Asymmetric Kumada–Tamao–Corriu Cross-Coupling Catalyzed by Chiral Pd(NHC) Complexes

Abstract The Kumada–Tamao–Corriu cross-coupling reaction affording axially chiral biaryl compounds has been investigated with various chiral Pd(NHC) complexes (NHC = N-heterocyclic carbene). While the nature of the aryl halide partner did not have an influence on the enantioselectivity, the enantioenrichment of coupling products was found to be highly dependent on the structure of the arylmagnesium halide, and also on the chiral Pd(NHC) complex used. Thus, up to 63% ee was achieved using an atropisomeric Pd(NHC) complex. These data, along with role-reversal experiments of cross-coupling partners, suggest that the reductive elimination step is likely to be rate- and enantio-determining.