56874-95-4

A general synthesis of 2-fluoro-1-naphthols in two steps from 1-indanones is reported. The 1-indanones are first converted to difluoromethyl 2-fluoro-1-napthyl ethers by reaction with difluorocarbene source, trimethylsilyl 2-fluorosulfonyl-2,2-difluoroacetate (TFDA). These ethers are then converted in high yield to the respective naphthols by heating with a mixture of acetic acid and 48% HBr.

A novel decarboxylative fluorination process has been developed for the synthesis of ortho-hydroxy/amino arylfluorides from salicylic acid analogs, in which the ortho-hydroxy/amino group plays an important role in the transformation. In addition, various arylfluorides are obtained in good to excellent yields under mild conditions.

The first recyclable polymer-supported electrophilic fluorinating agent was prepared by reaction of molecular fluorine with the triethylenediamine motif that is grafted onto a poly(4-vinylbenzyl chloride-co-divinylbenzene) polyHIPE material. The resulting

The influence of a stoichiometric amount of ionic liquids (IL) on the fluorination of phenols in various solvents has been studied. The fluorination of phenol, 1-naphthol and resorcinol was carried out using 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (F-TEDA-BF4, Selectfluor) with the formation of 2-fluoro-, 4-fluorophenol, 2-fluoro-, 4-fluoronaphthol and 4-fluoro-, 4,6-difluoro-benzene-1,3-diol as the main products. The use of a stoichiometric amount of ionic liquid as an additive results in acceleration of the reactions. The effect is most significant at low temperatures. It has been found that solvent polarity has an essential effect on the difference in yields of fluoroproducts obtained in the presence of IL and without it.

A direct method for the synthesis of o-fluoronaphthols and o/p-fluorophenols has been developed by a catalytic ring expansion of indanones and 2-cyclopentenones, in which TMSCF2Br was used as a unique:CF2 source, a TMS transfer agent, as well as the Br- and F- releaser for the enolization, difluorocyclopropanation, desilylation, ring opening, defluorination, and aromatization sequence.

A facile and site-selective C-H bond fluorination of phenols using removable 2-pyridyloxy group as an auxiliary was developed. Alternatively, late-stage C-H bond fluorination of bioactive 2-phenoxyl nicotinate derivatives and diflufenican were also feasible under the present strategy.

Reactions of N-fluorobenzenesulfonimide with methylbenzenes, phenols, and phenol ethers were studied under solvent-free conditions. The rate constant ratio for the reactions with mesitylene and durene indicates polar mechanism of the process. Solvent-free fluorination of aromatic compounds with N-fluorobenzenesulfonimide in some cases is more selective than reactions with other N-F reagents in a solvent.

Methods of synthesis are described for a range of 1-alkyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane salts [R-N+(CH2CH2)3N+-F (X-)2, where R = CH3, CH2Cl, C2H5, CF3CH2, C8H17 and (X-)2 = (TfO-)2, (BF4-)2, (PF6-)2, (TfO-, BF4-), (TfO-, PF6-), (TfO-, FSO3-)] by direct fluorination (with neat F2 at ≤20 mmHg or F2-N2 blends at 1 atm pressure) of monoquaternary salts of 1,4-diazabicyclo[2.2.2]octane [R-+N(CH2CH2)3N X-] or their 1:1 adducts with boron trifluoride, phosphorus pentafluoride, or sulfur trioxide in acetonitrile at ca - 35°C. The results of site-selective electrophilic fluorination of diethyl sodio(phenyl)malonate [→ PhCF(CO2Et)2], 1-morpholinocyclohexene (→ 2-fluorocyclohexanone), phenol (→ 2- and 4-FC6H4OH), 1- and 2-hydroxynaphthalene (→ 2- and 4-FC10H6OH, and 1-FC10H6OH and 1,1-difluoro-2-oxo-1,2-dihydronaphthalene, respectively), acetanilide (→ 2- and 4-FC6H4NHCOCH3), anisole (→ 2- and 4-FC6H4OCH3) and sodium benzenesulfinate (→ PhSO2F) with these N-fluoroammonium salts are presented.

A new N-F fluorinating reagent 1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Accufluor NFTh) was effectively used for selective fluorination of polycyclic aromatics. Naphthalene was site-selectively fluorinated to 1-fluoronaphthalene, phenanthrene to 9-fluorophenanthrene, and pyrene to 1-fluoropyrene. In a series of substituted naphthalenes the regioselectivity and effectiveness of fluorination depended on the position and the nature of the substituents.

