Atropisomeric N‐Heterocyclic Carbene‐Palladium(II) Complexes: Influence of the Backbone Substitution

Abstract

AbstractIn order to facilitate the synthesis of NHC precursors as well as to incorporate new moieties, the influence of the NHC backbone substitution was investigated within the concept of atropisomeric NHC‐metal complexes. A series of NHC precursors was prepared from new anilines and used to synthesize the corresponding Pd(allyl)Cl(NHC) complexes, most of the time as a mixture of diastereomers (meso and chiral). Chiral HPLC at preparative scale enabled to obtain enantiopure complexes in low to excellent yields. These complexes displayed good activity in the intramolecular α‐arylation of amides and, as a function of the structure of the chiral catalyst, excellent enantioselectivities were reached (up to 96 % ee).