Question

Write the reaction of metal carbonyl with alkyl halides

Answer 1

Mono- and di-substituted derivatives of iron pentacarbonyl react with alkyl halides and polyhalides through two parallel paths, one radical and the other molecular. Only in two cases could the two mechanisms be isolated and studied separately. The reaction between Fe(CO)3(AsPh3)2 and CCl4 to give Fe(CO)2- (AsPh3)2Cl2 is radical and affected by light and duroquinone. The proposed mechanism is similar to that of the reaction between Fe(CO)3L2 and halogens. The reaction between Fe(CO)3(PMe3)2 and MeI to form Fe(CO)2(PMe3)2(COMe)I is first order in both reactants, and free CO or P(Me)4I has no effect on the rate. The kinetics are interpreted in term of a concerted nucleophilic displacement involving formation of anionic intermediate