Synthesis of Aza-Surfactin and 3-Epi-Aza-Surfactin

Abstract

Two synthetic approaches to aza-surfactins are reported. In the first, our recently developed synthesis of unnatural ! 3 -amino acids was used to prepare the requisite monomer, which was used in solid phase peptide synthesis, and followed by macrolactamization of a partially protected precursor. In the second, the corresponding ! 3 -N-hydroxyaminoacid was used to prepare a fully unprotected cyclization precursor that was closed to give 3-epi-aza-surfactin by the first example of cyclization by the "-ketoacid-hydroxylamine amide formation.