Photocatalytic PPh 3 -Mediated Synthesis of C3-Functionalized Indoles via Radical Annulation of Nitroarenes and Alkenes.

Autor: Zhang J; Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany., Mück-Lichtenfeld C; Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany.; Center for Multiscale Theory and Computation, Universität Münster, 48149, Münster, Germany., Wiethoff MA; Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany., Studer A; Organisch-Chemisches Institut, Universität Münster, 48149, Münster, Germany.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2024 Dec 09; Vol. 63 (50), pp. e202416726. Date of Electronic Publication: 2024 Oct 31.
DOI: 10.1002/anie.202416726
Abstrakt: Oxidatively generated phosphine radical cations are reactive intermediates that can be used for the generation of carbon and heteroatom centered radicals via deoxygenation processes. Such P-radical cations can readily be generated via single electron transfer oxidation using a redox catalyst. Cheap and commercially available nitroarenes are ideal nitrogen sources for the construction of organic amines and N-containing heterocycles. Activation of nitroarenes with phosphines has been achieved in the ionic mode, which requires specially designed P-nucleophiles and high temperatures. Herein, we report an alternative mode of nitro activation that proceeds via a radical process. The radical strategy leads to open shell intermediates that show interesting unexplored reactivity. This is documented by the development of an economic and highly efficient synthesis of valuable indole derivatives through photocatalytic PPh 3 -mediated annulation of nitroarenes with alkenes showing large functional group tolerance. The method allows room-temperature activation of nitroarenes and a double C-H bond functionalization of alkenes is achieved to provide rapid access to C3-functionalized indoles, which are key structural components of diverse natural and drug molecules. Experimental mechanistic studies that are further supported by DFT calculations indicate that a nitrosoarene radical cation plays a key role in the annulation process.
(© 2024 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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