Herein, we report the challenging and scantily explored Friedel-Crafts alkylation of electron-deficient arenes using a “catalyst activation” approach. Through strong hydrogen bonding with solvent hexafluoroisopropanol (HFIP) the Brønsted acidity of the catalyst is increased which stabilizes the transition states of the Friedel-Crafts reaction via concerted mechanism.
Polyethers based on 9,9-BIS-perfluoroalkyl-3,6-dihydroxy-xanthene or 9-aryl-9-perfluoroalkyl-3,6-dihydroxy-xanthene
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0518196A1
公开(公告)日:1992-12-16
Polyethers based on 9,9-bis-perfluoroalkyl-3,6-dihydroxy-xanthene or 9-aryl-9-perfluoroalkyl-3,6-dihydroxy-xanthene and another constituent selected from aryl sulfone, aryl ketone, benzonitrile, and imide. These polyethers are useful as dielectric films in electronic devices.