RESUMO
The synthesis, characterization, and catalytic performance of an iridium(III) catalyst with an electron-deficient cyclopentadienyl ligand ([CpE IrI2 ]2 ) are reported. The [CpE IrI2 ]2 catalyst was synthesized by complexation of a precursor of the CpE ligand with [Ir(cod)OAc]2 , followed by oxidation, desilylation, and removal of the COD ligand. The electron-deficient [CpE IrI2 ]2 catalyst enabled C-H amidation reactions assisted by a weakly coordinating ether directing group. Experimental mechanistic studies and DFT calculations suggested that the high catalytic performance of [CpE IrI2 ]2 is due to its electron-deficient nature, which accelerates both C-H activation and IrV -nitrenoid formation.
RESUMO
The synthesis, characterization, and catalytic performance of iridium(III) catalysts that bear an amide-pendant cyclopentadienyl ligand ([CpA IrI2 ]2 ) is reported. These [CpA IrI2 ]2 catalysts were obtained from the complexation of a CpA ligand precursor with [Ir(cod)OAc]2 followed by oxidation. Double aromatic homologation reactions of benzamides with alkynes by fourfold C-H activation proceeded in good to high yield with these [CpA IrI2 ]2 catalysts, demonstrating their superior catalytic performance in this challenging transformation.
RESUMO
Reported is an achiral Cpx RhIII /chiral carboxylic acid catalyzed asymmetric C-H alkylation of diarylmethanamines with a diazomalonate, followed by cyclization and decarboxylation to afford 1,4-dihydroisoquinolin-3(2H)-one. Secondary alkylamines as well as nonprotected primary alkylamines underwent the transformation with high enantioselectivities (up to 98.5:1.5 e.r.) by using a newly developed chiral carboxylic acid as the sole source of chirality to achieve enantioselective C-H cleavage by a concerted metalation-deprotonation mechanism.
