Palladium-Catalyzed Intramolecular Arylative Carboxylation of Allenes with CO2 for the Construction of 3-Substituted Indole-2-carboxylic Acids
Yuki Higuchi, Tsuyoshi Mita* and Yoshihiro Sato*
*Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan, Email: tmitapharm.hokudai.ac.jp, biyopharm.hokudai.ac.jp
Y. Higuchi, T. Mita, Y. Sato, Org. Lett., 2017, 19, 2710-2713.
DOI: 10.1021/acs.orglett.7b01055 (free Supporting Information)
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A Pd-catalyzed arylative carboxylation of allenes proceeded in an intramolecular manner to afford the corresponding β,γ-unsaturated carboxylic acids in high yields in the presence of ZnEt2 under 1 atm of CO2. The obtained products could be efficiently converted into 3-substituted indole-2-carboxylate derivatives.
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derivatization of carboxylated compound 2a into 3-substituted indole-2-carboxylates and 3-oxindole-2-carboxylate