Alkali Metal Dihydropyridinates: From Hidden Intermediates to Promising Well-defined Catalysts?

Often the synthesis of catalysts can be time-consuming, multistep tasks, but sometimes they can turn up fortuitously, hidden treasure finds in essence. The alkali metal dihydropyridinate complexes discussed here fit the latter scenario. First reported simply as in situ intermediates by reaction of two commercially available reagents, an alkyllithium and pyridine, a whole class of such compounds, isolated and structurally characterised are now known where M = Li, Na, K, Rb and Cs. Here, some of their recent applications in homogeneous catalysis are outlined, including dehydrocoupling of aminoboranes, hydroboration of aldehydes and ketones, dehydrocyclization of diamine boranes, and transfer hydrogenation of alkenes to alkanes.