The use of chiral transient directing groups (TDGs) is a promising approach for developing Pd^II‐catalyzed enantioselective C(sp³)−H activation reactions. However, this strategy is challenging because the stereogenic center on the TDG is often far from the C−H bond, and both TDG covalently attached to the substrate and free TDG are capable of coordinating to Pd^II centers, which can result in a mixture of reactive complexes. We report a Pd^II‐catalyzed enantioselective β‐C(sp ³)−H arylation reaction of aliphatic ketones using a chiral TDG. A chiral trisubstituted cyclobutane was efficiently synthesized from a mono‐substituted cyclobutane through sequential C−H arylation reactions, thus demonstrating the utility of this method for accessing structurally complex products from simple starting materials. The use of an electron‐deficient pyridone ligand is crucial for the observed enantioselectivity. Interestingly, employing different silver salts can reverse the enantioselectivity.

中文翻译：

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使用手性瞬态定向基团对环丁基酮进行PdII催化的对映选择性C（sp3）-H芳基化反应。

使用手性瞬态导向基团（TDGs）是开发Pd ^II催化的对映选择性C（sp ³）-H活化反应的一种有前途的方法。但是，此策略具有挑战性，因为TDG上的立体中心通常距离C H键很远，并且共价连接到底物上的TDG和游离TDG都能够与Pd ^II中心配位，这可能导致反应性配合物。我们报告了P​​d ^II催化的对映选择性β-C（sp ³使用手性TDG的脂肪族酮的）-H芳基化反应。通过顺序的CH芳基化反应，从单取代的环丁烷有效地合成了手性三取代的环丁烷，从而证明了该方法可用于从简单的起始原料获得结构复杂的产物。缺电子的吡啶酮配体的使用对于观察到的对映选择性至关重要。有趣的是，采用不同的银盐可以逆转对映选择性。