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.