- Microflow fluorinations of benzynes: Efficient synthesis of fluoroaromatic compounds
-
Fluorinated aromatic compounds are found in a variety of biologically active compounds, including clinical drugs and agrochemicals. Therefore, the synthesis of aryl fluorides is particularly important in the medicinal and process chemistry fields. In this
- Ikawa, Takashi,Masuda, Shigeaki,Akai, Shuji
-
p. 1153 - 1164
(2018/12/10)
-
- Synthesis of fluorinated aromatic compounds by one-pot benzyne generation and nucleophilic fluorination
-
The fluorination of substituted benzenes using fluoride ions under mild reaction conditions has been one of the most important challenges for the synthesis of biologically active fluorinated aromatic compounds; however, only a few synthetically useful methods are known. In this paper, it is reported that the nucleophilic fluorination of benzynes, generated from either 2-(trialkylsilyl)phenyl nonafluorobutanesulfonates or 2-(trialkylsilyl)phenols, meets this challenge. In particular, the fluorination starting from 2-(trialkylsilyl)phenols for fabricating aryl fluorides involves three sequential reactions in one-pot: the nonaflylation of phenols, benzyne generation, and nucleophilic fluorination of the benzynes. The regioselectivities of these reactions are controlled by the substituents at the C3-position of the benzynes. CSIRO 2014.
- Ikawa, Takashi,Masuda, Shigeaki,Nishiyama, Tsuyoshi,Takagi, Akira,Akai, Shuji
-
p. 475 - 480
(2014/04/03)
-
- Synthesis and studies of chemical properties of arylthallium(III) bis(tetrafluoroborates)
-
Synthesis of arylthallium(III)bis(tetrafluoroborates) was carried out and their pyrolysis was studied. Synthetic procedure for preparation of fluoroaromatic compounds is developed.
- Gun'kin
-
experimental part
p. 455 - 457
(2010/08/04)
-
- Efficient synthesis of aryl fluorides
-
Chemical Equation Presented Creating C-F bonds: A novel electrophilic fluorination of aryl and heteroaryl Crignard reagents has been discovered and was used for the efficient synthesis of various aryl fluoride derivatives (see picture; THF = tetrahydrofuran).
- Anbarasan, Pazhamalai,Neumann, Helfried,Beller, Matthias
-
experimental part
p. 2219 - 2222
(2010/06/17)
-
- Flash vacuum pyrolysis over magnesium. Part 1 - Pyrolysis of benzylic, other aryl/alkyl and aliphatic halides
-
Flash vacuum pyrolysis over a bed of freshly sublimed magnesium on glass wool results in efficient coupling of benzyl halides to give the corresponding bibenzyls. Where an ortho halogen substituent is present further dehalogenation gives some dihydroanthracene and anthracene. Efficient coupling is also observed for halomethylnaphthalenes and halodiphenylmethanes while chlorotriphenylmethane gives 4,4′-bis(diphenylmethyl)biphenyl. By using α,α′-dihalo-o-xylenes, benzocyclobutenes are obtained in good yield, while the isomeric α,α′-dihalo-p-xylenes give a range of high thermal stability polymers by polymerisation of the initially formed p-xylylenes. Other haloalkylbenzenes undergo largely dehydrohalogenation where this is possible, in some cases resulting in cyclisation. Deoxygenation is also observed with haloalkyl phenyl ketones to give phenylalkynes as well as other products. With simple alkyl halides there is efficient elimination of HCl or HBr to give alkenes. For aliphatic dihalides this also occurs to give dienes but there is also cyclisation to give cycloalkanes and dehalogenation with hydrogen atom transfer to give alkenes in some cases. For 5-bromopent-1-ene the products are those expected from a radical pathway but for 6-bromohex-1-ene they are clearly not. For 2,2-dichloropropane and 1,1-dichloropropane elimination of HCl occurs but for 1,1-dichlorobutane, -pentane and -hexane partial hydrolysis followed by elimination of HCl gives E, E-, E,Z- and Z,Z- isomers of the dialk-1-enyl ethers and fully assigned 13C NMR data are presented for these. With 6-chlorohex-1-yne and 7-chlorohept-1-yne there is cyclisation to give methylenecycloalkanes and -cycloalkynes. The behaviour of 1,2-dibromocyclohexane and 1,2-dichlorocyclooctane under these conditions is also examined. Various pieces of evidence are presented that suggest that these processes do not involve generation of free gas-phase radicals but rather surface-adsorbed organometallic species.
- Aitken, R. Alan,Hodgson, Philip K.G.,Morrison, John J.,Oyewale, Adebayo O.
-
p. 402 - 415
(2007/10/03)
-
- Process for the preparation of fluoro compounds from the corresponding amines
-
Compounds containing a primary amino group are converted into compounds containing a fluorine atom in place of the amino group by reaction of the amino compound with hydrogen fluoride and a nitrosating reagent under the influence of ultrasound or microwaves.
- -
-
-
- Preparation process of fluorine substituted aromatic compound
-
A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
- -
-
-
- Dehalogenation of organic halides by flash vacuum pyrolysis over magnesium: A versatile synthetic method
-
Flash vacuum pyrolysis over magnesium at 600°C results in efficient dehalogenation of a variety of organic halides and provides a preparatively useful method for C-C bond formation and other reactions.
- Aitken, R. Alan,Hodgson, Philip K. G.,Oyewale, Adebayo O.,Morrison, John J.
-
p. 1163 - 1164
(2007/10/03)
-
- Aryl fluoride syntheses involving reactions of aryllead triacetates with boron trifluoride-diethyl ether complex
-
Aryllead(IV) triacetates react at room temperature with BF3.Et2O to give the corresponding aryl fluoride in moderate to good yields; triarylboroxines, electron rich aryltrimethylsilanes and some arenes, which yield aryllead triacetates in acid catalysed reactions with lead tetraacetate, are converted directly into aryl fluorides when stirred with lead tetraacetate in BF3.Et2O. An investigation of the mechanism of the fluoro-deplumbation reaction indicates that it probably proceeds by acid catalysed heterolytic cleavage of the C-Pb bond to produce an aryl cation.
- De Meio,Morgan,Pinhey
-
p. 8129 - 8138
(2007/10/02)
-
- Synthesis of Fluorinated Derivatives of Benzofluoranthene and Indenopyrene and 8,9-dihydro-8,9-epoxybenzofluoranthene
-
The synthesis of several select fluorinated derivatives of benzofluoranthene and indenopyrene is described.In the benzofluoranthene series, the 8- and 9-fluoro derivatives have been prepared by Wittig reaction of the 1,2-bis salt of the appropriate fluorobenzene with acenaphthenequinone under phase-transfer conditions.The synthesis of 2-fluoroindenopyrene was achieved by photocyclization of 1-(β,β-difluorovinyl)benzofluoranthene followed by dehydrofluorination in methanolic sodium methoxide.This represents a new method for the construction of the indenopyrene skeleton. 8,9-Difluoroindenopyrene was prepared from 1-(2-amino-4,5-diflurophenyl)pyrene by diazotization followed by coupling in the presence of copper-bronze.In addition to these fluorinated derivatives, the synthesis of 8,9-dihydro-8,9-epoxybenzofluoranthene, a suspect ultimate tumorigenic metabolite of benzofluoranthene, is reported.This arene oxide was prepared from the trans-8,9-bromo acetate by benzylic bromination and subsequent treatment with sodium methoxide in anhydrous THF.
- Rice, Joseph E.,Czech, Anna,Hussain, Nalband,LaVoie, Edmond J.
-
p. 1775 - 1779
(2007/10/02)
-
