Abstract
Alkylaluminum halides react with Brønsted acids to liberate an alkane and generate a new Lewis acid. Using these reagents, Lewis acid catalyzed reactions can be run under aprotic conditions, even when acidic protons are produced in the reaction. The use of these reagents for Lewis acid catalyzed ene, Diels-Alder and cycloaddition reactions and Claisen rearrangements is described. These reagents are also useful initiators for cation-olefin addition reactions. In some cases the alkyl groups react as nucleophiles. While this is often undesirable, addition of an alkyl group to carbenium ion intermediates provides novel classes of compounds.