New organic synthetic methods using iron carbonyl reagents

Abstract

Investigations carried out on the preparation and synthetic applications of iron carbonyl reagents are reviewed. Reaction of Na2Fe(CO)4, prepared by the reduction of FeCl3 in THF with sodium naphthalenide under CO atmosphere at 25°C, with alkyl bromides gives the corresponding aldehydes, ketones and carboxylic acids under appropriate conditions. Reaction of NaR(CO)Fe(CO)4 with CuCl at 25°C in THF, leads to the formation of 1,2-diketones. However, in the presence of methylacrylate in addition to the 1,2-diketones the corresponding acyllactones are also formed. Mechanistic pathways and intermediates involved are discussed. Reactions of NaHFe(CO)4/RX or [HFe3(CO)11] reagents with alkynes lead to the formation of the corresponding α,β-unsaturated carboxylic acids and/or the cyclobutenediones after CuCl2·2H2O oxidation. Possible intermediates and mechanistic pathways are discussed.