The barriers to enantiomerization of a series of axially chiral biaryl analogues of 4-(dimethylamino)pyridine (DMAP) 1−10 were determined experimentally by means of dynamic HPLC measurementsand racemization studies. The barriers to rotation in derivatives 1−6 (based on the bicyclic5-azaindoline core) were lower than those in the corresponding derivatives 7−10 (based on themonocyclic DMAP core). Semiempirical (PM3), ab initio Hartree−Fock (HF/STO-3G), and densityfunctional theory (DFT/B3LYP/6-31G*) calculations reveal that these differences in barriers torotation are the result of differing degrees of hybridization of the non-pyridyl nitrogen in theenantiomerization transition states (TSs). The importance of heteroatom hybridization as a factorin determining nonsteric contributions to barriers to rotation in azabiaryls of this type is discussed.