Hydroxy-substituted organic molecules were used as target molecules in investigations of the role of the reagent structure on the reactivity of three types of N-F class fluorinating reagents: 1-chloromethyl-4-fluoro-1,4-diazoniabicyclooctane bis(tetrafluoroborate) F-TEDA (1a), N-fluorobis(phenylsulfonyl)amine NSF (1b), and N-Fluoropyridinium heptafluorodiborate-pyridine (1/1) NFP (1c).Methanol is stable, but hydroquinone is very quickly transformed in acetonitrile to quinone with F-TEDA at room temperature: on the other hand, NSF is less reactive, while oxidation with NFP is achieved only at an elevated temperature; a structure variation of the hydroquinone derivatives did not influence oxidation.Fluorination was achieved with monohydroxy-substituted aromatic compounds; a similar trend concerning the reactivity of N-F reagent (1) was also observed in reactions with 1- and 2-naphthol, while 9-phenanthrol gave 10,10-difluoro-9-(10H)-phenanthrenone with F-TEDA in acetonitrile and 9,10-phenanthrenequinone with NSF.Dealkylation was observed in a reaction with 4-methoxyphenol; although the thio analogue gave bis(4-methoxyphenyl) disulfide, the reactivity was changed and NSF was more reactive than F-TEDA and NFP.

A series of alkyl- or (trifluoromethyl)-substituted N-fluoropyridinium-2-sulfonates 2a-h, differing in fluotinating power, were synthesized, and assessment was made of the effectiveness of each selective fluorinating agent.N-Fluoropyridinium-3- and -4-sulfonates 3 and 4 were also synthesized.Power-variables 2a-h were found to be highly selective fluorinating agents for a wide range of nucleophilic substrates such as activated aromatics, enol trialkylsilyl and alkyl ethers, active methylene compounds, activated olefins, and sulfides.Thus, phenol, naphthol, phenylurethane, and the trimethylsilyl ether of phenol were exclusively or highly selectively fluorinated at the o-position with 2f-h.Conjugated enol trialkylsilyl ethers of a steroid were regioselectively fluorinated at the 6-position with moderately powerful 2b-e.This regioselectivity increased with the bulkiness of the silyl part, and with the most bulky triisopropylsilyl group exclusive 6-fluorination was achieved.Preferential β-stereoselective fluorination at the 6-position was observed.N-Fluoropyridinium-2-sulfonates were activated with an acid.This acid-catalyzed fluorination led to the preferential p-fluorination of anisole.The present results can be explained based on the capacity of the 2-sulfonate anion to interact with the hydroxy group of phenol or naphthol, NH group of phenylurethane, silicon atoms of silyl ethers, or protons of acids.

The usefulness of the N-fluoropyridinium salt system as a source of fluorinating agents was examined by using substituted or unsubstituted N-fluoropyridinium triflates 1-11, N-fluoropyridinium salts possessing other counteranions 1a-d and 3a, and the counteranion-bound salts, N-fluoropyridinium-2-sulfonates 12 and 13. Electrophilic fluorinating power was found to vary remarkably according to the electronic nature of the ring substituents. This power increased as the electron density of positive nitrogen sites decreased, and this was correlated to the pKa values of the corresponding pyridines. By virtue of this variation, it was possible to fluorinate a wide range of nucleophilic substrates differing in reactivity. It is thus possible to fluorinate aromatics, carbanions, active methylene compounds, enol alkyl or silyl ethers, vinyl acetates, ketene silyl acetals, and olefins through the proper use of salts pentachloro 6 through 2,4,6-trimethyl 2, their power decreasing in this order. All the reactions could be explained on the basis of a one-electron-transfer mechanism. N-Fluoropyridinium salts showed high chemoselectivity in fluorination, the extent depending on the reactive moiety. In consideration of these Findings, selective 9α-fluorination of steroids was carried out by reacting 1 with tris(trimethylsilyl ether) 73 of a triketo steroid. Regio- or stereoselectivity in fluorination was determined by a N-fluoropyridinium salt structure. Steric bulkiness of the N-F surroundings hindered the ortho fluorination of phenols and aniline derivatives, while the capacity for hydrogen bonding on the part of the counteranions prompted this process, and the counteranion-bound salts 12 and 13 underwent this fluorination exclusively or almost so. Both bulky N-fluoropyridinium triflates 2 and 7 preferentially attacked the 6-position of the conjugated vinyl ester of a steroid from the unhindered β-direction to give a thermally unstable 6β-fluoro isomer. On the basis of these results, N-fluoropyridinium salts may be concluded to constitute a system that can serve as a source of the most ideal fluorinating agents for conducting desired selective fluorination through fluorinating capacity or structural alteration.

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Process for fluorinating an organic carbanion, which process comprises contacting and reacting, in a dry inert atmosphere, the compound of the formula selected from STR1 wherein STR2 is the carbanion, M is a counter ion, and X is a halide and a selected N-flouro-N-alkylsulfonamide.