Difluoro-2,3-dihydrobenzofuran

Anodic fluorination of ethyl (3-benzofuranyl)acetate was applied to the syntheses of 2,3-difluoro-2,3-dihydrobenzofuran derivatives, togedier with 2-fluoro-3-hydroxy derivatives as minor products <03SL1631>. 

Fluorinations with Silver Fluoride. Reaction of AgF with alkyl and aryl halides often results in the formation of the corresponding fluorides usually under mild conditions. With gemi-nal dihalides, this conversion has been shown to involve a carbo-nium ion intermediate (eq 1). Chloro quinones react with AgF under high pressure and temperature conditions to give partial conversion to the fluoro quinone (eq 2). Cis- and trans-2,3-difluoro-2,3-dihydrobenzofuran can be similarly obtained by the reaction of AgF with trans-2,3-dibromo-2,3-dihydrobenzofuran (eq 3). Bromoadamantanes and l-bromobicyclo[3.3.1]nonan-3-one undergo fluorination with AgF to yield bridgehead fluorine derivatives (eq 4). 

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