CPP in the crystal structure. In comparison to related BINOL-derived macrocycles, the new nanohoop exhibits similar structural parameters, which is even true when comparing the BINOL torsion angle found in (R)-OH- [9]CPP with those observed in larger, less strained nanohoops. This finding indicates that the unusual catalytic activity described below are likely less due to a structurally deformed BINOL scaffold and rather due to confinement. We also carried out DFT calculations of the phosphoric acid macrocycle (S)-PO4H- [9]CPP and its precursor (S)-OH- [9]CPP at the B3LYP/6-31 G(d) level of theory (for further details see the S. I.). The optimized structures of (S)-PO4H- [9]CPP revealed the expected endo orientation of the phosphoric acid (Supplementary Fig. ), thus creating the desired confined reaction site.