Kinetic studies of the additions of benzylamines to a noncyclic dicarbonyl group activated olefin, methyl $alpha$-acetyl-$eta$ -phenylacrylates (MAP), in acetonitrile at 30.0 ${^{circ}C}$ are reported. The rates are lower than those for the cyclic dicarbonyl group activated olefins. The addition occurs in a single step with concurrent formation of the $C_alpha$ -N and $C_eta$ -H bonds through a four-center hydrogen bonded transition state. The kinetic isotope effects ($k_H/k_D$ > 1.0) measured with deuterated benzylamines ($XC_6H_4CH_2ND_2$) increase with a stronger electron acceptor substituent ($deltasigma$ X > 0) which is the same trend as those found for other dicarbonyl group activated series (1-4). The sign and magnitude of the cross-interaction constant, ρXY, is comparable to those for the normal bond formation processes in the $S_N2$ and addition reactions. The relatively low ${Delta}H^ eq$ and large negative ${Delta}S^ eq$ values are also consistent with the mechanism proposed.