The C-H alkylation of arylacetamides with activated alkenes such as substituted acrylates and vinyl sulphone in the presence of a ruthenium catalyst and organic acid via the weak O-coordination under the redox free version is described. The present protocol was effective with different substituted arylacetamides including secondary and tertiary amides. The reaction mechanism including the ortho C-H bond activation, migratory insertion, and protonation by acetic acid was suggested and supported by the deuterium labeling experiments, competitive experiments, and DFT calculations including TS analysis. Copyright © 2019 American Chemical Society.