Direct Addition of Amides to Glycals Enabled by Solvation‐Insusceptible 2‐Haloazolium Salt Catalysis
作者:Yuya Nakatsuji、Yusuke Kobayashi、Yoshiji Takemoto
DOI:10.1002/anie.201907129
日期:2019.10
The direct 2-deoxyglycosylation of nucleophiles with glycals leads to biologically and pharmacologically important 2-deoxysugar compounds. Although the direct addition of hydroxyl and sulfonamide groups have been well developed, the direct 2-deoxyglycosylation of amide groups has not been reported to date. Herein, we show the first direct 2-deoxyglycosylation of amide groups using a newly designed
亲核试剂与糖的直接2-脱氧糖基化会导致生物学上和药理上重要的2-deoxysugar化合物。尽管已经很好地开发了羟基和磺酰胺基团的直接加成,但是迄今为止尚未报道酰胺基团的直接2-脱氧糖基化。在这里,我们显示了使用新设计的布朗斯台德酸催化剂在温和条件下的酰胺基团的直接直接2-脱氧糖基化。通过机理研究,我们发现酰胺基团可以抑制酸催化剂,并且该抑制作用使得2-脱氧糖基化反应变得困难。扩散排序的二维NMR光谱分析表明,与其他酸催化剂相比,2-氯偶氮盐催化剂不太可能与酰胺形成聚集体。氯原子和催化剂的扩展π骨架对这一现象起着至关重要的作用。酰胺抑制作用的这种相对不敏感性比酸度的强度更负责催化活性。