142809-74-3Relevant articles and documents
Chiral phosphanylferrocenecarboxamides with amino acid pendant groups as ligands for Cu-mediated asymmetric conjugate additions of diethylzinc to chalcones - Structural characterisation of precursors to the Cu catalyst
Tauchman, Jiri,Cisarova, Ivana,Stepnicka, Petr
experimental part, p. 4276 - 4287 (2010/10/21)
A series of chiral phosphanylferrocenecarboxamides was prepared by treatment of either l'-(diphenylphosphanyl)ferrocene-1-carboxylic acid (Hdpf) or its planar-chiral 1,2isomers with amino acid methyl esters in the presence of peptide coupling agents. The compounds were characterised by spectroscopic methods, and the crystal structure of one representative was determined by X-ray diffraction. Catalytic testing of these donors in Cu-catalysed asymmetric conjugate additions of diethylzinc to chalcones revealed that the reaction outcomes were highly sensitive to the ligand structure and the reaction conditions (copper source and solvent), whereas the chalcone substituents (Me, MeO, or Cl in positions 4 or 4') had a less pronounced influence. Compounds based on Hdpf proved to be better ligands than their planarchiral analogues. Under optimised conditions, the reaction with L-valine-Hdpf conjugate, (S)-Ph2PfcCONHCH(CHMe2)CO2Me (fc = ferrocene-1,1'-diyl) and unsubstituted chalcone gave the alkylation product with complete conversion (20 °C/ 4 h) and in 87 % ee. The catalytic behaviour of the amidophosphane ligands was correlated to the results of a model coordination study and the crystal structure of [Cu(Ph2PfcCONHCH 2CO2Me)2](CF3SO3) ·2CHCl3.
Enantioselective Conjugate Addition of Diethylzinc to Chalcones Using NiCl2-Chiral β-Diamine Complex as Catalyst
Asami, Masatoshi,Usui, Kenji,Higuchi, Sohmei,Inoue, Seiichi
, p. 297 - 298 (2007/10/02)
A chiral catalyst prepared from nickel(II) chloride and chiral β-diamine, (S)-1-pentyl-2-anilinomethylpyrrolidine, was found to be effective for the enantioselective conjugate addition of diethylzinc to chalcones to afford corresponding β-substituted keto