- Synthesis of α-fluoro-β-lactones and their thermal conversion to 1-fluoroalkenes
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α-Fluoro-β-lactones have been synthesized and isolated for the first time from α-fluoro-β-hydroxy acids by using the couple TsCl/DMAP as lactonization agent. A detailed description of the synthesis and spectroscopic properties of α-fluoro-β-lactones is pr
- Ocampo, Rogelio,Dolbier Jr., William R.,Zuluaga, Fabio
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- Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
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Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
- Jereb, Marjan,Vra?i?, Dejan
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p. 747 - 762
(2018/01/17)
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- Palladium-Catalyzed Fluorination of Cyclic Vinyl Triflates: Effect of TESCF3as an Additive
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A method for the palladium-catalyzed fluorination of cyclic vinyl triflates has been developed. As with several previous palladium-catalyzed fluorination reactions using fluoride salts, controlling the regioselectivity presented a challenge in developing a practical synthetic procedure. The addition of triethyl(trifluoromethyl)silane (TESCF3) was found to effectively address this problem and resulted in drastically improved regioselectivities in this palladium-catalyzed fluorination reaction. This discovery, along with the use of a new biarylphosphine ligand, allowed for the development of an efficient and highly regioselective protocol for the fluorination of vinyl triflates. This method is compatible with a range of sensitive functional groups and provides access to five-, six-, and seven-membered cyclic vinyl fluorides.
- Ye, Yuxuan,Takada, Takashi,Buchwald, Stephen L.
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p. 15559 - 15563
(2016/12/09)
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- Direct fluorination of styrenes
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We have developed a practical method to synthesize fluorostyrene compounds. A mild and regioselective mono-fluorination reaction occurred smoothly for various di- and trisubstituted styrenes in the presence of RuCl3 and N-fluorobenzenesulfonimide (NFSI). A tandem alkyne hydroarylation-olefin fluorination reaction was also developed using an Au catalyst.
- Shao, Qian,Huang, Yong
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supporting information
p. 6584 - 6586
(2015/04/14)
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- Synthesis of monofluoroalkenes through selective hydrodefluorination of gem-difluoroalkenes with Red-Al
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A novel and practical approach for the selective hydrodefluorination of gem-difluoroalkenes using Red-Al as a reductant at room temperature in CH2Cl2 without any additional base and metal catalyst was reported. Various monofluoroalkenes were obtained in moderate to high yields with good E-selectivity.
- Wu, Jingjing,Xiao, Juan,Dai, Wenpeng,Cao, Song
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p. 34498 - 34501
(2015/04/27)
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- Metal-free, efficient oxyfluorination of olefins for the synthesis of α-fluoroketones
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A novel oxyfluorination of olefin reactions has been developed. The reactions involve a metal-free and green catalytic system for the synthesis of α-fluoroketones which is an important building block for organic synthesis. Moreover, this reaction system exhibits great functional group tolerance.
- Yang, Qiang,Mao, Liu-Liang,Yang, Bin,Yang, Shang-Dong
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supporting information
p. 3460 - 3463
(2014/07/21)
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- Monofluorovinyl tosylate: A useful building block for the synthesis of terminal vinyl monofluorides via suzuki-Miyaura coupling
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Monofluorovinyl tosylate was developed as a practical vinyl fluoride building block to couple with a variety of arylboronic acids in the presence of a palladium catalyst. The high stereoselectivity of 2-aryl-1-fluoroethene derivatives was achieved. This a
- Zhang, He,Zhou, Chang-Bing,Chen, Qing-Yun,Xiao, Ji-Chang,Hong, Ran
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p. 560 - 563
(2011/04/23)
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- Synthesis of monofluoroalkenes via Julia-Kocienski reaction
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Monofluoromethyl 3,5-bis(trifluoromethyl)phenyl sulfone 1 was synthesized and employed in Julia-Kocienski fluoroolefination reaction with various ketones and aldehydes. Optimal reaction conditions were found to be the treatment of substrates with KOH or C
- Prakash, G.K. Surya,Shakhmin, Anton,Zibinsky, Mikhail,Ledneczki, Istvan,Chacko, Sujith,Olah, George A.
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experimental part
p. 1192 - 1197
(2011/02/22)
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- 1-tert-Butyl-1H-tetrazol-5-yl fluoromethyl sulfone (TBTSO2CH2F): A versatile fluoromethylidene synthon and its use in the synthesis of monofluorinated alkenes via JuliaKocienski olefination
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1-tert-Butyl-IH-tetrazol-5-yl fluoromethyl sulfone (TBTSO 2CI-12F) has been developed as a new and efficient fluoromethylidene synthon for the synthesis of both terminal and internal monofluoroalkenes via JuliaKocienski olefination reaction. The base-mediated reaction between TBTSO2CI-12F and carbonyl compounds (aldehydes and ketones) provided terminal monofluoroalkenes in good yields with moderate E!Z selectivity. The dominance of E- or Z-fluoroalkenes could be controlled by selection of proper reaction solvent and temperature. TBTSO 2CI-12F reagent was also found to be readily CL-alkylated, acylated, and phenylsulfonylated to give corresponding CL-functionalized fluorosulfones, which could be used in the synthesis of alkyl-, acyl-, and phenylsulfonyl-substituted internal monofluoroalkenes via JuliaKocienski olefination reactions.
