Reaction of dialkyl ethers with either fluorine or Selectfluor® leads to the formation of unusual difluorinated polyether products in modest yields.

A review of how and why work in organofluorine chemistry developed in the group over the career of Professor Chambers is presented, based on a Plenary Lecture presented in the Moissan session at the 19th International Symposium on Fluorine Chemistry, August, 2009.(C) 2010 Elsevier B.V. All rights reserved.

Reactions of dialkyl ethers with either fluorine or Selectfluor (TM) led to the formation of unusual difluorinated polyether products in modest yields. A mechanism involving initial fluorination of the site adjacent to ether oxygen followed by elimination of hydrogen fluoride, reaction of the generated enol system with a further equivalent of fluorinating agent giving an oxonium system which reacts with water during aqueous work-up to lead eventually to the products observed, is suggested. (C) 2010 Elsevier B.V. All rights reserved.

This chapter contains sections titled: Substituent Effects of Fluorine or Fluorocarbon Groups on the SN2 Process Fluoride Ion as a Leaving Group References

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This chapter contains sections titled: Introduction Steric Effects Electronic Effects of Polyfluoroalkyl Groups The Perfluoroalkyl Effect Strengths of Unsaturated Fluoro-Acids and -Bases Fluorocarbocations Fluorocarbanions Fluoro radicals References

Attempts to develop a direct enantioselective fluorination protocol using elemental fluorine and an appropriate Lewis acid and chiral ligand system are described.

Direct fluorination of a range of benzaldehyde derivatives gives mixtures of fluorobenzaldehyde and benzoyl fluoride products in ratios that depend upon the nature of the ring substituent. Electron-withdrawing substituents give predominantly benzoyl fluoride derivatives, whereas electron-donating substituents lead to fluoroarene systems. Separation of ring-fluorinated products can be easily accomplished by esterification of the benzoyl fluoride side products. Scale-up of these processes to provide significant quantities of appropriate fluorobenzaldehyde systems has also been achieved using. continuous flow techniques.

The effect of fluorine as a substituent group on nucleophilic aromatic substitution is discussed, where a fluorine atom located ortho to the point of substitution may be of variable activating influence, whereas fluorine located para is slightly deactivating and meta is activating. A rationale of these effects is presented and evidence to support polar influences by ortho fluorine is advanced. The influence of CN, CF(3), CF(2)H and CFH(2) is also established by comparison of appropriate measured rate constants and compared with the activation effects of ring nitrogen. (C) 2008 Elsevier B.V. All rights reserved.

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Reactions of 3 beta-acetoxy-5 alpha-androstan-17-one with elemental fluorine and Selectfluor (R) are reported and give contrasting results. Fluorine gives a mixture of mono-fluorinated steroids in which fluorine atoms are attached to tertiary carbon sites whereas Selectfluor (R) gives fluoro-steroid systems arising from electrophilic aliphatic substitution of the most sterically accessible secondary saturated positions. The identities of the fluoro-steroid products were determined by NMR analysis and X-ray crystallography. (c) 2008 Elsevier B.V. All rights reserved.

Continuous flow microreactor technology has been used for the direct fluorination of a range of deactivated di- and tri-substituted aromatic systems. (c) 2006 Elsevier B.V. All rights reserved.

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Palladium catalysed Suzuki cross-coupling reactions between 2,4,6-tribromo-3,5-difluoropyridine and a short series of aromatic boronic acid derivatives gave 4-bromo-3,5-difluoro-2,6-diphenylpyridine derivatives arising from displacement of bromine atoms attached to positions ortho to ring nitrogen or the corresponding triaryl systems depending on the reaction conditions. Consequently, the use of polybromofluoropyridine scaffolds for the synthesis of polyfunctional heteroaromatic derivatives is expanded further.