N‐Aryl‐N‐methyl‐2‐tert‐butyl‐6‐methylaniline derivatives exhibit a rotationally stable N−C axially chiral structure and the rotational barriers around an N−C chiral axis increased with the increase in electron‐withdrawing character of para‐substituent on the aryl group. X‐ray crystal structural analysis and the DFT calculation suggested that the considerable change of the rotational barriers by the electron effect