在与复合叠氮化物的点击反应中用作起始底物，以形成原始的C-糖缀合物。通过该途径，合成了C-糖基化氨基酸、C-联二糖和C-糖基化生物素衍生物。还提出了去除指导组的初步条件。