Disclosed is a method for producing fluorinated organic compounds, including hydrofluoropropenes, which preferably comprises converting at least one compound of formula (I): CF3CFnCHmXa-m  (I) to at least one compound of formula (II) CF3CZCHZ  (II). where each X is independently Cl, F, I or Br; each Z is independently H or F; n is 1 or 2; m is 1, 2 or 3, provided that when n is 1, m is 1 or 2; a is 2 or 3, and a-m≧0. Certain embodiments include the step of reacting fluorinated C2 olefin, such as tetrafluoroethylene, with a Cl addition agent under conditions effective to produce a compound of formula (I).