magnesium; cobalt(II) chloride in tetrahydrofuran Addn. of Mg to 1-bromo-1'-(1-methyl-2,5-dioxacyclopentyl)ferrocene soln., stirring, addn. of BrCH2CH2Br, after 20 min soln. darkens and evolution of gas is observed, after 3 h cooling (0°C), addn. to CoCl2, white powder pptd., soln. turns green.; After 18 h stirring addn. to acid H2O, stirring overnight, red solid pptd., filtration, extn. of filtrate with ether, evapn, combination with ppt., recrystn. from hot toluene, mother liquors yield acetylferrocene.;

n-butyllithium in diethyl ether Addn. of BuLi to 1-Br-1'-(1-methyl-2,5-dioxacyclopentyl)ferrocene soln. (N2, -78°C), warming to room temp., yellow soln. turns orange, after 15 min orange powder pptd., addn. of 2-cyclopentene-1-one to rapidly stirred suspn., stirring (1 h).; Addn. of H2O, extn. with hexane, drying (MgSO4), evapn., dissolving of residue in acetone, stirring with H2O overnight, extn., chromy. yields acetylferrocene and debrominated ketal.;