Copper-Catalyzed Carboxylation of Hydroborated Disustituted Alkenes and Terminal Alkynes with Cesium Fluoride

Martin Juhl, Simon Laursen, Yuxing Huang, Dennis Ulsøe Nielsen, Kim Daasbjerg, Troels Skrydstrup

A protocol for the hydrocarboxylation of disubstituted alkenes and terminal alkynes providing access to different secondary carboxylic acids and malonic acid derivatives has been developed. This methodology relies on an initial hydroboration using 9-BBN followed by carboxylation with carbon dioxide in the presence of a copper catalyst and the additive, cesium fluoride. Different cyclohexene, styrene, and stilbene derivatives could be utilized, and alkynes could be transformed into their corresponding dicarboxylic acids in good yields. Finally, six different terpenoids were carboxylated using the developed procedure.