SYNTHESIS, STRUCTURE, AND CHARACTERIZATION OF CHIRAL RU(II) AMINOPHOSPHINE PHOSPHINITE COMPLEXES AND THEIR APPLICATION IN ASYMMETRIC HYDROGENATION OF ALPHA-FUNCTIONALIZED KETONES - X-RAY CRYSTAL-STRUCTURE OF RU((S)-PH,PH-PRONOP)(2-METHYLALLYL)(2)

Reactions of the ruthenium(ll) precursors [RUCl2(C6H6)](2) and [Rul(2) (p-cymene)](2) with the aminophosphine phosphinite ligands (AMPP) (S)- Cy,Cy-ProNOP and (S)-Ph,Ph-ProNOP gave the cationic complexes [RuCl(C6 H6){(S)-Cy,Cy-ProNoP}]Cl 1, [RuCl(C6H6){(S)-Ph, PhProNOP}]Cl 2, and [R ul(p-cymene){(S)-Ph, Ph-ProNOP}]l 3 in good to high yields. The reacti ons proceed in two steps via a monodentate intermediate in which the P O moiety of the AMPP diphosphine coordinates to the ruthenium prior to the chelation through PN coordination, giving the expected bidentate complexes. Neutral complexes have been synthesized starting from the R u(COD)(2-methylallyl)(2) precursor. Accordingly, complexes Ru{(S)-Ph,P h-ProNOP}(2-methylallyl)(2) 4 and Ru{(S)-Ph,Ph-oxoProNOP}(2-methylally l)(2) 5 are obtained through reaction with (S)-Ph,Ph-ProNOP and (S)-Ph ,Ph-oxoProNOP, respectively, by progressive precipitation in the react ion mixtures. X-ray data are given for the neutral methylallyl complex Ru{(S)-Ph,Ph-ProNOP}(2-methylallyl)(2) 4. Complexes Ru{(S)-Cy,Cy-ProN OP}(OCOCH3)(2) 6 and Ru{(S)-Cy,Cy-ProNOP}(OCOCF3)(2) 7 were obtained t hrough substitution of the COD ligand in Ru(COD)(OCOCH3)(2) and Ru-2(C OD)(2)(OCOCF3)(4), respectively. Neutral acetato and trifluoroacetato complexes Ru{(S)-Ph,Ph-ProNOP}(OCOCH3)(2) 8, Ru{(S)Ph,Ph-oxoProNOP}(OC OCH3)(2) 9, Ru{(S)-Ph,Ph-ProNOP}(OCOCF3)(2) 10, and Ru{(S)-Ph,Ph-oxoPr oNOP}(OCOCF3)(2) 11 were synthesized through protonation of the corres ponding methylallyl ruthenium complexes with the appropriate hydracid. All the catalyst precursors synthesized are mixtures of diastereoisom ers and have been applied in asymmetric hydrogenation of three or-func tionalized ketones, i.e., dihydro-2,4-dimethyl-2,3-furandione 12, ethy lpyruvate 13, and methylbenzoylformate 14. Enantiomeric excesses (ee) up to 79.5, 63, and 48% were obtained, respectively, for the three sub strates.