Treatment of triphenylphosphine with potassium hydrogen fluoride or hy
drogen fluoride-pyridine and diisopropyl azodicarboxylate in acetonitr
ile or tetrahydrofuran, at room temperature results in the clean forma
tion of difluorotriphenylphosphorane. Analogous results were obtained
with other phosphines such as tributylphosphine and tris(dimethylamino
) phosphine.