Trifluoroselenoacetic Acid Makes Its Debut

An international team of chemists is reporting the first synthesis of trifluoroselenoacetic acid, CF₃C(O)SeH, a previously unknown strong acid with potential uses in organic synthesis (Inorg. Chem., DOI: 10.1021/ic101254k). The parent compound trifluoroacetic acid, CF₃C(O)OH, was first prepared in 1922. It’s a strong acid that has proven useful as a solvent and reagent in organic chemistry. In 1960, chemists reported the synthesis of the sulfur analog, trifluorothioacetic acid, CF₃C(O)SH, which is a slightly stronger acid and also a useful reagent. Now, Rosana M. Romano of the National University of La Plata, in Argentina, and colleagues have prepared the selenium version, which is estimated to be an even slightly stronger acid. Building on their earlier work to prepare the nonfluorinated selenoacetic acid, CH₃C(O)SeH, the researchers made CF₃C(O)SeH by treating CF₃C(O)OH with an excess amount of Woollins’ reagent, (C₆H₅)₂P₂Se₄. They isolated the new compound, which is a colorless liquid estimated to boil at 46 °C, with vacuum-line techniques and characterized it with a battery of spectroscopic tests and theoretical calculations. The compound’s reactivity, including photolysis to generate CF₃ radicals, suggests it could be another useful reagent.