Carbonylative Tertiary Amide Synthesis from Aryl Iodides and Tertiary Amines via Oxidant-Free C-N Bond Cleavage Catalyzed by Palladium(II) Chloride in Polyethylene Glycol/Water

In this work, we have described the carbonylative synthesis of amides from aryl iodides and tertiary amines as an aminal source via oxidant-free C(sp(3))-N bond cleavage using in situ formation of palladium(0) nanoparticles from palladium(II) chloride in polyethylene glycol 400/water. Notably, these reactions were performed under base-free, ligand-free conditions and do not require any oxidant for the C-N bond cleavage. The developed protocol offers the selective N-dealkylation of tertiary amines in a polyethylene glycol/water solvent system. Numerous symmetrical and unsymmetrical aliphatic, alicyclic, benzyl, as well as aromatic tertiary amines with aryl iodides were well tolerated and afforded the desired products in good yields. Furthermore, the in situ generation of palladium(0) nanoparticles in the polyethylene glycol 400 was confirmed by TEM, FEG-SEM, EDS and XRD techniques, which strongly indicate that the palladium nanoparticles are highly active species and the reaction proceeds through the classical palladium(0)/palladium(II) pathway. Additionally, the syntheses can be easily scaled up and the catalytic system can be recycled up to five times without loss of its catalytic activity and selectivity.