Total synthesis of (+)-conagenin

Article abstract of DOI:10.1016/0040-4039(96)00758-7

The first total synthesis of (+)-conagenin, a novel immunomodulator produced by Streptomyces roseosporus, has been achieved in highly stereo- and enantioselective manner. The carboxylic acid moiety was synthesized starting with asymmetric aldor reaction of propiophenone with acetaldehyde followed by in situ syn-selective NaBH₄ reduction. The amin acid moiety was synthesized based upon Et₂AlCl catalyzed cyclization of the epoxy trichloroacetimidate prepared from (S)-methylglycidol. Condensation of both moieties and alkaline hydrolysis led to (+)-conagenin.