Crystal structure of Boc-(S)-ABOC-(S)-Ala-(S)-ABOC-(S)-Phe-OBn chloro­form monosolvate

In the title compound, phenyl (S)-2-[(S)-(1-{2-[(S)-(1-{[(tert-but­oxy)carbon­yl]amino}­bicyclo­[2.2.2]octan-2-yl)formamido]­propanamido}­bicyclo­[2.2.2]octan-2-yl)formamido]-3-phenyl­propano­ate chloro­form monosolvate, C(42)H(56)N(4)O(7)·CHCl(3), the α,β-hybrid peptide contains two non-proteinogenic amino acid residues of (S)-1-amino­bicyclo­[2.2.2]octane-2-carb­oxy­lic acid [(S)-ABOC], two amino acid residues of (S)-2-amino­propanoic acid [(S)-Ala] and (S)-2-amino-3-phenyl­propanoic acid [(S)-Phe], and protecting groups of tert-but­oxy­carbonyl (Boc) and benzyl ester (OBn). The tetra­mer folds into a right-handed mixed 11/9 helix stabilized by intra­molecular i,i + 3 and i,i − 1 C=O⋯H—N hydrogen bonds. In the crystal, the oligomers are linked by N—H⋯O=C hydrogen bonds into chains along the a-axis direction. The chloro­form solvent mol­ecules are inter­calated between the folded chains via C—H⋯O=C inter­actions.