Total synthesis of geralcin A, a representative of a new family of hydrazine-containing natural products

The first total synthesis of geralcin A (2), a naturally occurring α,β-unsaturated γ-lactonohydrazide produced by Streptomyces sp. LMA-545, was achieved according to the hypothetical biosynthesis we have previously published. MH-031 (1), the plausible natural precursor isolated together with geralcin A, was synthesized in 6 steps and in a 25% overall yield. Condensation of glycolic acid with key intermediate Boc-hexylhydrazine afforded the desired geralcin A in 46% overall yield. Spectroscopic data of the synthetic compound were identical to those recorded for the natural one.