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DOI: 10.1055/a-1516-7960
C(sp3)–H Activation Enabled by (η3-Indolylmethyl)palladium Complexes: Synthesis of Monosubstituted Tetrahydrocarbazoles
We thank IISER Mohali for the financial support. S.S.V.R. thanks DST for the Swarnajayanti fellowship (DST/SJF/CSA-01/2017-18), SERB for the Core Research Grant (CRG/2018/000016), and the Royal Society of Chemistry for the ‘RSC Research Fund’ grant (R20-3255).
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Abstract
The synthesis of monosubstituted tetrahydrocarbazoles is achieved via the palladium-catalyzed formal [4+2] cycloaddition of 2-alkyl-3-indolylmethyl carbonates and monosubstituted olefins. The transformation demonstrates an unusual C(sp3)–H activation enabled by (η3-indolylmethyl)palladium complexes. The regioselectivity is found to be dependent on the nature of the substituent across the olefin component. Elaborate mechanistic studies are performed, and the synthetic utility of the products is also demonstrated.
Key words
C–H functionalization - tetrahydrocarbazoles - [4+2] cycloaddition - annulation - C–C bond formationSupporting Information
- Supporting information for this article is available online at https://doi.org/10.1055/a-1516-7960.
- Supporting Information
- CIF File
Publication History
Received: 25 April 2021
Accepted after revision: 25 May 2021
Accepted Manuscript online:
25 May 2021
Article published online:
24 June 2021
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Recent comprehensive reviews on THCs:
Some selected references:
For η3-indolylmethyl palladium complexes, see:
Recent reviews on benzyl π-allylpalladiums:
The [4+2] cycloaddition of heteroaryl-based o-QDMs generated in situ by flash vacuum pyrolysis (FVP) of similar substrates are well known. For example, see: