To a stirred and refluxing Grignard-complex, previously prepared starting from 70 parts of 1-bromo-4-fluorobenzene and 10 parts of magnesium in 270 parts of tetrahydrofuran, was added dropwise a solution of 25 parts of ethyl 1-(phenylmethyl)-4-piperidinecarboxylate in 90 parts of tetrahydrofuran. Upon completion, stirring was continued for 2 hours at reflux temperature. The reaction mixture was cooled and poured onto a saturate ammonium chloride solution. The organic phase was separated, dried, filtered and evaporated, yielding 40 parts of α,α-bis(4-fluorophenyl)-1-(phenylmethyl)-4-piperidinemethanol as a residue (intermediate 12).
