Carboxylation of Organozinc Reagents Using CO₂ in DMF

Key words

organozinc reagents - carboxylation - carbon dioxide

Significance

This is the first report on the transition-metal-free carboxylation of organozinc compounds. Functionalized alkyl-, alkenyl-, benzylic, and arylzinc compounds prepared by a variety of methods can be involved in this reaction affording good yields of the corresponding acids. This is a simple and useful method for the preparation of functionalized carboxylic acids.

Comment

The carboxylation of PhZnI-LiCl in THF is very sluggish and gives in the absence of LiCl only traces of the product. Electron-­withdrawing groups and steric hindrance slow the reaction down. For a method of palladium-catalyzed carboxylation of organozinc compounds, see: C. S. Yeung, V. M. Dong J. Am. Chem. Soc. 2008, 130, 7826.