Synthesis of carbazoles and 1,2-dihydrocarbazoles by domino ‘twofold Heck/6π-electrocyclization’ reactions of di-, tri- and tetrabromoindoles

Hussain, Munawar; Toguem, Serge‐Mitherand Tengho; Rostami, A.; Tùng, Đǎng Thanh; Knepper, Ingo; Villinger, Alexander; Langer, Peter

doi:10.1016/j.tet.2011.05.014

Cited by 31 publications

(10 citation statements)

References 28 publications

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“…Scheme 63 Reaction of a substituted 3-vinylindole 1,2-Dihydrocarbazole derivatives 161 were formed by a domino double Heck coupling/6-electrocyclization from di-, tri-, and tetrabromo-N-methylindoles 159 and acrylates 160 (Scheme 62; see also Section 2.1, Scheme 11 14 ). 65 Under the same reaction conditions, acrylonitrile furnished the unexpected carbazole 162 in 49% yield. This is explained by base-mediated addition of acrylonitrile to the dihydro intermediate formed after electrocyclization; final elimination of HCN provides the carbazole 162.…”

Section: Review Synthesismentioning

confidence: 92%

Pd-Catalyzed Domino Reactions Involving Alkenes To Access Substituted Indole Derivatives

et al. 2020

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Palladium-catalyzed domino reactions are advanced tools in achieving various nitrogen-containing heterocycles in an efficient and economical manner due to the reduced number of steps in the process. This review highlights recent advances in domino processes aimed at the synthesis of indole derivatives and polycyclic systems containing the indole nucleus in intra/intra- or intra/intermolecular reactions. In particular, we consider domino processes that involve a double bond in a step of the sequence, which allow the issue of regioselectivity in the cyclization to be faced and overcome. The different sections in this review focus on the synthesis of the indole nucleus and functionalization of the scaffold starting from different substrates that have been identified as activated starting materials, which involve a halogenated moiety or unactivated unsaturated systems. In the former case, the reaction is under Pd(0) catalysis, and in the second case a Pd(II) catalytic species is required and then an oxidant is necessary to reconvert the Pd(0) into the active Pd(II) species. On the other hand, the second method has the advantage that it uses easy available and inexpensive substrates.1 Introduction2 Indole Scaffold Synthesis2.1 Activated Substrates2.2 Unactivated Substrates3 Functionalization of Indole Scaffold3.1 Activated Substrates3.2 Unactivated Substrates4 Conclusions

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Section: Review Synthesismentioning

confidence: 92%

Pd-Catalyzed Domino Reactions Involving Alkenes To Access Substituted Indole Derivatives

et al. 2020

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“…For industrial applications of carbazole-containing compounds, see: Zhang et al (1998). For pharmaceutical properties of carbazoles, see: Liu & Larock (2007); Hussain et al (2011); Zhang et al (2010); Conchon et al (2006). For a related structure, see: Xie et al (2012).…”

Section: Related Literaturementioning

confidence: 99%

“…Moreover, several alkaloids based on a carbazole structure are known to possess interesting biological activities such as antitumor, antibacterial, antiinflammatory, psychotropic and anti-histamine properties (Liu & Larock, 2007). Many synthetic carbazole derivatives are of significant pharmacological relevance because of their antifungal, antibiotic, and antitumor activities (Hussain et al, 2011;Zhang et al, 2010;Conchon et al, 2006). The introduction of functional groups onto the carbazole scaffold is essential to generate compounds suitable for biological and physical investigations.…”

Section: S1 Commentmentioning

confidence: 99%

3,6-Dichloro-9-(prop-2-yn-1-yl)-9H-carbazole

et al. 2013

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The tricyclic aromatic ring system of the title compound, C15H9Cl2N, is essentially planar (r.m.s. deviation = 0.002 Å). The two Cl atoms lie slightly out of the plane of the carbazole ring system, with the C—Cl bonds forming angles of 1.23 (8) and 1.14 (8)° with the plane. The acetylene group has a syn orientation with respect to the ring system. In the crystal, no weak hydrogen bonds nor any π–π stacking interactions are observed.

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“…The synthesis and functionalization of indoles have been the object of research for over one and a half century (Shiri, 2012). Few examples of Sonogashira-type reactions on the indole core have been described (Hussain et al, 2011;Prateeptongkum et al, 2010).…”

Section: D-mentioning

confidence: 99%

1-Ethyl-2-phenyl-3-[2-(trimethylsilyl)ethynyl]-1H-indole

Baglai¹,

Maraval²,

Duhayon³

et al. 2013

Acta Cryst E

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The title compound, C21H23NSi, was synthesized by Sonogashira-type reaction of 1-ethyl-3-iodo-2-phenyl-1H-indole with trimethylsilylacetylene. The indole ring system is nearly planar [maximum atomic deviation = 0.0244 (15) Å] and is oriented at a dihedral angle of 51.48 (4)° with respect to the phenyl ring. The supramolecular aggregation is completed by weak C—H⋯π interactions of the methylene and phenyl groups with the benzene and pyrrole rings of the indole ring system. The methyl groups of the trimethylsilyl unit are equally disordered over two sets of sites.

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Synthesis of carbazoles and 1,2-dihydrocarbazoles by domino ‘twofold Heck/6π-electrocyclization’ reactions of di-, tri- and tetrabromoindoles

Cited by 31 publications

References 28 publications

Pd-Catalyzed Domino Reactions Involving Alkenes To Access Substituted Indole Derivatives

Pd-Catalyzed Domino Reactions Involving Alkenes To Access Substituted Indole Derivatives

3,6-Dichloro-9-(prop-2-yn-1-yl)-9H-carbazole

1-Ethyl-2-phenyl-3-[2-(trimethylsilyl)ethynyl]-1H-indole

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