Cu-promoted reactions of 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) with dialkylphosphonates produced dialkyl (2,2,2-trifluoroethyl)phosphonates efficiently under mild conditions by successively activating the two inert C–Cl bonds in HCFC-123. These reactions can be efficiently carried out on a >30 g scale with moderate to good yields.