Tertiary diamides of xanthene-1,8-dicarboxylic acid and biphenyl-2,2′-dicarboxylic acid exhibit a thermodynamic preference for anti stereochemistry which is inverted in the presence of Ti- or Sn-based Lewis acids, allowing interconversion between kinetically stable syn and anti diastereoisomeric atropisomers.
呫吨-1,8-二
羧酸和
联苯-2,2′-二
羧酸的叔二酰胺表现出反立体
化学的热力学偏好,这种偏好在以
钛或
锡为基础的
路易斯酸存在时会发生逆转,从而使动力学上稳定的同分异构体和反非对映异构体之间发生相互转化。