Theoretical studies on β-aryl elimination from Rh(i) complexes

Abstract

β-Aryl eliminations in a series of rhodium alkoxide, alkyl and amido complexes were investigated with the aid of density function theory calculations at the Becke3LYP level. Our calculation results indicate that the typical barriers for β-aryl eliminations are in the range of 20–25 kcal mol⁻¹. For comparison, β-allyl and β-vinyl eliminations were also studied. It was found that β-allyl elimination is noticeably more favourable than β-aryl elimination while β-vinyl elimination is only slightly more favourable. The reversible reactions of β-aryl elimination correspond to the insertion reactions into a metal–aryl bond. On the basis of the thermochemistry calculated, we discussed the factors influencing the thermodynamic preference of the β-aryl elimination vs.insertion (the reversible process). The results indicate that the preference can be switched when different substrates and ligands are used.