- Zhu, Lingui,Ni, Chuanfa,Zhao, Yanchuan,Ru, Jinbo
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supporting information; experimental part
p. 5089 - 5100
(2010/08/20)
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- Transformations of organic molecules with F-TEDA-BF4 in ionic liquid media
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The transformations of organic molecules with F-TEDA-BF4 (1) were investigated in the hydrophilic ionic liquid (IL) 1-butyl-3-methyl- imidazolium tetrafluoroborate ([bmim][BF4], 2) and the hydrophobic IL 1-butyl-3-methyl-imidazolium hexafluorophosphate ([bmim][PF6], 3). The range of substrates included alkyl substituted phenols 4a-c, 9, 13, 1,1-diphenylethene (15), alkyl aryl ketones 19-22, aldehydes 23-25 and methoxy-substituted benzene derivatives 26-30. The evaluation of the outcome of reactions performed in IL media in comparison to those of the corresponding reactions in conventional organic solvents revealed that the transformations in IL are less efficient and selective. The effect of the presence of a nucleophile (MeOH, H2O, MeCN) on the course of reaction was also studied.
- Pavlinac, Jasminka,Zupan, Marko,Stavber, Stojan
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experimental part
p. 2394 - 2409
(2009/12/03)
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- A new synthesis of α-fluorovinylsulfones utilizing the Peterson olefination methodology
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α-Fluoro-α-silyl-substituted sulfones 1 are readily prepared from fluoromethyl phenyl sulfone and the appropriate silyl chloride. The use of TBSCl improves both the stability and yield of 1. Lithium derivatives 4 undergo a smooth Peterson olefination reaction with less-enolizable carbonyl compounds to give moderate to good yields of the expected α-fluorovinylsulfones 6, in some cases with high E-stereoselectivity. One-pot reaction with 4 generated in situ from fluoromethyl phenyl sulfone in tetrahydrofuran (THF) also proceeds smoothly, particularly with aldehydes.
- Asakura, Noriaki,Usuki, Yoshinosuke,Iio, Hideo
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- Utility of silicon tetrafluoride as a catalyst of reactions with xenon difluoride: Fluorinations of phenyl alkenes and benzaldehydes
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Application of silicon tetrafluoride to fluorinations with xenon difluoride as a catalyst is investigated. It was found that vic-difluorination of phenyl alkenes and transformation of benzaldehydes to difluoromethoxybenzenes using xenon difluoride are enhanced by silicon tetrafluoride.
- Tamura, Masanori,Takagi, Toshiyuki,Quan, Heng-Dao,Sekiya, Akira
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p. 163 - 166
(2007/10/03)
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- Magnesium alkylidene carbenoids: Generation from 1-halovinyl sulfoxides with Grignard reagents and studies on their property, mechanism, and some synthetic uses
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Magnesium alkylidene carbenoids were generated from 1-halovinyl sulfoxides, derived from ketones and aryl halomethyl sulfoxide, through the ligand exchange reaction of sulfoxides with Grignard reagents. The generated magnesium alkylidene carbenoids were found to be stable at -78 °C for over 30 min. The carbenoids reacted with aldehydes to give the adducts in moderate yields; however, they were found to be relatively unreactive to usual electrophiles. The generated magnesium alkylidene carbenoid exists in equilibrium between an α-halo alkenyl Grignard reagent and an alkylidene carbene-magnesium halide complex. Halogen exchange and geometrical isomerization of the alkylidene carbenoids were observed. 1-Chlorovinyl sulfoxides reacted with excess aryl Grignard reagents to give alkenyl Grignard reagents having an aryl group. These Grignard reagents reacted with several electrophiles to give tetra-substituted olefins in moderate to good yields.
- Satoh, Tsuyoshi,Takano, Koji,Hiroyuki, Ota,Someya, Hideaki,Matsuda, Kenji,Koyama, Mai
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p. 5557 - 5574
(2007/10/03)
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- Stereospecific synthesis of 1-fluoro olefins via (fluoro-vinyl)stannanes and an unequivocal NMR method for the assignment of fluoro olefin geometry
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(E)- and (Z)-Fluorovinyl sulfones (II) form (fluorovinyl)stannanes (III) on treatment with two equivalents of tributyltin hydride and a catalytic amount of AIBN; the free radical catalyzed reaction proceeds with retention of configuration for 2,2-disubstituted fluorovinyl sulfones (IIa and IIb). Conversion of III to 1-fluoro olefins (IV) is a stereospecific reaction and provides a general method to (E) and (Z) fluoro olefins. The utility of this method is exemplified by the synthesis of the deutero fluoro olefins 27, nucleosides 32 and 34, and the amino acids 43 and 47. Proton observe, 19F irradiated (1H-{19F}) NOE difference spectroscopy was used for the first time as an unequivocal method for the assignment of olefin geometry for fluorovinyl sulfones, (fluorovinyl)stannanes and fluoro olefins.
