Substrate-Dependent Mechanistic Divergence in Decarboxylative Heck Reaction at Room Temperature

We report herein a Pd(II)-catalyzed Heck-type coupling between arene carboxylic acids and alkenes at room temperature. Mechanistically, the reaction proceeds in two distinct pathways where electron-rich substrates undergo a palladium(II)-catalyzed decarboxylation and electron-deficient substrates proceed through silver(I)-assisted decarboxylation. Dimethyl sulfoxide (DMSO) or sulfide ligands have positive and negative roles in the reaction outcome, respectively. The present protocol is combined for the peptide modification under mild reaction conditions.