Cookies Policy

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

I accept this policy

Find out more here

Mechanistic Aspects of the Substrate Ionization Step in Aminium Salt Catalyzed Cyclopropanation

No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
The full text of this article is not currently available.

Brill’s MyBook program is exclusively available on BrillOnline Books and Journals. Students and scholars affiliated with an institution that has purchased a Brill E-Book on the BrillOnline platform automatically have access to the MyBook option for the title(s) acquired by the Library. Brill MyBook is a print-on-demand paperback copy which is sold at a favorably uniform low price.

This Article is currently unavailable for purchase.
Add to Favorites
You must be logged in to use this functionality

Cover image Placeholder

The cyclopropanations of a series of m- and p-substituted trans-β-methylstyrenes (3) by ethyl diazoacetate (4), catalyzed by tris(4-bromophenyl)aminium hexachloroantimonate (1-) and also by tris(2,4-dibromophenyl)aminium hexachloroantimonate (2*+) have been studied by competition kinetics. For the reactions catalyzed by the milder aminium salt (1*+), the Hammett-Brown p values and the fact that the absolute rates are independent of the concentration of 4 establish that ionization to 3*+ is not reversible, but rate-determining. The dependence of the magnitude of p upon the absolute concentration of 3 indicates the operation of competing chain and catalytic mechanisms, i.e. the ionization of 3 by both product cation radicals and by the catalyst. The extremely low p value observed in the reactions catalyzed by 2*+ indicates the exclusive operation of a relatively unselective chain mechanism. These mechanistic assignments are further supported by the observation of the formation of the same products under electrochemical conditions, in the absence of a chemical catalyst, in closely comparable diastereoisomer ratios and with p values which correspond nicely with the p values observed for equipotential aminium salt catalysts.

Affiliations: 1: Department of Chemistry and Biochemistry, The University of Texas, Austin, Texas 78712, USA


Full text loading...


Data & Media loading...

Article metrics loading...



Can't access your account?
  • Key

  • Full access
  • Open Access
  • Partial/No accessInformation