On the Nature of CH⋅⋅⋅FC Interactions in Hindered CF 3 C(sp 3 ) Bond Rotations

In cinchona alkaloid‐based scaffolds , hindered CF 3 rotations have been observed. The variation in barrier heights for the CF 3 rotations is controlled by the corresponding entropic changes when the substituents are changed from an allyl to a bulky 9‐methylanthracenyl group. Quantum chemical and experimental studies have shown that the noncovalent C3′H1⋅⋅⋅FC interactions in the studied cases possess a weak hydrogen bonding‐like character.