- McCarthy,Huber,Le,Laskovics,Matthews
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- 1-Fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) as a new, effective reagent for selective fluorofunctionalisation of alkenes under mild reaction conditions
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1-Fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) Accufluor NFTh) is confirmed as a highly effective reagent for introducing a fluorine atom into organic molecules across a phenyl-substituted carbon-carbon double bond. Quantitativ
- Stavber, Stojan
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p. 6769 - 6772
(2007/10/02)
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- The Reaction of XeF2 with Trialkylvinylstannanes: Scope and Some Mechanistic Observations
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The combination of a vinylstannane with xenon difluoride in the presence of silver(I) triflate results in a very rapid process leading to the corresponding vinyl fluoride.The reaction is regio- and stereospecific and does not require stoichiometric Ag(I).No evidence could be obtained of radical intermediates on the reaction pathway leading to the vinyl fluorides.A symmetrical dimer derived from the vinylstannane, which was obtained as a reaction byproduct, was shown to arise from oxidative coupling by the silver salt.The results are consistent with an electrophilic mechanism following an initial interaction of the vinylstannane with Ag(I).
- Tius, Marcus A.,Kawakami, Joel K.
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p. 3997 - 4010
(2007/10/02)
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- A NEW METHOD FOR THE ELECTROPHILIC FLUORINATION OF VINYL STANNANES.
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A new method for the electrophilic fluorination of vinyl stannanes using commercially available 1-chloromethyl-4-fluoro-1,4-diazoniabicyclooctane bis(tetrafluoroborate) (1) has been developed.
- Matthews, Donald P.,Miller, Shawn C.,Jarvi, Esa T.,Sabol, Jeffrey S.,McCarthy, James R.
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p. 3057 - 3060
(2007/10/02)
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- N-Fluorobisimides: Reactions with Some Olefins via α-Fluoro Carbocationic Intermediates
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N-Fluorobisimides are a new class of electrophilic fluorinating agents.Reaction of (CF3SO2)2NF (1) with olefins gave various products, depending on the reaction conditions and the structure of the substrate.In solvents of higher nucleophilicity such as H2O, acetic acid, aqueous HCl, and (HF)nPy, α-fluorohydrins and their acetates, α,β-chlorofluoro- and α,β-difluoroalkanes were obtained.In acetic acid, trans-stilbene and tetraphenylethylene produced the rearranged, nonfluorinated aldehyde and ketone.Evidence is presented for the reactions proceeding via a one-electron transfer mechanism involving α-fluorocarbocationic intermediates.
- DesMarteau, Darryl D.,Xu, Ze-Qi,Witz, Michael
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p. 629 - 635
(2007/10/02)
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- α-FLUOROMETHYL-N-METHYL-PHENYLSULPHOXIMINE: A NEW FLUOROMETHYLENATION REAGENT
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Treatment of aldehydes or ketones with the anion derived from α-fluoromethyl-N-methyl-phenylsulphoximine produces adducts which afford fluoro-olefins on reductive elimination.
- Boys, Mark L.,Collington, Eric W.,Finch, Harry,Swanson, Stephen,Whitehead, John F.
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p. 3365 - 3368
(2007/10/02)
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- THE PREPARATION OF α-FLUOROSULFOXIDES AND VINYL FLUORIDES
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Treatment of thioacetals with HgF2 in anhydrous acetonitrile, followed by oxidation with MCPBA results in the formation of α-fluorosulfoxides, which can be pyrolyzed to give vinyl fluorides.
- Purrington, Suzanne T.,Pittman, James H.
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p. 3901 - 3904
(2007/10/02)
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- PHOTOCHEMISTRY OF ORGANOHALOGENO-COMPOUNDS. PART XIX THE EFFECT OF FLUORINE ON PHOTOCHEMICAL CARBON-HALOGEN BOND CLEAVAGE
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Irradiation of 1,1-diphenyl-2-fluoro-2-haloethenes at λ = 253.7 nm gave 1,1-diphenyl-2-fluoroethene and the rearranged product trans-fluorostilbene.The phototransformation depended on the halogen present and the solvent used.Introduction of fluorine on th
- Gregorcic, A.,Zupan, M.
