Catalytic borylations of sp³ C–H bonds occur with high selectivities for primary C–H bonds or secondary C–H bonds that are activated by nearby electron-withdrawing substituents. Catalytic borylation at tertiary C–H bonds has not been observed. Here we describe a broadly applicable method for the synthesis of boron-substituted bicyclo[1.1.1]pentanes and (hetero)bicyclo[2.1.1]hexanes by an iridium-catalysed borylation of the bridgehead tertiary C–H bond. This reaction is highly selective for the formation of bridgehead boronic esters and is compatible with a broad range of functional groups (>35 examples). The method is applicable to the late-stage modification of pharmaceuticals containing this substructure and the synthesis of novel bicyclic building blocks. Kinetic and computational studies suggest that C–H bond cleavage occurs with a modest barrier and that the turnover-limiting step of this reaction is an isomerization that occurs prior to reductive elimination that forms the C–B bond.

sp ³ C-H 键的催化硼化反应对被附近吸电子取代基激活的伯 C-H 键或仲 C-H 键具有高选择性。尚未观察到叔 C-H 键的催化硼化作用。在这里，我们描述了一种广泛适用的方法，通过桥头叔 C-H 键的铱催化硼基化来合成硼取代的双环[1.1.1]戊烷和（杂）双环[2.1.1]己烷。该反应对于桥头硼酸酯的形成具有高度选择性，并且与多种官能团兼容（> 35 个实例）。该方法适用于含有该子结构的药物的后期修饰以及新型双环结构单元的合成。动力学和计算研究表明，C-H 键断裂在适度的势垒下发生，并且该反应的周转限制步骤是在形成 C-B 键的还原消除之前发生的异构化。