Deprotonative formation of biarylazacyclooctynone (BARAC) from the corresponding enol triflate is described. The reaction furnished the azacyclooctynone within one hour at –78 °C. This process could be performed in one pot from the starting ketone to provide a range of BARAC derivatives in moderate to excellent yields. The protocol enabled the gram-scale formation of the BARAC skeleton by reducing the number of reaction steps. Furthermore, the established method was applied to the synthesis of the BARAC derivative bearing a coumarin moiety.
描述了从相应的烯醇三氟甲烷磺酰基形成双芳基氮杂环辛酮(BARAC)的去质子化反应。该反应在-78℃下在一个小时内生成了氮杂环辛酮。该过程可以在同一反应釜中完成,从起始酮提供一系列BARAC衍生物,收率从中等到优良。该方案通过减少反应步骤,实现了克级别的BARAC骨架形成。此外,该方法已应用于合成带有香豆素基团的BARAC衍生物。