aluminium trichloride in dichloromethane byproducts: (C5H5)Fe(C5H3(COMe)2); (N2); AlCl3 is added to mixt. of iron-complex and acetyl chloride in CH2Cl2 at -42°C, stirring for 75 min; mixt. is poured into ice water, aq. phase is extd. with CH2Cl2, combined extracts are dried (Na2SO4) and concd., chromy. (SiO2, hexane/EtOAc);