DFT Studies on the Palladium-Catalyzed Dearomatization Reaction between Chloromethylnaphthalene and the Cyclic Amine Morpholine

Density functional theory calculations have been performed to investigate the mechanisms of the Pd-catalyzed dearomatization reaction between chloromethylnaphthalene and the cyclic amine morpholine. The calculation results indicate that the reductive elimination leading to the formation of the dearomatic product takes place via an intramolecular C-N bond coupling between the para carbon of an eta(3)-exo-(naphthyl)methyl ligand and the nitrogen atom of the amide ligand. The free energy barrier is calculated to be only 13.1 kcal/mol, significantly lower than that (37.8 kcal/mol) through the eta(3)-endo-(naphthyl)methyl intermediate originally thought For comparison, various C-N coupling reaction pathways leading to the formation of dearomatic and aromatic products have also been examined.