Theoretical Study on the Mechanism of Palladium-Catalyzed Dearomatization Reaction of Chloromethylnaphthalene

The Pd-catalyzed dearomatization of chloromethylnaphthalene with allenyltributylstannane has been investigated at the B3LYP density functional level of theory. The calculations indicate that the monophosphine complex is catalytically more active than the bisphosphine complex for oxidative addition. The transmetalation step is a crucial step for determining the dearomatized products due to the formation of two stable bis-pi-complexes. It is found that reductive elimination occurs by coupling the terminal carbons of the eta(1)-propargyl ligand and if-allenyl ligand with the para-carbons of the eta(3)-methylnaphthalene ligands in eta(3)-methylnaphthalene-eta(1)-propargyl-Pd(PH3) and eta(3)-methylnaphthalene-eta(1)-allenyl-Pd(PH3) to form the corresponding allenylated and propargylated dearomatization products. For comparison, various C-C coupling pathways in reductive elimination have also been studied.