A,/3-Unsaturated carboxamides

In addition to alkenes, functionalized alkenes can also be used as alkylating agents. Koltunov, Walspurger, and Sommer, have reported the alkylation of benzene with a,/3-unsaturated carboxamides in the presence of excess aluminum chloride [Eq. (5.72)]. The reaction takes place under mild conditions and gives the products in near-quantitative yields. Results with ortlro-dichlorobenzene and triflic acid are usually inferior. Triflic acid, however, can catalyze similar reactions of cyclic and open-chain unsaturated amines with benzene to give phenylalkylamines in excellent yields.180 The transformations are interpreted by invoking the involvement of dica-tionic intermediates 39 and 40. 

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