CO in dichloromethane Cooling (-78°C) of solns. of (CpFeCO(POPh)3)(η1-C(CH2OMe)CMe2) and (Cp2Fe)(BF4), stirring (20 min, CO, 1 atm), addn. of (Cp2Fe)(BF4) soln. to alkenyliron complex by CO-pressure, stirring (45 min), removing from cold bath, stirring (1 h).; Filtering through Al2O3 , evapn. yields yellow-brown oil, yellow oil, chromy. of oil on Al2O3 (eluant: hexane/CH2Cl2) yields ferrocene as first band and light yellow oil, elem. anal.;