Dicationic Electrophiles from Olefinic Amines in Superacid
Yun Zhang, Aaron McElrea, Gregorio V. Sanchez, Jr., Dat Do, Alma Gomez, Sharon L. Aguirre, Rendy Rendy and Douglas A. Klumpp*
*Department of Chemistry and Biochemistry, The Michael Faraday Laboratories,
NIU, DeKalb, IL 60115-2862, Email: dklumpp
niu.edu
Y. Zhang, A. McElrea, G. V. Sanchez, Jr., D. Do, A. Gomez, S. L . Aguirre, R. Rendy, D. A. Klumpp, J. Org. Chem., 2003, 68, 5119-5122.
DOI: 10.1021/jo030024z
Abstract
A superacid-catalyzed reaction of various olefinic amines and related compounds with benzene gives addition products in good yields. The formation of reactive, dicationic electrophiles is proposed.
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formation of dicationic species
Details
This paper explores the superacid-catalyzed reactions of olefinic amines with benzene in triflic acid (CF3SO3H), yielding addition products in high yields (75-99%), including pharmaceutical agents like fenpiprane and prozapine. The proposed mechanism involves the formation of reactive dicationic electrophiles, supported by low-temperature NMR observations of diprotonated species. The study builds on the concept of superelectrophilic activation, first proposed by Olah in 1975, which involves enhanced reactivity of electrophiles in superacids. The research demonstrates that various olefinic amines and N-heterocycles can form dicationic intermediates in triflic acid, facilitating electrophilic aromatic substitution reactions. Additionally, the chemistry is applied to functionalize polystyrene beads with pendant amine groups, useful for acid-scavenging and combinatorial synthesis. The study highlights the significant reactivity of these dicationic intermediates, even with moderately deactivated arenes, and provides detailed experimental procedures and analytical data for the synthesized compounds. The work is supported by the NIH and acknowledges contributions from several researchers and the use of NMR instruments at the University of Southern California.
Key Words
Friedel-Crafts Alkylation, electrophilic aromatic substitution, diarylmethanes, alkylation of arenes
ID: J42-Y2003-160
