Synthesis and conformational analysis are reported for molecules containing the trans-5- amino-3, 4-dimethylpent-3-enoic acid residue (ADPA, 1). This amino acid is a glycylglycine mimic, in which the central amide group is replaced with an E-tetrasubstituted alkene. It was anticipated that this isosteric replacement would promote specific local (β-turn) and nonlocal (β-hairpin) conformational preferences. Previous work has shown that the most common β ...
