Reductive carboxylation of organo (pseudo)halides with CO 2 is ap owerfulm ethod to providec arboxylic acids quickly.Notably,the catalytic reductive carbo-carboxylation of unsaturated hydrocarbons via CO 2 fixation is ah ighly challenging but desirable approach for structurally diverse carboxylic acids.T here are only af ew reports and no examples of alkenes via transition metal catalysis.W er eport the first asymmetric reductive carbo-carboxylation of alkenes with CO 2 via nickel catalysis.Avariety of aryl (pseudo)halides,s uch as aryl bromides,a ryl triflates and inert aryl chlorides of particular note,u ndergo the reaction smoothly to give important oxindole-3-acetic acid derivatives bearing aC3-quaternary stereocenter.T his transformation features mild reaction conditions,w ide substrate scope,f acile scalability,g ood to excellent chemo-, regio-and enantioselectivities.T he method highlights the formal synthesis of (À)-Esermethole, (À)-Physostigmine and (À)-Physovenine,a nd the total synthesis of (À)-Debromoflustramide B, (À)-Debromoflustramine Ba nd (+ +)-Coixspirolactam A; thereby, opening an avenue for the total synthesis of chiral natural products with CO 2 .

An effective Cu-catalyzed selective formal carboxylation of C–F bonds with an atmospheric pressure of CO2 is reported. A variety of gem-difluoroalkenes, gem-difluorodienes, and α-trifluoro-methyl alkenes show high reactivity and selectivity for this ipso monocarboxylation. Under mild conditions, diverse important α-fluoroacrylic acids and α,α-difluorocarboxylates are obtained in good-to-high yields. Moreover, this operationally simple protocol features good functional group tolerance, is readily scalable, and the resulting products are readily converted into bioactive α-fluorinated carbonyl compounds, indicating potential application in biochemistry and drug discovery. Mechanistic studies reveal that fluorinated boronate esters might be vital intermediates in this transformation.

Diacids are important monomers in the polymer industry to construct valuable materials. Dicarboxylation of unsaturated bonds, such as alkenes and alkynes, with CO2 has been demonstrated as a promising synthetic method. However, dicarboxylation of CC single bonds with CO2 has rarely been investigated. Herein we report a novel electrochemical ring-opening dicarboxylation of CC single bonds in strained rings with CO2. Structurally diverse glutaric acid and adipic acid derivatives were synthesized from substituted cyclopropanes and cyclobutanes in moderate to high yields. In contrast to oxidative ring openings, this is also the first realization of an electroreductive ring-opening reaction of strained rings, including commercialized ones. Control experiments suggested that radical anions and carbanions might be the key intermediates in this reaction. Moreover, this process features high step and atom economy, mild reaction conditions (1 atm, room temperature), good chemoselectivity and functional group tolerance, low electrolyte concentration, and easy derivatization of the products. Furthermore, we conducted polymerization of the corresponding diesters with diols to obtain a potential UV-shielding material with a self-healing function and a fluorine-containing polyester, whose performance tests showed promising applications.

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