The mild phase transfer syntheses of the ylide adduct (CO)4[formula omitted]eCH2[formula omitted]Ph3, the octacarbonyl(μ-methylene)diiron μ-CH2Fe2(CO)8, and acyl tetracarbonyliron anions RCOFe(CO)4− are consistent with the transient generation of the Fe(CO)42− dianion from Fe(CO)5

Abstract

Listen

Translate article

Addition of Fe(CO)5 under a nitrogen or carbon monoxide atmosphere to the CH2XY/H2O phase transfer system (X, Y  CL, Br; 1 M NaOH and Bu4N+ HSO4− added) after prior introduction of PPh3, yields the ylide adduct (CO)4F−eCH2P+Ph3 efficiently. In the absence of PPh3, (X  Br, Y  Cl, Br) the methylene bridged complex μ-CH2Fe2(CO)8 is obtained in high yields. In the presence reactive chlorides RCl (R  CH2C6H5, CH2CO2-t-Bu, CH2CN, CH2CHCHC6H5) under CO pressure (10 atm) (X  Y  Cl), the acyltetracarbonyl iron anions RCOFe(CO)4− were obtaiend as tetrabutylammonium salts (soluble in the organic solvent) in high yields. When Fe(CO)5 was replaced by the HFe(CO)4− anion there was no reaction, whereas the products mentioned were formed after introduction of the preformed dianion Fe(CO)42− into the PT system.