aluminum chloride; carbon monoxide in dichloromethane addn. of exo-/endo-Fe-complex (1:1) to a suspension of AlCl3 in CH2Cl2 (double equimolar amount), stirred under CO for 20 h, pouring on ice under Ar, further products; repeated extn. (diethyl ether), dried (Na2SO4), evapn. in vac., chromy (silica gel), with diethyl ether: products as fractions a-c;