5,5,7,7-Tetrametyl-6,7-dihydro-5<i>H</i>-dibenzo[<i>c</i>,<i>e</i>]azepine

Abstract

5,5,7,7-Tetrametyl-6,7-dihydro-5H-dibenzo[c,e]azepine has been synthesized as a possible pro-chiral (or tropos) unit for the construction of a chiral catalyst and as a molecular chirality sensor for the absolute configuration assignment by chiroptical spectroscopy. A straightforward synthetic strategy for the preparation of the title compound in high overall yield through sequential addition of the four methyl groups on benzylic positions has been described. A VT-NMR study was used to determine the rotational barrier of the aryl–aryl bond in this biphenylazepine, revealing its torsional flexibility at room temperature, which makes the biphenylazepine suitable as both a chirality probe and a tropos moiety in chiral ligands.

Keywords

• dibenz[<i>c</i>,<i>e</i>]azepines
• chirality sensing
• atropisomerism
• nitrones