III International Conference

Ru(III)-BASED HOMOGENEOUS CATALYTIC SYSTEM FORENANTIOSELECTIVE HYDROGENATION OF C=O BONDPP-I-54Turova O.V., Starodubtseva E.V., Vinogradov M.G., Ferapontov V.A.N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, RussiaE-mail: ving@ioc.ac.ruRuthenium catalysts (P*P)RuCl 2 (P*P is chiral bisphosphine ligand) for homogeneousasymmetric hydrogenation reactions are traditionally prepared from RuCl 3 , most accessibleruthenium starting reagent, by means of its transforming into intermediate complexes such as[(COD)RuCl 2 ] n or (COD)Ru(2-methylallyl) 2 with subsequent replacement of COD(cycloocta-1,5-diene) ligand by chiral bisphosphine. We report now about using of newcatalytic system: RuCl 3 –BINAP–HCl [BINAP is (R)- or (S)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl] for asymmetric hydrogenation of C=O bond This system proved to be highlycompetitive by its activity and enantioselectivity with similar Ru(II)-based catalytic systems,but for all that no intermediate π-olefine or allyl ruthenium complexes are reguired to preparebefore. Using the new Ru(III)-based system for asymmetric catalytic hydrogenation of anumber of ketoesters R-C(O)-CH 2 CH 2 COOMe (R = Me, Et, Pr, iso-Pr, Ph) has beenperfomed to give chiral γ-hydroxyesters. In the course of hydrogenation ([ketoester]:[HCl]:[Ru]:[BINAP] = 200:5:1:1, MeOH, p(H 2 ) = 15-60 atm, 65 o C, 6 h) hydroxyesters arecyclized into γ-alkylbutyrolactones characterized by high optical purity (up to 99 % ee). Theresults obtained open up possibilities to realize scaled-up process of enantioselectivehydrogenation of γ-ketoesters taking into consideration that chiral γ-alkylsubstitutedbutyrolactones are valuable building blocks for pharmaceutical goals.103