Quantifying macrocyclization-induced strain utilizing N -phenylimides as conformational reporters.

Incorporating an N -phenylimide unit into macrocycles enabled measurements of macrocyclization strains by comparing the N -phenylimide's conformational changes to similar units attached to a linear-chain control. Systems of larger macrocycles displayed negligible macrocyclization strain, while smaller macrocycles demonstrated proportionate effects, emphasizing the use of N -phenylimides as conformational reporters of macrocyclization strain.