Synthesis, characterization, diastereoselectivity, and catalytic activity of complexes of ruthenium with BINAP monoxide

The bisphosphine monoxides (R)- and (S)-BINPO, prepared by the monoxidation of (R)- and (S)-BINAP, respectively, form complexes [CyRuCl(eta(2)-BINPO-P)]X (X = Cl-, (R)-BINPO, 1, (S)-BINPO, 1'; or SbF6-, 2 and 2') and [CyRu(eta(2)-BINPO-P, O)](SbF6)(2), 3 and 3'. The new compounds were characterized spectroscopically and in the case of 2' by single-crystal X-ray diffraction. The BINPO ligand binds diastereoselectively, and one observes only a single thermodynamically stable diastereomer of the two possible isomers. Compound 3 is an efficient catalyst for the condensation of methacrolein and cyclopentadiene in moderate ee.