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p. 313 - 322
(2007/10/02)
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- Reaction of epoxides with diethylaminosulfur triflouride
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Diethylaminosulfur triflouride (DAST) reacts with epoxides (oxiranes) to form geminal diflourides, vicinal diflourides, and bis(2-fluoroalkyl) ethers. Thus cyclopentene oxide gave cis-1,2-difluorocyclopentane and bis(2-fluorocyclopentyl) ether; cyclohexene oxide gave cis-1,1-difluorocyclohexane and bis(2-fluorocylohexyl) ether; styrene oxide gave 1,1-difluoroethylbenzene and 1,2-difluoroethylbenzene; and cis- and trans-stilbene oxides gave mixtures of meso- and racemic 1,2-difluoro-1,2-diphenylethanes together with 1,1-difluoro-2,2-diphenylethane resulting from a rearrangement. Cyclooctene oxide and cyclohexene sulfide do not react appreciably under the same conditions.
- Hudlicky, Milos
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p. 373 - 384
(2007/10/02)
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- FLUORINATION WITH CAESIUM FLUOROXYSULPHATE. ROOM TEMPERATURE FLUORINATION OF PHENYL SUBSTITUTED OLEFINS
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Room -temperature fluorination of 1,1-diphenylethene with caesium fluoroxysulphate in methylene chloride resulted in an addition elimination process, thus yielding 1,1-diphenyl-2-fluoroethene, while in the presence of nucleophile containing species, i.e.,
- Stavber, Stojan,Zupan, Marko
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p. 5035 - 5044
(2007/10/02)
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- A Novel and Efficient Synthesis of Fluoromethyl Phenyl Sulphone and Its Use as a Fluoromethyl Wittig Equivalent
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A new synthesis of fluoromethyl phenyl sulphone (2) and the reaction of its conjugate base (3) with carbonyl compounds provides β-fluoro-alcohols (5), which are utilized to prepare terminal vinyl fluorides (8) via α-fluoro-α,β-unsaturated sulphones (6).
- Inbasekaran, Muthiah,Peet, Norton P.,McCarthy James R.,LeTourneau, Michael E.
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p. 678 - 679
(2007/10/02)
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- Ylide-Carbene Chemistry. Synthesis of 1,1-Difluoro-1-alkenes
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The reaction between nonstabilized alkylidenetriphenylphosphoranes and chlorodifluoromethane has been found to be a useful alternative to the Wittig reaction for the synthesis of many difluoromethylene olefins.Both primary and secondary ylides which do not contain strongly electron-withdrawing substituents within the alkylidene portion of the ylide react with chlorodifluoromethane to give the corresponding difluoromethylene olefins in yields which are significantly better than those obtained by the Wittig reaction.The formation of triphenylphosphine oxide is avoided, and all phosphorus-containing moieties can be recovered and recycled.The reaction proceeds by initial dehydrochlorination of chlorodifluoromethane by the ylide to generate difluorocarbene.The intermediate difluorocarbene is then trapped by a second equivalent of the nucleophilic ylide.Mechanistic evidence indicates that either a zwitterionic intermediate or a three-membered cyclic phosphorane can account for the 1,1-difluoro-1-alkene products.The isolation of several 1-hydro-1-fluoro-1-alkene products such as FCH=CHPh, FHC=CPh2, and FHC=CHCH=CHPh after steam distillation of the reaction mixtures, however, can only be accounted for via a three-membered cyclic phosphorane.
- Wheaton, Gregory A.,Burton, Donald J.
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p. 917 - 927
(2007/10/02)
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- Room-temperature Fluorination of Alkenes with Caesium Fluoroxysulphate
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Room-temperature fluorination of 1,1-diphenylethene with caesium fluoroxysulphate resulted in the formation of 2-fluoro-1,1-diphenylethene; norborn-2-ene gave only 7-fluoronortricyclene and 7-syn-fluoronorborn-2-ene, while reactions with various cyclic enol acetates gave α-fluorocycloalkanones in high yield.
- Stavber, Stojan,Zupan, Marko
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p. 795 - 796
(2007/10/02)
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- Reactions of 1,1-Diarylethylenes and 1,1-Diarylimines with CF3OF
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1,1-Diphenylethylene (1) reacts with CF3OF to give products 2-6 in a cationic process. 9-Ethylidenefluorene reacts with CF3OF to yield 8 and 10.Amitriptyline (12) furnished a difluoro adduct (13) in low yield.Benzophenone oxime (14) gave a Beckmann rearrangement product on reaction with CF3OF.Fluorenone anil (15) produced mainly fluorenone from reaction with CF3OF.Diazepam (16) gave a 1:1 adduct (18) with CF3OF.The adduct 18 reacted further to give an oxidation product (17).
- Patrick, Timothy B.,Cantrell, Gary L.,Inga, Sandra M.
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p. 1409 - 1413
(2007/10/02)
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