Palladium‐catalyzed site‐selective C7 oxidative arylation of 4‐EWG‐1 H ‐Indazoles
Résumé
An efficient palladium‐catalyzed oxidative arylation of substituted 1$H$‐indazole with various arenes and heteroarenes as coupling partners is reported. A site selective C7 oxidative arylation was perfectly achieved with a directing electron‐withdrawing groups (EWG) located at the C4 position of the 1$H$‐indazole. The desired products are obtained in moderate to good yields from 4‐NO$_2$ or 4‐CO$_2$ Me 1$H$‐indazoles and various (hetero)aryls as coupling partners in the presence of Pd(OAc)$_2$ as catalyst, phenanthroline as ligand, Ag$_2$ CO$_3$ as oxidant and NaOH as the base. Density functional theory was also conducted for reaction mechanism comprehension. This approach provides a highly effective, direct, and atom economical way to build C7‐ (het)arylated 1$H$‐indazole compounds.
Domaines
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