Ir-catalyzed highly selective addition of pyridyl C–H bonds to aldehydes promoted by triethylsilane

We report herein an iridium-catalyzed activation of pyridine C–H bond and its nucleophilic addition to benzaldehydes. The reaction was applicable to various pyridine derivatives and aryl aldehydes. In contrast to most methods that selectively functionalize the C2 pyridine C–H bond, this reaction proceeded with unusual meta-selectivity. An independently synthesized silyl iridium complex was able to catalyze the reaction, indicating that a silyl iridium intermediate might be responsible for the novel reactivity and the unusual selectivity.