SYNTHESES TOTALES ET ETUDES DE LIGNANES BIOLOGIQUEMENT ACTIFS-I. APPLICATION DE LA REACTION D'ULLMANN A LA SYNTHESE DE BIARYLES PRECURSEURS DE LIGNANES BISBENZOCYCLOOCTADIENES
Several biaryls bearing various substituents on both rings were synthesized in a preparativ fashion, and in yields up to 88percent by a technical improvement on the classical Ullmann reaction.All these biaryls bear reactive functional groups (i.e. formyl, methoxycarbonyl, dimethoxycarbonylpropyl and butanolidylmethyl) in both the o and o' positions.The biaryls 9, 13, 21 and 26-33 are plausible synthons for bisbenzocyclooctadiene lignans such as schizandrin and steganacin.
Brown, Eric,Robin, Jean-Pierre,Dhal, Robert
p. 2569 - 2580
(2007/10/02)
The Ambient Temperature Ullmann Reaction and Its Application to the Total Synthesis of (+/-)-Steganacin
The details of a new method for preparing unsymmetrical biphenyls at room temperature by a modification of the classical Ullmann reaction are discussed.An intramolecularly coordinated organocopper reagent is treated with an aryl iodide bearing a potential coordinating ligand to form the biphenyl.Nitrogen and sulfur have been utilized as ligands and as protecting groups for carbonyls.The application of this methodology to the synthesis of the antileukemic steganacin is detailed.
Ziegler, Frederick E.,Chliwner, Irene,Fowler, Kerry W.,Kanfer, Sheldon J.,Kuo, Stephen J.,Sinha, Nanda D.
p. 790 - 798
(2007/10/02)
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