Using symmetry to monitor geared bond rotation in aromatic amides by dynamic NMR
Dynamic NMR proves that the fastest interconversion between conformers of simple tertiary aromatic amide 3 is racemization via a geared (correlated) rotation of both the Ar-CO and N-CO bonds. The symmetry of 3 is such that correlated and noncorrelated rotations are easily distinguishable, even without assignment of the NMR spectrum, simply by observing the number of peaks taking part in the exchange.
Bragg
RA
Department of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
Clayden
J