Nitroacetyl Group as a Peptide Synthon: Synthesis of Dipeptides with an α,α‐Bisallylglycine Residue at the N‐Terminus

Abstract

N‐Nitroacetyl derivatives of L‐proline, L‐valine, and L‐phenylalanine esters were prepared in two steps under mild conditions (Scheme 2). Regiospecific mono‐ and bis‐allylation of these nitroacetyl derivatives were accomplished in presence of a Pd(0) catalyst. The bis‐allyl derivatives 7–9 were obtained in 40–75% yield. The tertiary NO₂ group in these compounds could be transformed into an acetylamino group by Zn/AcOH/Ac₂O. The final products 11–13 are dipeptides in which the N‐terminal glycine residue bears two α‐allyl substituents.