A catalytic hydrogenation over Pd/C would give ethyl 2-[(2-fluorophenyl)methyl]-2-hydroxybutanoate, CID:77591056 (4).

Saponification of the ester then gives 2-[(2-Fluorophenyl)methyl]-2-hydroxybutanoic acid, CID:53869347 (5).

Treatment with 2 molar equivalents of sodium hydride apparently gives 2-Ethyl-2,3-dihydrobenzofuran-2-carboxylic acid [111080-50-3] (6).

Treatment of the carboxylic acid with thionyl chloride then gives the acid chloride and subsequent treatment of this with ethylenediamine in the presence of trimethylaluminium completed the synthesis of Efaroxan (8).

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