Cathodic carbonylation. Synthesis of aliphatic aldehydes using an electroreductively generated iron-carbonyl anion
Alkyl halides are electroreductively coupled with pentacarbonyliron to generate the acyliron complexes. After hydrolytic work-up, these anionic acyl compounds produce aldehydes in good yields. The best results were obtained with the bromide as starting halide. The first step in the formation of acyliron complexes is the direct cathodic reduction of [Fe(CO)5] to the anionic species. Synthetic and mechanistic aspects of the reaction are discussed.