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.
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http://dx.doi.org/10.1002/anie.202105490 | DOI Listing |
Chemistry
December 2024
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200062, China.
Pd-catalyzed alkoxycarbonylation of internal alkynes provides a straightforward access to α,β-disubstituted acrylic esters. Compared with the well-established regioselective alkoxycarbonylation of terminal alkynes, the regioselective hydrocarboxylation of non-functionalized unsymmetric internal alkynes was more challenging owing to the delicate differences of properties between the two substituents. Herein, by using either monophosphine ligand based on 2,3-dihydrobenzo[d][1,3]oxaphosphole motif or bidentate ligand Ph-Phox, the regioselective alkoxycarbonylations of aryl-aryl, aryl-alkyl and alkyl-alkyl disubstituted alkynes were achieved, giving a diversity of trisubstituted α,β-unsaturated carboxylic esters with moderate to excellent yields and high regioselectivity.
View Article and Find Full Text PDFNat Commun
November 2024
Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, India.
Precis Chem
March 2024
Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University, Kita 21, Nishi 10, Kita-ku, Sapporo, Hokkaido 001-0021, Japan.
γ-Butyrolactone structures are commonly found in various natural products and serve as crucial building blocks in organic synthesis. Consequently, the development of methods for synthesizing γ-butyrolactones has garnered significant interest within the organic synthesis community. In this study, we present a direct and highly efficient approach for the synthesis of γ-butyrolactones from allylic alcohols.
View Article and Find Full Text PDFJ Am Chem Soc
November 2024
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India.
The direct utilization of carbon dioxide as an ideal one-carbon source in value-added chemical synthesis has garnered significant attention from the standpoint of global sustainability. In this regard, the photo/electrochemical reduction of CO into useful fuels and chemical feedstocks could offer a great promise for the transition to a carbon-neutral economy. However, challenges in product selectivity continue to limit the practical application of these systems.
View Article and Find Full Text PDFAn unprecedented and highly reactive Pd/C catalytic system has been introduced for the regiodivergent hydrocarboxylation of terminal alkynes to selectively afford various acrylic and cinnamic acids employing oxalic acid as a CO source as well as a promoter for the formation of the active Pd-H complex. Herein, the formation of cinnamic acid is proposed to follow a unique anti-Markovnikov hydroiodination mechanism and the formation of acrylic acid might follow the traditional hydrocarboxylation pathway. Additionally, internal alkynes undergo hydrocarboxylation and carbonylative esterification with aliphatic alcohols to yield different α,β-unsaturated acids and esters respectively.
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