We obtained NMR spectra of (S )-oP 7 (CF 3 )( t Bu) in acetone-d 6 and benzene-d 6 to determine whether solvent has a significant effect on the strength of chiral induction. The de's in these solvents were (72 ± 11) % and (74 ± 11)%, respectively, identical to that in chloroform within experimental error. We conclude that there is little effect, at least within the range of solvents tested, which is consistent with the generally small solvent effects found for o-phenylene folding. DFT calculations can be used to predict and understand the sense of chiral induction for these systems. Potential energy scans were generated for the two possible twist senses of (S )-oP 7 (CF 3 )( t Bu) (see Supporting Information) and used to identify the overall conformational energy minima, which were then optimized. The results are shown in Figure . Different twist senses of the helix orient the chirality center and the CF 3 groups very differently with respect to each other. The calculations predict a significant difference in stability between these two conformers, 1.8 kcal/mol in favor of the observed (S,P) combination at the PCM(CHCl 3 )/ωB97-XD/cc-pVDZ level. This appears to be at least partly because of steric interactions; in the favored (S,P) conformer, the tert-butyl group is farther away from the nearest CF 3 (by 0.2 Å as measured between the nearest carbon atoms). Similar calculations carried out for oP 7 ( t Bu) indicate that without the CF 3 groups there is a much smaller difference in stability between the two forms (see Supporting Information). While the (S,P) configuration is still predicted to be favored, contrary to the experimental results, the difference is only 0.2 kcal/mol, consistent with the overall trend and the low observed de.