1.
J Org Chem
; 85(22): 14730-14743, 2020 11 20.
Artigo
em Inglês
| MEDLINE
| ID: mdl-33166470
RESUMO
We report herein an efficient synthesis of diversely polysubstituted imidazo[1,2-a]pyridines, a family of aza-heterocycles endowed with numerous biological properties, through a sequence involving two consecutive palladium-catalyzed cross-coupling reactions. First, we demonstrated that a Hirao coupling occurred straightforwardly in high yields at positions 3, 5, and 6 of imidazopyridine derivatives, giving access to a wide variety of substituted phosphonates, phosphinates, and phosphine oxides. In a second step, direct CH-arylation of phosphorylimidazopyridines with aryl halides was found to be effective and fully selective, leading to 3-aryl-substituted imidazopyridines in moderate to high yields depending on steric hindrance.