Stereoselective Synthesis of an Immunomodulator (+)-Conagenin Using Dirhodium(II)-Catalyzed C-H Amination and Chelation-Controlled Reductions as Key Steps
Stereoselective synthesis of an immunomodulator (+)-conagenin was achieved. Both amine and carboxylic acid moieties were prepared from commercially available optically active methyl 3-hydroxy-2-methylpropanoate using dirhodium(II)-catalyzed C–H amination and chelation-controlled reductions as key steps. In addition, demethyl analogs of conagenin were synthesized using similar procedures.
An efficient synthesis of (+)-conagenin, a novel immunomodulator produced by Streptomyces roseosporus, has been achieved via the shortest route at present. At the same time, 2-epiconagenin was synthesized according to the same methodology. (C) 2008 Elsevier Ltd. All rights reserved.