Reactions of potassium iron carbonylate with Olefins and alkyl halides

Potassium iron carbonylate, KHFe(CO)(4), reacted with ethyl acrylate, crotonate, 3-butenoate, styrene, and alpha-olefins at 40-70 degrees C under an atmosphere of carbon monoxide. Methylmalonate was selectively obtained from the acrylate by treatment of the reaction mixture with an alcoholic iodine and hydrogen chloride solutions. Dipotassium. iron carbonylate, K,Fe(CO), reacted with beta-bromopropionate to give mainly methylmalonate. Isomerization of beta-ethoxycarbonylpropionyliron carbonylate to the a-isomer occurred readily in contrast to isomerization of acylcobalt carbonyl. Both crotonate and 3-butenoate gave ethylmalonate as a major product and methylsuccinate and glutarate as minor ones. The results suggest that alpha-ethoxycarbonylbutyliron carbonylate is more predominant than the corresponding beta- and gamma-isomers in equilibrium state. This is in strikina contrast to the case of acylcobalt carbonyl. Styrene yielded two isomeric aldehydes, alpha- and beta- phenylpropionalclehydes. Ethyl caproate and enanthate were obtained from I-pentene and 1-hexene, respectively in poor yield.