Unambiguously confirmed by low-temperature in situ NMR experiments, X-ray diffraction and vibrational spectroscopy, phosphonium-carbenium superelectrophiles are shown to be generated in strong acidic conditions. Representing crucial intermediates, their exploitation allows for the synthesis of unprecedented fluorinated (cyclic) phosphine oxides.
Keywords: cyclization; fluorination; phosphine oxide; superacid; superelectrophile.
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.