258. E. Raluy, O. Pàmies, M. Diéguez, S. Rosset, A. Alexakis,
     “Furanoside phosphite-phosphoroamidite and diphosphoroamidite ligands for Cu-catalyzed asymmetric 1,4-addition reactions”
     Tetrahedron: Asymmetry 2009, 20, 1930-1935.

A sugar-based phosphite–phosphoroamidite and diphosphoroamidite ligand libraryL1–L5a–g was tested in the asymmetric Cu-catalyzed 1,4-conjugate addition reactions of β-substituted and β,β′-disubstituted enones. Our results indicated that the selectivity was strongly dependent on the ligand parameters and on the substrate structure. Moderate-to-good enantioselectivities (ees up to 84%) were obtained in the 1,4-addition of several types of β-substituted cyclic and linear substrates. Of particular note is the high enantioselectivity (ees up to 90%) obtained for the more challenging β,β′-disubstituted 3-methyl-cyclohexenone.

DOI : 10.1016/j.tetasy.2009.07.018 

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