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 (IP)Al(THF)Cl [; IP = bis(imino)pyridine; THF = tetrahydrofuran] with the one-electron oxidant (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) afforded (IP)Al(TEMPO)Cl (), which can be reduced with sodium to the twice-reduced ligand complex (IP)Al(TEMPO) (). Compounds and serve as precursors for high-yielding and selective routes to an aluminum-supported 1,3-dihydropyridinate complex via the reaction of with 3 equiv of potassium metal or the reaction of with KH.