The mild and efficient palladium-catalyzed pyrrolidin-2-yl and tetrahydrofuran-2-yl methylation of (hetero)arenes has been developed. A wide range of (hetero)arenes underwent the regioselective thianthrenation to generate the arylthianthrenium triflate, and the developed Pd-catalyzed alkene carboamination and carboalkoxylation reactions afforded the corresponding biologically important pyrrolidine and tetrahydrofuran derivatives. Mechanistic studies indicated that this reaction proceeds through a syn-heteropalladation mechanistic pathway. The demonstrated late-stage functionalization and enantioselective reaction will help to promote the potential application of the established method in organic synthesis and related fields.