Silver fluoride, as fluorinating

Other addition/elimination sequence was utilized for monofluorination of benzofuran and its derivatives. Thus, the reaction of benzofuran 11 with trifluoromethyl hypofluorite (CF3OF) furnished 2-fluoro-3-trifluoromethoxy-2,3-dihydrobenzofurans 16 (43 % cis- and 15 % franx-isomer) and dx-difluoroderivative 17 (19 %). Treatment of the derivative 17 with ethanohc potassium hydroxide produced 3-fluorobenzofuran 18 in 61 % yield [20], 3-Fluorobenzofuran 18 was also synthesized from the compound 19 using silver fluoride as fluorinating and dehydrohalogenating reagent at the second step [21],... 

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