CO in dichloromethane Cooling (-78°C) of solns. of CpFeCO(P(OPh)3)(η1-(E)-C(Me)C(CHMe2)SPh) and (Cp2Fe)(BF4), stirring (20 min, CO, 1 atm), addn. of (Cp2Fe)(BF4) soln. to iron complex by CO-pressure, stirring (45 min), removing from cold bath, stirring (1 h).; Chromy. (Al2O3, hexane/CH2Cl2) yields first ferrocene and orange oils as 4:1 mixts. of diastereomers, elem. anal.;