Chiral Phosphinopyrrolyl-Oxazolines: A New Class of Easily Prepared, Modular P,N-Ligands

Abstract

Chiral 2-(N-phosphinopyrrol-2-2)oxazolines (PyrPHOX ligands) are readily prepared from 2-cyanopyrrole by condensation with a chiral amino alcohol and subsequent reaction with dialkyl- or diaryl-chlorophosphines. Iridium complexes of these ligands proved to be highly efficient catalysts for the enantioselective hydrogenation of olefins. With unfunctionalized arylalkenes and ethyl cinnamate enantiomeric excesses of 70–99% were obtained.