Novel biphenyl organocatalysts for iminium ion-catalyzed asymmetric epoxidation
摘要:
Two novel chiral biphenyl iminium salts derived from L-acetonamine, containing electron-withdrawing 3,3'-substituents on the biphenyl unit, have been prepared and tested as asymmetric catalysts for epoxidation of prochiral alkenes. The results are compared with those achieved using the corresponding unsubstituted system. (c) 2012 Elsevier Ltd. All rights reserved.
A class of resist compositions sensitive to deep ultraviolet radiation includes a resin sensitive to acid and a composition that generates acid upon exposure to such radiation. A group of nitrobenzyl materials is particularly suitable for use as the acid generator.