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26.5.4.1.1 Method 1: Fluorination of α-Alkoxy Ketones

DOI: 10.1055/sos-SD-026-00616

Parrain, J.-L.; Thibonnet, J.Science of Synthesis, (200526772.

1-Fluoro-4-hydroxy-1,4-diazabicyclo[2.2.2]octane bis(tetrafluoroborate) (Accufluor, NFTh) acting as a fluorine atom transfer reagent and with methanol as solvent enables direct regiospecific fluoro functionalization of the α-carbonyl position in ketones without prior activation of the target molecules.[‌156‌] A practical enantioselective fluorination reaction applicable to both cyclic and acyclic carbonyl compounds using commercially or readily available cinchona alkaloid derivatives and 1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor) has been proposed. Applied to α-alkoxy ketone 68, this method yields α-fluoro ketone 69 in 80% ee (Scheme 32).[‌157‌]

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References


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