1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate): An electrophilic fluorinating agent

Selectfluor and Its Analogs Electrophilic Fluorination for Preparing Alkyl Fluorides

“…The reaction can be accelerated by the use of a substoichiometric amount of a Lewis acid. Indeed, zinc chloride catalyzed the fluorination of active methylene compounds with Accufluor (NFTh) in the presence of imidazole or collidine [47]. Another method to accelerate the rate of the fluorination is to carry out the reaction under microwave irradiation.…”

“…However, the reaction of dienol acetates with NFTh at room temperature in acetonitrile yielded selectively the desired 6-fluoro steroid in 89% yield (Eq. 24)[47]. The corresponding methyl dienol can also be fluorinated with NFTh albeit in 72% yield.…”

Relative Electrophilic Fluorinating Power as Assayed by Competitive Catalytic Halogenation Reactions.

“…HPLC: determination of enantiomer excess (ee) by using the Agilent 1050 series system equipped with a DAICEL Chiralcel OB-H column (4.6 Â 250 Â 5); t R in min. 1 H, 13…”

“…As our primary goal was to find the most-active fluorinating reagent compatible with our catalytic system, we turned our attention to NÀF derivatives already known to exhibit the desired reactivity with b-keto esters. Thus, 1,4-diazabicyclo[2.2.2]octane salt derivatives such as F-TEDA (see 9) [12] (also called Selectfluor TM ), or NFTh (see 10) [13] (also called Accufluor TM ), the activated pyridinium salts 11 [14], 12 [5a] [15], and 13 (also called Synfluor TM ) [16], as well as neutral activated fluoroamine derivatives such as NFSI (see 14) [17] and perfluoropiperidine 15 [18] were chosen for this study (Fig.). The results of the competitive halogenations are summarized in the Table. All reactions proceeded with total consumption of b-keto ester 5.…”

Nuclear fluorination of 2,4-diarylthiazoles with Accufluor®

“…On the other hand, a similar to larger amount of fluorination occurred when Accufluor 1 [1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate)][24] (4) was used, although the reaction still did not proceed to completion. However, considering that no chlorinated byproduct was formed, nor would it be expected using this reagent, chromatography to remove the residual starting material was simplified and a 43% yield of the 5-fluoro adduct 8a was achieved (Scheme 3).With this respectable outcome in hand, fluorination of the other thiazoles in the series was next examined.…”