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Updated: Jan 21, 2026

Low-energy Cathodoluminescence for OxyNitride Phosphors
Published on: November 15, 2016
Electrostatically Enhanced Phosphoric Acids and Their Applications in Asymmetric Friedel-Crafts Alkylations
1Department of Chemistry , University of Minnesota , 207 Pleasant Street, SE , Minneapolis , Minnesota 55455 , United States.
Abstract:
A series of electrostatically enhanced phosphoric acid catalysts were synthesized and studied. These compounds possess two positively charged N-octylpyridinium or triarylphosphonium ion centers at the 3,3'-positions of the (R)-BINOL backbone to enhance reactivity and provide needed steric bulk for enantioselective transformations. Catalytic activities for Friedel-Crafts alkylations of indoles with trans-β-nitrostyrenes were studied. Both types of catalysts accelerate reaction conversions relative to noncharged analogues, and good enantioselectivities up to 90% ee are observed with the phosphonium-ion-tagged phosphoric acids. This transformation also can be scaled up to synthetically useful amounts, affording >250 mg of product without losing any reactivity or selectivity.
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