Wani, Imtiyaz Ahmad ; Bhattacharyya, Aditya ; Sayyad, Masthanvali ; Ghorai, Manas K. (2018) Temperature-modulated diastereoselective transformations of 2-vinylindoles to tetrahydrocarbazoles and tetrahydrocycloheptadiindoles Organic & Biomolecular Chemistry, 16 (16). pp. 2910-2922. ISSN 1477-0520
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Official URL: http://doi.org/10.1039/C8OB00228B
Related URL: http://dx.doi.org/10.1039/C8OB00228B
Abstract
Direct and expedient access to densely substituted tetrahydrocarbazoles and tetrahydrocycloheptadiindoles bearing multiple contiguous stereocentres has been achieved via a two-fold divergent diastereoselective (dr up to >99 : 1) transformation of 2-vinylindoles. The high-yielding conversions (yield up to 87%) that are amenable for a wide range of substituted 2-vinylindoles proceed through Lewis acid-catalyzed [4 + 2] and [4 + 3] cyclization–aromatization cascade reactions, respectively, involving a heretofore-unprecedented reversal of the polarity (umpolung) of 2-vinylindoles. The two synthetic routes are effortlessly transposable into each other by merely modulating the temperature to furnish the corresponding products in a selective and exclusive fashion. In addition, another novel synthetic route to tetrahydroindolocarbazoles has been developed that advances via a formal [4 + 2] cyclization of 4-vinylindoles involving sequential C3 Michael addition–dearomatization–aromatization cascade reactions.
Item Type: | Article |
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Source: | Copyright of this article belongs to Royal Society of Chemistry. |
ID Code: | 117087 |
Deposited On: | 15 Apr 2021 07:43 |
Last Modified: | 15 Apr 2021 07:43 |
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