N-Halogeno compounds. Part 18. 1-Alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts: user-friendly site-selective electrophilic fluorinating agents of the N-fluoroammonium class

Microwave fluorination: a novel, rapid approach to fluorination with Selectfluor®

“…Despite initial concerns over the thermal stability of Selectfluor 1 (1) [13], especially in bulk [14], the report of Banks et al [7] that such compounds were thermally stable to temperatures above 150 8C, gave us some cause for optimism. Our early experiments focused on the fluorination of anisole since electrophilic fluorination with (1) had previously been reported by Lal [1] using the standard conditions of refluxing in MeCN.…”

“…In a typical example the fluorination of a non-commercial pyrethroid insecticide (14) [23] with one equivalent of Selectfluor 1 , in MeCN at 150 8C for 20 min in a microwave reactor gave as Scheme 2. Table 3 Fluorination of anisole with commercially-available reagents (14) was determined by nOe and HMBC NMR experiments and a consideration of fluorine couplings in the 1 H NMR spectra.…”

“…Caution: Although we have conducted these experiments many times at the scales reported and no uncontrolled exothermic events or explosions have been observed, care is advised when undertaking this procedure, due to the potential thermal instability of Selectfluor 1 [13,14].…”

Selective fluorination of an aryl triazolinone herbicide intermediate

“…These fluorinating agents must only be prepared and used by experienced and fully trained personnel. The fluorination agents were prepared by known literature methods: XeF 2 [7], (CF 3 SO 2 ) 2 NF [8], Selectfluor 1 [9], CF 2 (OF) 2 [10], CF 3 OF [10], CH 3 C(O)OF [11], and CF 3 C(O)OF [12].…”

A new synthesis of 2-fluoro-1-naphthols

“…The only reported syntheses of 2-fluoro-1-naphthol (1a) appear to be those that involve electrophilic fluorination of 1-naphthol by various electrophilic fluorination reagents, which include fluoroxytrifluoromethane [1], CsSO 4 F [2,3], N-fluoro-N-alkylsulfonamides [4], N-fluoropyridinium triflate [5], 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (also known as F-TEDA) [6][7][8], and 4,6-bis(trifluoromethyl) N-fluoropyridinium-2-sulfonate (2) [9]. These reactions generally lead to preferential formation of the 2-fluoro isomer, although mixtures of both the 2-fluoro and the 4-fluoro isomers were usually reported (Scheme 1).…”