34943-91-4Relevant articles and documents
Fenton chemistry enables the catalytic oxidative rearrangement of indoles using hydrogen peroxide
Zhao, Guodong,Liang, Lixin,Wang, Eryu,Lou, Shaoyan,Qi, Rui,Tong, Rongbiao
, p. 2300 - 2307 (2021)
Oxidative rearrangement of indoles is an important transformation to yield 2-oxindoles and spirooxindoles, which are present in many pharmaceutical agents and bioactive natural products. Previous oxidation methods show either broad applicability or greenness but rarely achieve both. Reported is the discovery of Fenton chemistry-enabled green catalytic oxidative rearrangement of indoles, which has wide substrate scope (42 examples) and greenness (water as the only stoichiometric byproduct) at the same time. Detailed mechanistic studies revealed that the Fenton chemistry generated hydroxyl radicals that further oxidize bromide to reactive brominating species (RBS: bromine or hypobromous acid). Thisin situgenerated RBS is the real catalyst for the oxidative rearrangement. Importantly, the RBS is generated under neutral conditions, which addresses a long-lasting problem of many haloperoxidase mimics that require a strong acid for the oxidation of bromide with hydrogen peroxide. It is expected that this new catalytic Fenton-halide system will find wide applications in organic synthesis.
Reactions of 5-aryloxazolidines with CH-acidic compounds
Smorodina, Anastasia A.,Buev, Evgeny M.,Moshkin, Vladimir S.,Sosnovskikh, Vyacheslav Y.
, p. 1620 - 1623 (2019)
5-Aryloxazolidines react with active methylene compounds in the presence of catalytic magnesium ethoxide to give methylene-linked 1,3-dicarbonyl compounds, while the similar reaction with 2-oxindoles results in 3-methyl derivatives.
Green method for preparing oxindole derivative
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Paragraph 0060-0062, (2021/06/26)
The invention relates to the technical field of green organic synthesis, and provides a green method for preparing oxindole derivatives, which comprises the following steps: taking indole compounds with different functional groups as raw materials, under the conditions of room temperature, opening and neutral, adopting MBrx (M is Fe,Fe,Ce and the like) as a catalyst with X equal to 2 or 3, and adopting hydrogen peroxide as a sole oxidant to generate active bromine (RBS) in situ, and catalytically synthesizing the oxindole derivative. According to the method disclosed by the invention, MBrx (such as FeBr2, CeBr3 and the like) is used as the catalyst, so that an expensive or complex catalyst is avoided, and the method is green, environment-friendly, safe, simple, efficient, mild in reaction condition and wide in substrate application range, has a relatively good application prospect and is expected to be widely applied to organic synthesis, fine chemical engineering and pharmaceutical industry.
Iron-Catalyzed Reductive Cyclization by Hydromagnesiation: A Modular Strategy Towards N-Heterocycles
Larin, Egor M.,Lautens, Mark,Loup, Joachim
supporting information, p. 22345 - 22351 (2021/09/09)
A reductive cyclization to prepare a variety of N-heterocycles, through the use of ortho-vinylanilides, is reported. The reaction is catalyzed by an inexpensive and bench-stable iron complex and generally occurs at ambient temperature. The transformation likely proceeds through hydromagnesiation of the vinyl group, and trapping of the in situ generated benzylic anion by an intramolecular electrophile to form the heterocycle. This iron-catalyzed strategy was shown to be broadly applicable and was utilized in the synthesis of substituted indoles, oxindoles and tetrahydrobenzoazepinoindolone derivatives. Mechanistic studies indicated that the reversibility of the hydride transfer step depends on the reactivity of the tethered electrophile. The synthetic utility of our approach was further demonstrated by the formal synthesis of a reported bioactive compound and a family of natural products.
