Li Yan-Feng, Dong Li-Hong, Wang Wei, Wang Qiang, Wang Shu-Yang, Zhao Peng, Chang Jun-Biao
College of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, China.
Guang Pu Xue Yu Guang Pu Fen Xi. 2009 Oct;29(10):2748-50.
The circular dichroism (CD) is an excellent method for determining the absolute stereochemistry of organic compounds. The CD spectra of four biphenyl compounds were determined by using CD spectrometer, and two pairs of symmetrical CD spectra were obtained. The absolute configuration of biphenyl bond was confirmed by the Cotton effect according to the CD rule. The CD spectrum of compound 3 shows a negative Cotton effect at 256 nm, and a positive Cotton effect at 220 nm, which predicts an S-configuration of biphenyl according to an experimental CD rule. Conversely, the CD spectrum of compound 3' displays a positive Cotton effect at 256 nm, and a negative Cotton effect at 219 nm, which predicts an R-configuration of biphenyl. And the regularity of oxazoline-mediated Ullmann reaction was obtained, too.
圆二色性（CD）是确定有机化合物绝对立体化学的一种出色方法。使用CD光谱仪测定了四种联苯化合物的CD光谱，得到了两对对称的CD光谱。根据CD规则，通过科顿效应确定了联苯键的绝对构型。化合物3的CD光谱在256nm处显示负科顿效应，在220nm处显示正科顿效应，根据实验CD规则预测联苯的构型为S型。相反，化合物3'的CD光谱在256nm处显示正科顿效应，在219nm处显示负科顿效应，预测联苯的构型为R型。同时也得到了恶唑啉介导的乌尔曼反应的规律。
