87148-00-3Relevant articles and documents
Palladium-catalyzed diorganozinc conjugate additions to enones: Preparative and computational studies
Lorenzo, Paula,Aurrecoechea, Jose M.,De Lera, Angel R.,Alvarez, Rosana
, p. 2621 - 2626 (2013/06/04)
The Pd-catalyzed conjugate addition of diorganozinc reagents to α,β-unsaturated carbonyl compounds has been applied to a variety of enone substrates, both cyclic and acyclic, encompassing various combinations of aryl and alkyl substitution, in combination with diorganozinc reagents incorporating alkyl (Me, linear and branched) or Ph groups. While both Pd 0 and PdII complexes have been found to be competent precatalysts, reaction yields are strongly dependent on the relative amounts of Pd to phosphane ligand. Thus, a 1:1 Pd/P ratio is well tolerated, but going to Pd/P = 1:2 leads to poor conversions and yields. A calculated Pd 0-mediated pathway involving an unusual oxidative addition step with simultaneous transmetalation, followed by reductive elimination, has been found to be compatible with the observed phosphane effect. A phosphane dependence is found in the Pd0-catalyzed diorganozinc conjugate addition to enones, which is compatible with a calculated reaction pathway proceeding through simultaneous oxidative addition/transmetalation followed by reductive elimination. Copyright
Copper(I) thiolate catalysts in asymmetric conjugate addition reactions
Arink, Anne M.,Braam, Thijs W.,Keeris, Roy,Jastrzebski, Johann T. B. H.,Benhaim, Cyril,Rosset, Stephane,Alexakis, Alexandre,Van Koten, Gerard
, p. 1959 - 1962 (2007/10/03)
Equation presented. Full conversion and enantioselectivities up to 83% have been obtained in the conjugate addition reactions of diethyl zinc to Michael acceptors catalyzed by well-defined (chiral) copper(I) aminoarenethiolates. Interesting differences between organozinc or Grignard reagents have been found: for cyclic enones R2Zn reagents afford better results, whereas earlier work showed that RMgX reagents react more selectively with acyclic enones.
Conjugate addition of diorganozincs to α,β-unsaturated ketones catalyzed by a copper(I)-sulfonamide combined system
Kitamura, Masato,Miki, Takashi,Nakano, Keiji,Noyori, Ryoji
, p. 5141 - 5144 (2007/10/03)
In the presence of a Cu(I)-N-monosubstituted sulfonamide combined catalyst system, diorganozincs react with α,β-unsaturated ketones to generate Zn enolates, which may be hydrolyzed, giving the β-substituted ketones, or used for further aldol reaction or Pd(O)-catalyzed reaction with allyl acetate leading to the regiospecific α,β-vicinal condensation products.
