Interaction of pentafluoropyridine with 4-nitrophenol and pentafluorophenol in the presence of potassium fluoride and 18-crown-6-ether

The reactions of 4-nitro- and pentafluorophenols with C₅F₅N, 4-ArOC₅F₄N and 2,4-(ArO)₂C₅F₃N (Ar = 4-NO₂C₆H₄, C₆F₅) in the presence of KF and catalitic amounts of 18-crown-6- -ether at various temperatures have been investigated. The leaving ability of the C₆F₅O-group is shown to be higher than that of the 4-NO₂C₆H₄O-group in the reactions of 4-ArOC₅F₄N, 2,4-(ArO)₂C₅F₃N and 2,4,6-(ArO)₃C₅F₂N with F^?-anion, which is in agreement with the order of the basicity of anions (C₆F₅O^?<4-NO₂C₆H₄O^?). The reaction pathways of pentafluoropyridine with ArO^?-anions are discussed.