It was originally suggested by Friedel and Crafts1 that the reactions which later came to bear their name proceed by way of organoaluminum compounds. Later Leone2 and co-workers studied the possibility of organoaluminum intermediates by reacting organoaluminum iodide etherates with alkyl halides, acid halides, and ketones. With alkyl halides they obtained small quantities of homologs of benzene together with large amounts of resins, whereas acid halides and ketones gave chiefly condensation products. They concluded that alkylation may proceed by way of an organoalmninum compound, but that ketone synthesis does not involve intermediate organoaluminum compounds because of condensation reactions. Ketones usually exist as complexes with aluminum chloride in the Friedel-Crafts reaction and it has been found that these complexes do not give condensation products when treated with organoalurninum halides under moderate conditions. An excellent recovery of ketone was obtained upon hydrolysis. Furthermore, good yields of ketones were obtained by interaction of ether-free organoaluminum halides with either acid chlorides or complexes formed from acid chlorides and aluminum chloride. Likewise, acid anhydrides give good yields of the expected ketones or keto-acids when reacted with ether-free organoalurninum halides. One may conclude, therefore, that the formation of carbonyl derivatives in the Friedel-Crafts reaction is not inconsistent with the possible intermediate formation of organoaluminum compounds.
Proceedings of the Iowa Academy of Science
©1939 Iowa Academy of Science, Inc.
Haubein, Albert H.; Apperson, Lester D.; and Gilman, Henry
"The Role of Organoaluminum Compounds in the Friedel-Crafts Reaction,"
Proceedings of the Iowa Academy of Science, 46(1), 219-220.
Available at: https://scholarworks.uni.edu/pias/vol46/iss1/46