Synthesis and application of chiral phosphino-imidazoline ligands: Ir-catalyzed enantioselective hydrogenation.
[reaction: see text] A series of chiral phosphino-imidazolines (PHIM ligands) 1a-j with different substituents at the stereogenic center, the nitrogen atom of the imidazoline ring, and at the phosphorus atom were synthesized. Iridium complexes derived from these ligands have been evaluated as catalysts for the enantioselective hydrogenation of unfunctionalized olefins. In several cases, higher enantiomeric excesses were observed than with analogous phosphino-oxazoline ligands.
Menges
Frederik
F
Department of Chemistry, University of Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland.
Neuburger
Markus
M
Pfaltz
Andreas
A