hydrogenchloride in tetrahydrofuran; diethyl ether N2-atmosphere; addn. of 2.5 equiv. BuLi to Fe-complex soln. (in THF/Et2O-1:1) at -70°C, warming to -50°C, treatment with excess CO2, warming to room temp., quenching with H2O, drying (vac.), dissoln. inMeOH, stirring with HCl overnight; dropwise addn. of diltd. NaOH to pH=8, extn. into Et2O, drying (MgSO4), solvent removal (vac.), chromy. (Al2O3);