Theoretical investigation on the mechanism of rhodium-catalyzed C-H dienylation of acetanilide with aryl allene

The reaction mechanisms on the rhodium-catalyzed C-H dienylation of acetanilide with aryl allene have been computationally investigated by employing density functional theory (DFT) calculations. Three main steps, C-H activation, olefin migratory insertion, and beta-hydride elimination, respectively, are included in this reaction. Olefin inserttion is the rate-determining step for this reaction. The electronic effect could account for the observed regioselectivity. For comparison, the coupling reaction of acetanilide with F-aryl allene was also studied. The higher barrier is in agreement with the lower yields observed in the experiment.