Atropisomerism of aromatic carbamates.
ortho-Haloarylcarbamates like 1-4 show a high rotational barrier about the N--aryl bond of up to 91.6 kJ mol(-1) as found for 1, which was determined by 2D exchange NMR spectroscopy (EXSY). It was further demonstrated that the height of the barrier not only depends on the substituents at the axis of chirality, but is also influenced by electronic effects.
Tietze
Lutz F
LF
Institut für Organische und Biomolekulare Chemie der Georg-August-Universität Göttingen, Tammannstraße 2, 37077 Göttingen, Germany. ltietze@gwdg.de
Schuster
Heiko J
HJ
von Hof
J Marian
JM
Hampel
Sonja M
SM
Colunga
Juan F
JF
John
Michael
M