N-Halogeno Compounds. Part 16. Perfluoro-(N-fluoro-N-(4-pyridyl) acetamide) - A New Site-Selective Electrophilic Fluorinating Agent.

Abstract Perfluoro-[ N -(4-pyridyl)acetamide] ( 2 ), prepared via direct fluorination of the sodium salt ( 4 ) of perfluoro-[ N -(4-pyridyl)-acetamide], readily fluorinates diethyl sodio (phenyl) malonate [ a PhCF(CO 2 Et) 2 ], 1-morpholinocyclohexene ( a 2-fluorocyclohexanone), anisole ( a 2- and 4-FC 6 H 4 OMe), and phenol ( a 2- and 4-FC 6 H 4 OH) under mild conditions. The sodium salt precursor ( 4 ) of this sidechain NF reagent ( 2 ) is easily made from pentafluoropyridine via the trifluoroacetylation of its 4-amino derivative or, more directly, by treating it with two equivalents of the monosodium salt of trifluoroacetamide.