Selective Electrosynthetic Hydrocarboxylation of α,β‐Unsaturated Esters with Carbon Dioxide

• Published in: Angewandte Chemie International Edition Vol. 60; no. 40; pp. 21832 - 21837
• Main Authors: Sheta, Ahmed M., Alkayal, Anas, Mashaly, Mohammad A., Said, Samy B., Elmorsy, Saad S., Malkov, Andrei V., Buckley, Benjamin R.
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 27.09.2021; Wiley Subscription Services, Inc; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: acrylate; Alkenes; Carbon dioxide; Carbon monoxide; Carboxylation; Carboxylic acids; Catalysts; Chemical reduction; Chemistry; Chemistry, Multidisciplinary; Crystallization; Electrochemistry; electron transfer; Esters; Photochemicals; Physical Sciences; Reagents; reduction; Regioselectivity; Science & Technology; Selectivity; Substrates; Transition metals; carbon dioxide; STYRENES; electrochemistry; CO2; ELECTROCHEMICAL REDUCTION; ENANTIOSELECTIVE CONSTRUCTION; FLOW; acrylate; CARBONYLATION; electron transfer; CARBOXYLATION; reduction; ELECTROCARBOXYLATION
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202105490

The carboxylation of low‐value commodity chemicals to provide higher‐value carboxylic acids is of significant interest. Recently alternative routes to the traditional hydroformylation processes that used potentially toxic carbon monoxide and a transition metal catalyst have appeared. A significant challenge has been the selectivity observed for olefin carboxylation. Photochemical methods have shown a viable route towards the hydrocarboxylation of α,β‐unsaturated alkenes but rely on the use of an excess reducing or amine reagent. Herein we report our investigations of an electrochemical approach that is able to hydrocarboxylate α,β‐unsaturated alkenes with excellent regioselectivity and the ability to carboxylate hindered substrates to afford α‐quaternary center carboxylic acids. The reported process requires no chromatography and the products are purified by simple crystallization from the reaction mixture after work‐up. Electrosynthetic hydrocarboxylation of α,β‐unsaturated olefins with excellent regioselectivity is reported. The method requires no sacrificial electrode and is thus amenable to a flow configuration. The products are purified by simple crystallization. The synthesis of a precursor to ethosuximide, which contains an all‐carbon quaternary center, illustrates the potential of the process. Finally, a robustness study has benchmarked the process for future users.