Organocatalytic asymmetric Michael addition of 2-naphthols to alkylideneindolenines generated in situ from arenesulfonylalkylindoles

Yu, Liangliang; Xie, Xiaohua; Wu, Song; Wang, Rongming; He, Wei; Qin, Da‐Bin; Liu, Quanzhong; Jing, Lin‐Hai

doi:10.1016/j.tetlet.2013.05.011

Cited by 30 publications

(15 citation statements)

References 68 publications

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“…Yu et al found the diastereomer 44b of catalyst 44a to be the most effective catalyst for the Michael addition of 2-naphthols to alkylidene-indolinine intermediates, generated in situ from arenesulfonylalkylindoles, yielding the corresponding adducts as a series of optically active C3 alkyl-substituted indole derivatives containing phenolic hydroxyl groups. 44 Zhao et al developed the cinchonidine-derived thiourea 40b-catalyzed asymmetric Michael addition of 3-substituted-N-Boc-oxindoles 59 to a vinyl bisphosphonate 60, affording the corresponding adducts 61 (Figure 21) bearing a quaternary carbon stereocenter and germinal bisphosphonate ester fragment at the C3 position of the oxindoles. 45 In the plausible transition-state model, substrate 59 would be activated by tertiary amine thiourea in bifunctional mode, and the enolized oxindoles would attack the vinyl bisphosphonates from the Si face to give the corresponding adducts with R-configuration.…”

Section: Application Of C9 Thioureasmentioning

confidence: 99%

Recent applications of <em>Cinchona</em> alkaloid-based catalysts in asymmetric addition reactions

Singh¹,

Yeboah²

2016

ROC

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This review documents recently developed asymmetric addition reactions catalyzed by natural Cinchona alkaloids and their derivatives. These reactions include direct nucleophilic additions across the carbon-oxygen double bond and the carbon-nitrogen double bond, 1,4-additions, and cycloadditions. Natural and modified Cinchona alkaloids with different functionalities, such as amino, alkoxy, hydroxyl, amido, urea, and thiourea, especially on position C9, have been employed as catalysts in these reactions. Mechanistic considerations are discussed in many cases. In some cases, the application of adducts in further synthesis is also described.

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Section: Application Of C9 Thioureasmentioning

confidence: 99%

Recent applications of <em>Cinchona</em> alkaloid-based catalysts in asymmetric addition reactions

Singh¹,

Yeboah²

2016

ROC

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“…On the other hand, this effect is identical to what we observed in the organocatalyzed reaction of sulfonyl indoles with aldehydes in the absence of any substituent at the 2‐position of the indole ring. 2‐Naphthols behave as effective enols in enantioselective organocatalyzed reactions with sulfonyl indoles 61. The process is highly regioselective, since only the 1‐position of the naphthol ring is reactive toward the alkylideneindolenine intermediate.…”

Section: Reaction With Enolate Systemsmentioning

confidence: 99%

Sulfonyl Azoles in the Synthesis of 3-Functionalized Azole Derivatives

Palmieri

Petrini

2016

The Chemical Record

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Sulfonyl indoles, as well as related azolyl derivatives, have been recently introduced in synthesis as stable precursors of reactive indolenine intermediates. This personal account reports on the discovery of sulfonyl azoles and their practical utilization in many synthetic processes for the preparation of functionalized 3-substituted indoles, indazoles, and pyrroles. The indolenine intermediates obtained by treatment of sulfonyl azoles with Brønsted bases or Lewis acids can be considered as vinylogous imino derivatives that can be made to react with different nucleophilic reagents. These include organometallic reagents, reducing agents, stabilized carbanions, and heteronucleophiles. The controlled and mild conditions for the generation of indolenines from sulfonyl azoles make these substrates particularly useful in asymmetric synthesis, exploiting organo- or metal-catalyzed processes. Although less exploited, sulfonyl indoles can also be involved in photochemical processes for the preparation of polycyclic derivatives.

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“…2‐Naphthols 126 served as the nucleophiles to construct C3‐alkyl‐substituted indole derivatives 127 containing phenolic hydroxyl groups in high yields (up to 96 %) and enantioselectivity (up to 98 % ee ) under mild conditions with 20 as catalysts in 2012 (Scheme ) 42. The position of R 3 substituent in 126 has a significant influence on the enantioselectivity of the reaction and a meta substituent seems to be more beneficial than para substituent.…”

Section: Generation From Cs Bond Cleavage: Toluenesulfonyl As Thementioning

confidence: 99%

Alkylideneindoleninium Ions and Alkylideneindolenines: Key Intermediates for the Asymmetric Synthesis of 3‐Indolyl Derivatives

2014

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Alkylideneindoleninium ions and alkylideneindolenines generated from 3-substituted indoles are important intermediates in organic synthesis, which can be trapped by a large variety of nucleophilic reagents to construct biologically important 3-indolyl derivatives. This Focus Review summarizes the recent developments in asymmetric syntheses of 3-indolyl derivatives via alkylideneindoleninium ions or alkylideneindolenines. The elimination mechanism of leaving groups and asymmetric strategies are discussed.

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Organocatalytic asymmetric Michael addition of 2-naphthols to alkylideneindolenines generated in situ from arenesulfonylalkylindoles

Cited by 30 publications

References 68 publications

Recent applications of <em>Cinchona</em> alkaloid-based catalysts in asymmetric addition reactions

Recent applications of <em>Cinchona</em> alkaloid-based catalysts in asymmetric addition reactions

Sulfonyl Azoles in the Synthesis of 3-Functionalized Azole Derivatives

Alkylideneindoleninium Ions and Alkylideneindolenines: Key Intermediates for the Asymmetric Synthesis of 3‐Indolyl Derivatives

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