Abstract
The solution conformation of peptides rich in the α,α‐dialkylated amino acid Aib has proven to be a subtle problem, not because of helix/coil transitions, but rather because of α‐helical/310‐helical competition. A special series of peptides containing 75% Aib has been synthesized that feature identical amino acid composition but differing sequences; they are sequence permutation isomers. Nuclear magnetic resonance hydrogen‐bonding studies reveal that there is a sequence permutation induced transition between the two alternative helical forms within this set. The implications for the design and conformational prediction of helical Aib‐rich peptides are discussed.