QUINOLINIUM FLUOROCHROMATE (QFC), C9H7NH[CRO3F] - AN IMPROVED CR(VI)-OXIDANT FOR ORGANIC SUBSTRATES

Yellow-orange crystalline quinolinium fluorochromate (QFC) is easily p repared in a nearly quantitative yield by the interact ion of quinolin e with CrO3 and hydrofluoric acid iii 1 : 1.5 : 1 molar ratio. The rea gent is stable. Compared with pyridinium fluorochromate (PFC). the new reagent is more soluble in organic solvents and less acidic. QFC in C H2Cl2 readily oxidizes primary, secondary, and allylic alcohols to the corresponding carbonyls, benzoin to benzil, and anthracene and phenan threne to anthraquinone and 9.10-phenanthrenequinone. respectively. Ox idations work well also in a variety of sensitive environments, e.g. i sopropylidene functionality and trimethylsilyl ethers. Organic sulfide s are transformed to sulfoxides at room temperature. The facile oxidat ion of triphenylphosphine to triphenylphosphine oxide by QFC iii CH2Cl 2 or CH3CN provides a clear evidence for an oxygen-transfer reaction. The reduced product of QFC, isolated after such reactions. has been as certained to be C9H7NH[CrO2F]. a chromium(IV) species. The advantages of QFC have been highlighted.