2-Chloro-2,3,3-trifluorobutanedioic acid → 2,2,3-Trifluorobutanedioic acid

To a stirring solution of the chlorotrifluorosuccinic acid (part b) (24.5 g) in 200 ml dioxane was added portionwise zinc metal (85 g) and the mixture was stirred at ambient temperature for 10 hours to yield a viscous liquid which was decanted from the unreacted zinc. Most of the dioxane was evaporated in vacuo. The residue was dissolved in 100 ml H2O and a solution of 7.7 ml of concentrated H2SO4 in 25 ml of water was added. The solution was extracted with ether (3×100 ml) and dried over anhydrous MgSO4. The organic layer was stripped to yield 8.3 g (32%) of the product as a crystalline solid.