Premium
Structures and Reactivities of Iminium Ions Derived from Substituted Cinnamaldehydes and Various Chiral Imidazolidin‐4‐ones
Author(s) -
An Feng,
Paul Shyeni,
Ammer Johannes,
Ofial Armin R.,
Mayer Peter,
Lakhdar Sami,
Mayr Herbert
Publication year - 2014
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201402009
Subject(s) - iminium , chemistry , electrophile , ion , reaction rate constant , thermochemistry , kinetics , medicinal chemistry , computational chemistry , organic chemistry , catalysis , physics , quantum mechanics
A series of α,β‐unsaturated iminium ions derived from substituted cinnamaldehydes and C2‐ and C5‐substituted chiral imidazolidin‐4‐ones were isolated and characterized in solution and in the solid state. The kinetics of the reactions of the iminium ions with silyl ketene acetals were determined in dichloromethane at 20 °C. The resulting second‐order rate constants were used to estimate the electrophilicity E of the iminium ions according to the linear free energy relationship log k 2 (20 °C)= s N ( N + E ). The kinetics for the reactions of two of the iminium ions with tributylphosphine were studied by laser flash spectroscopy and their second‐order rate constants were found to agree within a factor of 2.2 with those calculated by using the linear free energy relationship above.