Fujii Kohei, Todani Haruki, Ito Shigekazu, Mikami Koichi
Department of Chemical Science and Engineering, School of Materials and Chemical Technology , Tokyo Institute of Technology , O-okayama, Meguro-ku , Tokyo 152-8552 , Japan.
Org Lett. 2019 May 3;21(9):3387-3391. doi: 10.1021/acs.orglett.9b01131. Epub 2019 Apr 19.
Chiral C-symmetric phosphinic acids were designed based on sterically demanding and helical chiral perfluoroalkyl groups at the closest α-position advancing asymmetric reaction environment and catalytic activity. The perfluoroalkyl catalysts, [(CF)F] and [(CF)F] phosphinic acids, were synthesized via a stereoselective addition/cyclization sequence of methyl phosphinate and deoxofluorination. These new classes of Brønsted acid catalysts were applied to an asymmetric Friedel-Crafts reaction to give up to 89% yield and 82% R-enantioselectivity, which is higher than those obtained with the parent phosphoric acid (42% and 55.5% S).
基于紧邻的α位上具有空间位阻的螺旋手性全氟烷基设计了手性C对称次膦酸，以改善不对称反应环境和催化活性。通过次膦酸甲酯的立体选择性加成/环化序列和脱氟反应合成了全氟烷基催化剂[(CF)F]和[(CF)F]次膦酸。将这些新型布朗斯特酸催化剂应用于不对称傅克反应，产率高达89%，对映体选择性为82%R，高于母体磷酸（42%和55.5%S）的相应结果。
