Palladium-Catalyzed Cascade Process Consisting of Isocyanide Insertion and Benzylic C(sp3)-H Activation: Concise Synthesis of Indole Derivatives
Takeshi Nanjo, Chihiro Tsukano and Yoshiji Takemoto*
*Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan, Email: takemotopharm.kyoto-u.ac.jp
T. Nanjo, C. Tsukano, Y. Takemoto, Org. Lett., 2012, 14, 4270-4273.
DOI: 10.1021/ol302035j (free Supporting Information)
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A Pd-catalyzed cascade process consisting of isocyanide insertion and benzylic C(sp3)-H activation allows the construction of the indole skeleton. Slow addition of isocyanide is effective for reducing the amount of catalyst needed and Ad2PBu is a good ligand for C(sp3)-H activation. The construction of the tetracyclic carbazole skeleton was also achieved by a Pd-catalyzed domino reaction incorporating alkyne insertion.
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