Synthesis of Vinyl Carboxylic Acids using Carbon Dioxide as a Carbon Source by Iron‐Catalyzed Hydromagnesiation

An iron-catalyzed synthesis of α,β-unsaturated carboxylic acids from alkynes and carbon dioxide was developed. This reaction proceeds through hydromagnesiation of alkynes followed by carbon dioxide insertion under atmospheric pressure and ambient temperature in the presence of iron and a Grignard reagent as a catalyst and hydride source, respectively. Several symmetrical and unsymmetrical alkynes were transformed into the corresponding acids in good to excellent yields. The methodology provides an efficient route to the synthesis of vinyl carboxylic acids.