Site-selective functionalization of saturated azacycles such as pyrrolidines is one of central topics in organic synthesis and drug discovery. Although α-amido pyrrolidine derivatives are biologically practical scaffolds, catalytic α-C–N bond formation over α-C–C bond formation of these N-heterocycles remains considerably underexplored. We herein report the sulfur-assisted rhodium(III)-catalyzed sp³ C–H amidation of pyrrolidines with dioxazolones as amidating agents. Dioxazolones are used as robust amidationg sources as the sulfur atom coordinates tightly with transition-metals. The amenability of the thioamide directing group is elucidated by a series of control experiments.