Scheme 1. Synthesis of diketo[n]CPPs 3 and 4 (A) and DBP[n]CPPs 1 and 2 (B) (5 was used as a racemic mixture, hence all derived compounds are racemic. For simplicity, a single enantiomer is shown for 1–4); (C) molecular structure of 9 in the solid state (displacement ellipsoids are shown at the 50% probability level; hydrogen atoms are omitted for clarity).
