Total synthesis of the biphenomycins; III. Synthesis of biphenomycin B

Article abstract of DOI:10.1055/s-1992-26293

The total synthesis of the cyclopeptide biphenomycin B (1b), a compound exhibiting a potent antibacterial activity against Gram-positive bacteria, is described. The non-proteinogenic amino acid (S,S)-diisotyrosine (2) was prepared by enantioselective hydrogenation of the corresponding didehydroamino acids. The 15-membered ansa ring was obtained in 85% yield within 5 minutes by ring closure of the appropriate linear pentafluorophenyl ester in the two phase system chloroform-aqueous sodium hydrogen carbonate without dilution.