A resolution of the monodentate P*-chiral phosphine PBu tC 6H 4Br-4 and its NMR-deduced absolute configuration

Abstract

Both enantiomers of the monodentate phosphine PBu t C 6H 4Br-4 were obtained in an enantiopure state by chromatographic separation of their diastereomeric adducts with a new homochiral ortho-palladated resolving agent derived from α- tert-Bu-substituted tertiary benzylamine. The conformation of the palladacycle and the absolute configuration of the phosphine were determined using 1H NMR spectroscopy (including NOE technique) and confirmed by an X-ray diffraction study of both diastereomeric complexes. The enantiomers of the resolved phosphine were displaced from the individual diastereomers of the palladium(II) complexes with recovery of the starting resolving agent, and trapped in the form of binuclear coordination complexes of palladium(II).