in diethyl ether (Ar), Fe complex in Et2O treated with methyl oxalyl chloride (1.2 equiv.), stirred for 2 h (protection of light); evapd.(vac.), dissolved (CH2Cl2), chromy.(silica gel -hexane, Et2O:hexane 1:1 v/v), recrystd.(CH2Cl2/hexane), elem. anal.;

in diethyl ether (Ar), Fe complex in Et2O treated with methyl oxalyl chloride (1.2 equiv.), stirred for 2 h (protection of light); evapd.(vac.), dissolved (CH2Cl2), chromy.(silica gel -hexane, Et2O:hexane 1:1 v/v), recrystd.(CH2Cl2/hexane), elem. anal.;

in diethyl ether (Ar), Fe complex in Et2O treated dropwise with oxalyl chloride (0.5 equiv.), stirred for 0.5 h (protection of light); evapd.(vac.), dissolved (CH2Cl2), chromy.(silica gel -hexane, Et2O:hexane 1:1 v/v), recrystd.(CH2Cl2/hexane), elem. anal.;