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Stereodynamics of Bond Rotation in Tertiary Aromatic Amides
Author(s) -
Bragg Ryan A.,
Clayden Jonathan,
Morris Gareth A.,
Pink Jennifer H.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20020315)8:6<1279::aid-chem1279>3.0.co;2-7
Subject(s) - rotation (mathematics) , amide , chemistry , stereochemistry , slippage , asymmetry , uncorrelated , group (periodic table) , crystallography , single bond , kinetic energy , materials science , organic chemistry , mathematics , geometry , physics , statistics , quantum mechanics , composite material
The degree to which the rotations about the C−N and Ar−CO bonds of aromatic amides occur in a concerted manner was investigated by a variety of NMR and kinetic techniques. Otherwise complex kinetic analyses were simplified by exploiting symmetry and asymmetry in the N‐substituents of amides. In 2‐unsubstituted 1‐naphthamides bearing branched N‐substituents, most conformational changes about the amide group were by correlated rotation, though uncorrelated Ar−CO rotation also occurred to some extent. In 2‐substituted 1‐naphthamides, correlated rotation accounted for all of the Ar−CO rotations, though a significant amount of uncorrelated C−N rotation also occurred. Naphthamides bearing branched N‐substituents thus turn out to be efficient molecular gears: Compound 12 showed almost no gear slippage.