Direct α-Fluorination of Ketones Using N-F Reagents

Abstract

The use of 1-fluoro-4-hydroxy-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Accufluor ^TM NFTh) as a fluorine­ atom transfer reagent and methanol as solvent enabled direct regiospecific fluorofunctionalization of the α-carbonyl position in ketones without prior activation of the target molecules. Methoxy or hydroxy substituted derivatives of 1-indanone, 1-tetralone and oxo derivatives of thiophene, benzo[b]thiophene, benzofuran and benzopyran were regiospecifically transformed to the corresponding α-fluoro derivatives in high yield, while 2α-fluoro-5α-cholestan-3-one (28) and 16α-fluoro-3β-hydroxy-5α-androstan-17-one (30) were regio- and stereospecifically obtained starting directly from the corresponding keto steroids.

Key words

fluorination - ketones - Accufluor ^TM NFTh - keto steroids

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