Triflyl fluoride

The sulfone is obtained by reaction of dimethyl sulfone with ethylmagnesium bromide and then with triflyl fluoride (CF3S02F, 3 M Co.), m.p. 115-116, yield 54%. 

The effectiveness of various sources of fluoride ion in the displacement of the trifluoromethanesulfonic group has been demonstrated while introducing a fluorine atom into the five-membered carbocyclic ring of a prostaglandin precursor Treat tnent of the corresponding triflyl derivative with potassium fluoride in acetonitrile or with cesium fluonde in refluxing diinethylformamide or hexamethylphosphoric... 

Benzoyl-6-deoxy-3-0-methyl-2-0-triflyl-a- (183) and -)8-L-glu-copyranosyl fluorides (184) afforded on treatment with BU4NF or CsF, 2-deoxy-2-fluoro-L-ma o derivatives, 185 (75%) and 186 (55%), respectively. 

Preparation of 2-fluorofuranoses is also important in relation to the synthesis of biologically active 2 -fluoro derivatives of nucleosides (see Section 111,4). Su and coworkers prepared the 2-triflates 236 and 239 through acid-catalyzed methanolysis of 3,5-di-O-benzyl-1,2-(9-isopropylidene-a-D-ribofuranose [to give 235 (major) and 238] and subsequent triflylation. On treatment with fluoride ion, the anomer 236 afforded exclusively the furan derivative 237, whereas the a anomer 239 gave the 2-fluoro compound 240... 

Deoxy-2-[ F]fluoro-D-mannose ( F-2DFM) was prepared through treatment of 201 (see Section 11,2) with F-Bu4NF(MeCN, 75°, 30 min) or K F crown ether, as reported for the cold synthesis. F-2DFM was also prepared from methyl 4,6-di-0-acetyl-3-C>-benzoyl-2-C>-triflyl-a-D-glu-copyranoside with amino(polyether)-supported, carrier-free [ F]fluoride. 

GABA HMG-CoA HMPA HT LDA LHMDS LTMP NADH NBH NBS NCS NIS NK NMP PMB PPA RaNi Red-Al RNA SEM SnAt TBAF TBDMS TBS Tf TFA TFP THF TIPS TMEDA TMG TMP TMS Tol-BINAP TTF y-aminobutyric acid hydroxymethylglutaryl coenzyme A hexamethylphosphoric triamide hydroxytryptamine (serotonin) lithium diisopropylamide lithium hexamethyldisilazane lithium 2,2,6,6-tetramethylpiperidine reduced nicotinamide adenine dinucleotide l,3-dibromo-5,5-dimethylhydantoin A-bromosuccinimide A-chlorosuccinimide A-iodosuccinimide neurokinin 1 -methyl-2-pyrrolidinone para-methoxybenzyl polyphosphoric acid Raney Nickel sodium bis(2-methoxyethoxy)aluminum hydride ribonucleic acid 2-(trimethylsilyl)ethoxymethyl nucleophilic substitution on an aromatic ring tetrabutylammonium fluoride tert-butyldimcthyisilyl fert-butyldimethylsilyl trifluoromethanesulfonyl (triflyl) trifluoroacetic acid tri-o-furylphosphine tetrahydrofuran triisopropylsilyl A, N,N ,N -tetramethy lethylenediamine tetramethyl guanidine tetramethylpiperidine trimethylsilyl 2,2 -bis(di-p-tolylphosphino)-l,r-binaphthyl tetrathiafulvalene... 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

SCHEME 13.1 Synthesis of the pseudopentasaccharide intermediate 9. CAN, ceric ammonium nitrate PMB, p-methoxybenzyl Pyr, pyridine TBAF, tetrabutylammonium fluoride Tf, triflyl. 

In another approach, 3,4-di-0-beiizyl-2-0-triflyl-l,6-anhydro-/i-D-mannopyranose (3) is treated with tetrabutyl- or tetramethylammonium fluoride in anhydrous acetonitrile, acetone, or tetrahydrofuran to yield 3,4-di-0-benzyl-2-fluoro-1.6-anhydro-2-deoxy-/TD-glucopyranose (4) as a syrup ([a]D — 28) in up to 91 % yield. With cesium fluoride in dimethylformamide only decomposition was observed in an attempted synthesis of 4 from 3. Fluoride 4 is converted into 2-fluoro-2-deoxy-D-glucose (2) in 70% yield by heating with 50% (v/v) methancsulfonic acid at 120 C for 30 minutes.t,( ... 

The epoxide-assisted displacement of triflyl groups by fluoride ion is reported to be an efficient approach to deoxyfluoro-sugars. Benzyl 2,3-anhydro-4-0-triflyl-pyranosides undergo inversion at C-4 with tetra-n-butylammonium fluoride (TBAF) at room temperature in good yield thus treatment of the triflate (34-) with TBAF in benzene for 24 h gave the 4-fluoro-sugar (35) in 60% yield. The mild conditions avoid many of the difficulties encountered in fluoride-... 

Triflyl chloride was also used for the preparation of fluoroalkyl trifluoromethanesulfonates that act as highly efficient fluoroalky-lating reagents, 10 times more reactive than the corresponding tosylates. Significant formation of fluoroalkyl ether side-products was observed when trifluoromethanesulfonyl fluoride was used. Fluoroalkyl p-nitrophenyl ethers were thus prepared in high yields, without side-elimination reactions (eq 7). ... 

Trimethylsilyl-3-triflyl benzamide gives benzyne intermediates through fluoride-mediated l,2 -elimination, while other silylated... 

Ac, acetyl Ar ", 3,5-bis(trifluoromethyl)phenyl Boc, /er/-butoxycarbonyl Bn, ben l cat, catalyst -Bu, /er/-butyl Cbz, benzyloxycarbonyl Cy, cyclohexyl Mes, 2,4,6-trimethylphenyl Fmoc. 9-fluorenylmethoxycarbonyl MOM, methoxymethyl Piv, pivaloyl I -Pr, isopropyl TBAF, tetrabutylammonium fluoride TBDPS, tert-butyldiphenylsilyl Tf. triflyl Tfe, trifluoroacetyl Tos, tosyl... 

The reaction of gaseous [ F] fluorine or [ F] acetyl hypofluorite with tri-Q-acetyl-D-galactal has allowed the synthesis of 2-deoxy-2[ Flfluoro-D-galactose. Nucleophilic displacements employing [ F] fluoride ions on either methyl 3-Q-benzyl-4,6-0-benzylidene-2-Q-triflyl-p-D-mannopyranoside or 1,6-anhydro-3,4-di-Q-benzyl-2-Q-triflyl-p-D-mannopyranose have given access to 2-deoxy-2-[ F]fluoro-D-glucose. 

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