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Nickel-catalyzed oxidative C-H/N-H annulation of N-heteroaromatic compounds with alkynes.

ABSTRACT: The reaction of N-heteroaromatic compounds, such as 2-aryl-pyrrole, benzimidazole, imidazole, indole, and pyrazole derivatives, with alkynes in the presence of a catalytic amount of a nickel complex results in C-H/N-H oxidative annulation. The reaction shows a high functional group compatibility. While both Ni(0) and Ni(ii) complexes show a high catalytic activity, Ni(0) is proposed as a key catalytic species in the main catalytic cycle. In the case of the Ni(ii) system, the presence of a catalytic amount of a strong base, such as KOBu ^t , is required for the reaction to proceed. In sharp contrast, a base is not required in the case of the Ni(0) system. The proposed mechanism is supported by DFT studies.

SUBMITTER: Obata A

PROVIDER: S-EPMC6430018 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Nickel-catalyzed oxidative C-H/N-H annulation of <i>N</i>-heteroaromatic compounds with alkynes.

Obata Atsushi A Sasagawa Akane A Yamazaki Ken K Ano Yusuke Y Chatani Naoto N

Chemical science 20190204 11

The reaction of N-heteroaromatic compounds, such as 2-aryl-pyrrole, benzimidazole, imidazole, indole, and pyrazole derivatives, with alkynes in the presence of a catalytic amount of a nickel complex results in C-H/N-H oxidative annulation. The reaction shows a high functional group compatibility. While both Ni(0) and Ni(ii) complexes show a high catalytic activity, Ni(0) is proposed as a key catalytic species in the main catalytic cycle. In the case of the Ni(ii) system, the presence of a cataly ...[more]

PMID: 30996908

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