An efficient and mild protocol for the alpha-arylation of ketones mediated by an (imidazol-2-ylidene)palladium(acetate) system

The activity of well-defined N-heterocyclic carbene (NHC)-palladium acetate complexes has been studied in the alpha-arylation of ketones. The enolate was generated in situ via use of slight excess of sodium tert-butoxide as base. The results showed a high activity, allowing for the coupling of non-activated chlorides. The use of hindered substrates provided an avenue for convenient synthesis of various ketone derivatives. The first examples of alpha-arylation of ketones at room temperature mediated by an NHC-ligated catalyst are also presented. (c) 2005 Elsevier B.V. All rights reserved.