Diastereoselective photochromism of a bisbenzothienylethene governed by steric as well as electronic interactions.
Diastereoselective photochromism of a bisbenzothienylethene governed by steric as well as electronic interactions.
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DOI：
10.1021/ja029535d
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发表时间：
2003-05
影响因子：
15
通讯作者：
Y. Yokoyama;H. Shiraishi;Yutaka Tani;Y. Yokoyama;Y. Yamaguchi
中科院分区：
文献类型：
--
作者：
Y. Yokoyama;H. Shiraishi;Yutaka Tani;Y. Yokoyama;Y. Yamaguchi
在双苯并噻吩基全氟环戊烯的一个苯并噻吩环的C-2上引入不对称中心，得到高度非对映选择性的光致变色体系。立体异构中心带有氢原子、甲基和甲氧基甲氧基。空间排斥和电子排斥在室温下在各种溶剂中产生87-88%的非对映体过量，其中80-85%转化为有色形式。对映选择性合成也进行了。在己烷中光照射后，重复观察到820 nm处的旋光度变化，其中开放形式和有色形式都不吸收光。
Introduction of an asymmetric center to C-2 of one of the benzothiophene rings of bisbenzothienylperfluorocyclopentene results in a highly diastereoselective photochromic system. The stereogenic center bears a hydrogen atom, a methyl group, and a methoxymethoxy group. The steric as well as the electronic repulsions gave an 87-88% diastereomer excess in various solvents at room temperature with 80-85% conversion to the colored form. The enantioselective synthesis was also carried out. Upon photoirradiation in hexane, a change in optical rotation at 820 nm, where neither the open form nor the colored form absorbs light, was observed repeatedly.