Enantioface-Selective Coordination of Prochiral 1,3-Dienes to Planar-Chiral Cyclopentadienyl-Ruthenium Complexes MatsushimaYuji OnitsukaKiyotaka TakahashiShigetoshi 2004 The treatment of planar-chiral (η<sup>5</sup>:η<sup>1</sup>-cyclopentadienylphosphine)bis(acetonitrile)ruthenium complexes <b>1</b> with prochiral dienes led to the ligand-exchange reaction that gave (η<sup>5</sup>:η<sup>1</sup>-cyclopentadienylphosphine)(η<sup>4</sup>-diene)ruthenium complexes <b>4</b>−<b>6</b> and <b>8</b>−<b>11</b> with high enantioface selectivity (up to >99% de). The configuration of the (η<sup>4</sup>-diene)ruthenium complexes was determined by crystallographic study of (η<sup>4</sup>-isoprene)ruthenium complex <b>6b</b><b>-</b><b>I</b> and spectral analyses, including NOE measurements. The selectivity of the reaction is under thermodynamic control of the resulting η<sup>4</sup>-diene complexes and is affected by the substituents on both the cyclopentadienyl ligand and the diene.