in tetrahydrofuran 8 ml THF was condensed onto a solid mixture of {{C5H5(CO)Fe}2(μ-CO)(μ-CHCO)}PF6 and Et4N{HFe(CO)4} at -78°C, stirred at -78°C for 90 min, evapn. of solvent, residue extracted into CH2Cl2;; chromy. (Al2O3, hexane/Et2O=1:1) giving {C5H5(CO)Fe}2(CO)(CH2), chromy. (acetone/Et2O=1:1) giving mixt. of NEt4PF6 and {C5H5(CO)Fe}2(CO)(CHCHO), extn. into Et2O, filtration through Celite, evapn., washing with hexane, drying, elem. anal.;;

carbon monoxide; ethyl iodide in tetrahydrofuran byproducts: ethane; 25°C, 100 psi of CO;