Inorganic Chemistry, Vol.59, No.23, 17614-17619, 2020
Ligand Conjugation Directs the Formation of a 1,3-Dihydropyridinate Regioisomer
The selective formation of the 1,4-dihydropyridine isomer of NAD(P)H is mirrored by the selective formation of 1,4-dihydropyridinate ligand-metal complexes in synthetic systems. Here we demonstrate that ligand conjugation can be used to promote selective 1,3-dihydropyridinate formation. This represents an advance toward controlling and tuning the selectivity in dihydropyridinate formation chemistry. The reaction of (I2P2-)Al-(THF)Cl [1; I2P = bis(imino)pyridine; THE = tetrahydrofuran] with the one-electron oxidant (2,2,6,6-tetramethylpiperidin-l-yl)oxyl (TEMPO) afforded (I2P-)Al(TEMPO)Cl (2), which can be reduced with sodium to the twice-reduced ligand complex (I2P2-)Al(TEMPO) (3). Compounds 2 and 3 serve as precursors for high-yielding and selective routes to an aluminum-supported 1,3-dihydropyridinate complex via the reaction of 2 with 3 equiv of potassium metal or the reaction of 3 with KH.