A diastereoconvergent approach to (–)‐paroxetine from diastereomeric 3,4‐epoxy‐2‐piperidones is reported. For this synthesis, a regioselective and stereodivergent CuI‐catalyzed epoxide‐ring‐opening reaction of epoxyamide precursors to give the 4‐(4‐fluorophenyl)‐2‐piperidone skeleton with the correct absolute configuration is crucial. Using CuBr·SMe2 as a catalyst, the epoxide‐ring‐opening reaction takes place with inversion of configuration; the configuration is retained when CuI is used.