Metadynamics Simulations on the Key Factors of Handedness Induction for the N/C-Terminal Substituted Quinoline Oligoamide Foldamers

Metadynamics simulation has been used to describe the conformational energy landscapes of several helical quinoline oligoamides bearing β-pinene-derived pyridine at either the C or N terminus. Based on the experimental results, helix-sense preference for four types of foldamers with the chiral terminal group has been verified. To compare to the key factors of inducing handedness to helical-sense preference, a terminal group with three hydrogen bond sites is designed and corresponding foldamers are built. The calculated results show the delocalization effect and steric hindrance mainly responsible for a particular helix-sense preference for the investigated foldamers. The more hydrogen bonds between the terminal group and oligoamide units are formed, the more stable foldamers are.