The α‑Hydrazino-Peptide 8‑Helix: A Key Role for Homochiral Hydrazino Turns

8-Helix secondary structures have rarely been described in peptidomimetic foldamers. By combining the propensity of α-hydrazino acids to form hydrazino turns (i.e., stabilized C8 conformations) with the conformational restrictions induced by a four-membered ring, homooligomers of the cyclic α-hydrazino acid (R)-N-aminoazetidine-2-carboxylic acid (AAzC) adopt robust 8-helix architectures. These folded structures display contiguous homochiral hydrazino turns with an S configuration at each sp3 nitrogen.