Cyclic (alkyl)(amino)carbenes with a six-membered backbone were prepared. Compared to their five-membered analogues, they feature increased % Vbur and enhanced donor and acceptor properties, as evidenced by the observed n → π* transition trailing into the visible region. The high ambiphilic character even allows for the intramolecular insertion of the carbene into an unactivated C(sp3)-H bond. When used as ligands, they outcompete the five-membered analogues in the palladium-mediated α-arylation of ketones with aryl chlorides.

中文翻译：

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高度两亲性室温稳定的六元环（烷基）（氨基）卡宾

制备了具有六元骨架的环状（烷基）（氨基）卡宾。与其五元类似物相比，它们具有增加的 Vbur 百分比和增强的供体和受体特性，正如观察到的 n → π* 跃迁尾随进入可见光区所证明的那样。高度的两亲性甚至允许将卡宾分子内插入到未活化的 C(sp3)-H 键中。当用作配体时，它们在钯介导的酮与芳基氯的 α-芳基化中胜过五元类似物。