Ferrocene-derived bioorganometallic chemistry:: Preparation of a [3]ferrocenophane γ-amino acid for use in peptide synthesis

Directed lithiation followed by quenching with CO2 converted the alpha-dimethylamino[3]ferrocenophane derivative (6R,9R)-1 to the corresponding acid derivative (6R,9R,pR)-2. Subsequent functional group interconversion steps gave (6R, 9R,pR)-6 in an overall yield of ca. 40% (four steps from (6R,9R)-1), which was employed in the synthesis of an artificial model pentapeptide.