tert-Butyl 3-diazo-2-oxopyrrolidine-1-carboxylate synthesized on multigram scale has been employed to introduce a privileged NH-2-pyrrolidone moiety via oxygen, sulfur and nitrogen atom to partner molecules via Rh^II-catalyzed X–H insertion followed by Boc group removal. Further manipulation of pyrrolidine moiety has been exemplified.