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Green oxidation of indoles using halide catalysis.

ABSTRACT: Oxidation of indoles is a fundamental organic transformation to deliver a variety of synthetically and pharmaceutically valuable nitrogen-containing compounds. Prior methods require the use of either organic oxidants (meta-chloroperoxybenzoic acid, N-bromosuccinimide, t-BuOCl) or stoichiometric toxic transition metals [Pb(OAc)4, OsO4, CrO3], which produced oxidant-derived by-products that are harmful to human health, pollute the environment and entail immediate purification. A general catalysis protocol using safer oxidants (H2O2, oxone, O2) is highly desirable. Herein, we report a unified, efficient halide catalysis for three oxidation reactions of indoles using oxone as the terminal oxidant, namely oxidative rearrangement of tetrahydro-?-carbolines, indole oxidation to 2-oxindoles, and Witkop oxidation. This halide catalysis protocol represents a general, green oxidation method and is expected to be used widely due to several advantageous aspects including waste prevention, less hazardous chemical synthesis, and sustainable halide catalysis.

SUBMITTER: Xu J

PROVIDER: S-EPMC6802211 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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Green oxidation of indoles using halide catalysis.

Xu Jun J Liang Lixin L Zheng Haohao H Chi Yonggui Robin YR Tong Rongbiao R

Nature communications 20191018 1

Oxidation of indoles is a fundamental organic transformation to deliver a variety of synthetically and pharmaceutically valuable nitrogen-containing compounds. Prior methods require the use of either organic oxidants (meta-chloroperoxybenzoic acid, N-bromosuccinimide, t-BuOCl) or stoichiometric toxic transition metals [Pb(OAc)4, OsO4, CrO3], which produced oxidant-derived by-products that are harmful to human health, pollute the environment and entail immediate p ...[more]

PMID: 31628334

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