N-Halogeno compounds Part 19 1: Electrophilic fluorinating agents of the multiple mono- N-fluoro class derived from nitrogen heterocycles

Abstract

Bis(4-fluoro-1,4-diazoniabicyclo[2.2.2]oct-1-yl)-ethane and -propane tetratriflates ( 4, 5), and 1,1′-difluoro-4,4′-bipyridinium ditriflate ( 6) were prepared by solution-phase direct fluorination of bis(4-aza-1-azoniabicyclo[2.2.2]oct-1-yl)-ethane or -propane ditriflate ( 10,11), and 4,4′-bipyridine respectively. The same technique was employed to convert the complex 4,4′-bipyridine · 2BF 3 to the mono-NF derivative F 3B·NC 5H 4-C 5H 4N +-F BF 4 − ( 7) and its monomethylated analogue (4-NC 5H 4)C 5H 4N +-CH 4 TfO − to F- +NC 5H 4-C 5H 4N +-CH 3 (TfO −) 2 ( 8). The results of site-specific electrophilic fluorination of some model substrates (1-morpholinocyclohexene, phenol, 2-naphthol, anisole, di- and tri-methoxybenzene) with 5,7 and 8 are presented.