Whereas only one atropisomer of 1,2,4,5-tetra(ortho)tolyl benzene was observed by X-ray diffraction in the solids, five conformational atropisomers were detected by low temperature NMR in solution. Their structures were assigned by a combination of NOE experiments, solvent effect and ab-initio calculations. Variable temperature dynamic NMR and bidimensional EXSY experiments allowed the barrier for the interconversion of these atropisomers to be determined (deltaG = 15.3 kcal mol-1).
Static and Dynamic Stereochemistry of the Conformational Atropisomers of Tetra(o-tolyl)benzene / L.Lunazzi; A.Mazzanti; M.Minzoni. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - STAMPA. - 70:(2005), pp. 10062-10066. [10.1021/jo051783f]
Static and Dynamic Stereochemistry of the Conformational Atropisomers of Tetra(o-tolyl)benzene.
LUNAZZI, LODOVICO;MAZZANTI, ANDREA;MINZONI, MIRKO
2005
Abstract
Whereas only one atropisomer of 1,2,4,5-tetra(ortho)tolyl benzene was observed by X-ray diffraction in the solids, five conformational atropisomers were detected by low temperature NMR in solution. Their structures were assigned by a combination of NOE experiments, solvent effect and ab-initio calculations. Variable temperature dynamic NMR and bidimensional EXSY experiments allowed the barrier for the interconversion of these atropisomers to be determined (deltaG = 15.3 kcal mol-1).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
