Document Type
Article
Language
eng
Publication Date
2005
Publisher
American Chemical Society
Source Publication
The Journal of Organic Chemistry
Source ISSN
0022-3263
Abstract
Reactive intermediates in the Friedel−Crafts acylation of aromatic donors are scrutinized upon their successful isolation and X-ray crystallography at very low temperatures. Detailed analyses of the X-ray parameters for the [1:1] complexes of different aliphatic and aromatic-acid chlorides with the Lewis acids antimony pentafluoride and pentachloride, gallium trichloride, titanium and zirconium tetrachlorides provide unexpected insight into the activation mechanism for the formation of the critical acylium carbocations. Likewise, the X-ray-structure examinations of aliphatic and aromatic acylium electrophiles also isolated as crystalline salts point to the origins of their electrophilic reactivity. Although the Wheland intermediates (as acylium adducts to arene donors) could not be isolated in crystalline form owing to their exceedingly short lifetimes, transient (UV−vis) spectra of benzenium adducts of acylium carbocations with hexamethylbenzene can be measured and directly related to Wheland intermediates with other cationic electrophiles that have been structurally established via X-ray studies.
Recommended Citation
Davlieva, M. G.; Lindeman, Sergey V.; Neretin, I. S.; and Kochi, Jay K., "Isolation, X-ray Structures, and Electronic Spectra of Reactive Intermediates in Friedel−Crafts Acylations" (2005). Chemistry Faculty Research and Publications. 653.
https://epublications.marquette.edu/chem_fac/653
Comments
Accepted version. The Journal of Organic Chemistry, Vol. 70, No. 10 (2005): 4013-4021. DOI. © 2005 American Chemical Society. Used with permission.
Sergey V. Lindeman was affiliated with the University of Houston at the time of publication.