Selective Fluorinations by Reagents Containing the OF Group

A New and Direct Trifluoromethoxylation of Aliphatic Substrates with 2,4‐Dinitro(trifluoromethoxy)benzene

“…[20e] Obviously, the best synthesis of trifluoromethyl ethers would be the direct introduction of the whole OCF 3 moiety. It was first done by radical condensation of olefins and trifluoromethyl hypofluorite, [22] which is highly hazardous and toxic. Then, numerous attempts to carry out nucleophilic trifluoromethoxylation with trifluoromethoxide salts failed since, generally, the CF 3 O À anion collapses into fluoride and fluorophosgene, even at low temperature (Scheme 2).…”

Fluorinations of α‐Seleno Carboxylic Acid Derivatives with Hypervalent (Difluoroiodo)toluene

“…The product was obtained in 95 % yield as pale yellow liquid. 1 [19] Obtained in 64 % yield as pale yellow solid after purification by flash chromatography with petroleum ether/EtOAc (8:2). R f = 0.2; m.p.…”

“…: 73-75°C. 1 H NMR (400 MHz, CDCl 3 ): δ = 3.60 (s, 2 H, CH 2 Se), 6.90-7.50 (m, 10 H, Ph), 8.02 (1 H, s broad, PhNH). The spectroscopic data are in agreement with those in literature.…”

“…[1] The substitution of a hydrogen atom with an isosteric fluorine atom allows chemists to probe reactivities and to synthesize compounds with important physical and biological properties of high value. The fluorinated products do not present appreciable steric differences towards the corresponding hydrogen compounds, but at the same time their electronic structures change, sometimes in a dramatic way.…”

Selectfluor: Mechanistic Insight and Applications

“…Initially, molecular fluorine was the sole source for electrophilic fluorinations, but because of the ease of FC formation and the extremely dangerous properties of F 2 (highly toxic, strong oxidant with little or no specificity, potential runaway free-radical reactions), the development of alternate sources of electrophilic fluorine was essential. The first electrophilic fluorine reagent, fluoroxytrifluoromethane (CF 3 OF), was reported by Barton et al [2] The introduction of other reagents followed, including perchloryl fluoride (FClO 3 ), [3,4] xenon difluoride (XeF 2 ), [5] nitrogen oxide fluorides, [6] and several other hypofluorides [7,8] (Scheme 1). Although these reagents served as a safer alternative to fluorine gas and found widespread application in research and industry, the need for a stable and nontoxic form of electrophilic fluorine still remained.…”