Conformational communication between the Ar–CO and Ar–N axes in 2,2′-disubstituted benzanilides and their derivatives

Abstract

Benzanilides containing two or more potentially stereogenic amide axes exist in solution as mixtures of conformers which are detectable by NMR. For simple tertiary benzanilides carrying an ortho substituent on each ring, conformational control can be high (up to about 10 : 1) providing the substituents are large, indicating that the two axes are in conformational communication with one another. For more complex diamides, conformational communication breaks down, and mixtures of conformers are evident by NMR.