Chiral Bis(oxazoline) Ligands as C-2-Symmetric Chiral Auxiliaries for the Synthesis of Enantiomerically Pure Bis-Cyclometalated Rhodium(III) Complexes

摘要

The synthesis of enantiomerically pure bis-cyclometalated rhodium(III) complexes using chiral bis(oxazoline) ligands as C-2-symmetric chiral auxiliaries is described. Bis(oxazolines) are versatile chiral ligands for asymmetric catalysis but have not been applied to the resolution of racemic mixtures of transition-metal complexes. Due to their C-2 symmetry, chiral bis(oxazolines) are particularly useful for the synthesis of nonracemic transition-metal complexes with lower symmetry, and this is demonstrated with the synthesis of an enantiomerically pure rhodium(III) complex containing two different cyclometalated ligands.