Benzyl tert-but­oxy­carbonyl-α-amino­isobutyrate

The small synthetic peptide, benzyl 2-(tert-but­oxy­carbonyl-amino)­isobutyrate, C₁₆H₂₃NO₄, has the α-helical conformation [|ϕ| = 55.8 (2)° and |ψ| = 37.9 (2)°] observed in peptide fragments of peptaibols containing the α-amino­isobutyric acid (Aib) residue. The structure shows no intramolecular hydrogen bonding, which would disrupt the limited conformational freedom associated with this amino acid. Two weak intermolecular hydrogen contacts are observed.