An efficient Rh(III)-catalyzed redox-neutral weak O-coordinating vinylation and allylation of arylacetamides with allylic acetates are described. A wide variety of arylacetamides containing primary, secondary, and tertiary amides and substituted allylic acetates was compatible for the reaction. The synthesized ortho-vinylated arylacetamides were converted into ortho-vinylated phenyl acetic acid and biologically useful 3-isochromanones. A possible reaction mechanism involving π-allyl rhodium intermediate was suggested and further confirmed through deuterium labeling studies. Copyright © 2019 American Chemical Society.