Enantioface-Selective Coordination of Prochiral 1,3-Dienes to Planar-Chiral Cyclopentadienyl-Ruthenium Complexes

The treatment of planar-chiral (η⁵:η¹-cyclopentadienylphosphine)bis(acetonitrile)ruthenium complexes 1 with prochiral dienes led to the ligand-exchange reaction that gave (η⁵:η¹-cyclopentadienylphosphine)(η⁴-diene)ruthenium complexes 4−6 and 8−11 with high enantioface selectivity (up to >99% de). The configuration of the (η⁴-diene)ruthenium complexes was determined by crystallographic study of (η⁴-isoprene)ruthenium complex 6b-I and spectral analyses, including NOE measurements. The selectivity of the reaction is under thermodynamic control of the resulting η⁴-diene complexes and is affected by the substituents on both the cyclopentadienyl ligand and the diene.