Synthesis of (R)-(+)-Boc-Iturinic Acid (n-C₁₄) from Aspartic Acid

Abstract

The first enantiospecific synthesis of the n-C₁₄ isomer of iturinic acid, suitably protected for peptide synthesis, is presented. A new method for the synthesis of enantiomerically pure β-amino acids from aspartic acid is used. The key step consists of an organocuprate addition to a tosylate derivative of aspartic acid, reduced at the α-carboxylic acid.