The remarkable configurational stability of ortho,ortho′-tetrafluoro substituted biphenyls: 2,2′,4,4′,6,6′-hexafluorobiphenyl-3,3′-dicarboxylic acid as a model
作者:Frédéric Leroux、Michaël Maurin、Nathalie Nicod、Rosario Scopelliti
DOI:10.1016/j.tetlet.2004.01.018
日期:2004.2
Optically active 2,2′,4,4′,6,6′-hexafluorobiphenyl-3,3′-dicarboxylic acid was obtained through its brucine salt. The half-life time for racemization was determined at various temperatures and the torsional barrier for racemization was calculated to be 25.4 kcal/mol. These results prove, contrary to textbook knowledge, that ortho,ortho′-tetrafluoro substituted biphenyls are resolvable.
光学活性的2,2 ',4,4 ',6,6 ' -hexafluorobiphenyl -3,3 '通过其番木鳖碱盐,得到二羧酸。在各种温度下确定消旋作用的半衰期,计算消旋作用的扭转势垒为25.4 kcal / mol。与教科书知识相反,这些结果证明了邻,邻′-四氟取代的联苯是可分辨的。