A Facile One‐pot Synthesis of Highly Functionalized Isoxazolyl Imidazo[1,2‐<i>a</i>] Pyridines Through CuI‐Promoted Cyclization

Rajanarendar, E.; Reddy, K. Govardhan; Krishna, S. Rama; Srinivas, M.

doi:10.1002/jhet.2146

Cited by 10 publications

(3 citation statements)

References 28 publications

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“…Although 50% yield of desired product 3 a was obtained for metal catalyst CuCl, poor selectivity results (2:1 dr and 71% ee) were also obtained (Table 1, entry 6). Based on above unsatisfactory results, we also investigated the relevant literatures on the copper‐catalyzed tandem oxidative reactions of 2‐arylindoles [11a–f] and then evaluated the effect of various additives (such as pyridine, Na 2 CO 3 and AcOH) in the presence of catalyst E and metal catalyst CuI (Table 1, entries 11–13). To our delight, this one‐pot asymmetric oxidative dearomative cascade reaction can proceed smoothly and the desired product 3 a was obtained with up to 70% yield, 5:1 dr and 93% ee when pyridine (2.0 equiv.)…”

Section: Resultsmentioning

confidence: 99%

One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones

Zhao

Yang

et al. 2022

Adv Synth Catal

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A one-pot approach for the asymmetric synthesis of C2-tetrasubstituted indolin-3-ones from 2substituted indoles was developed via merging transition metal catalysis with organocatalysis. This strategy involves two processes, including CuI catalyzed oxidative dearomatization of 2-substituted indoles using O 2 as green oxidant, and followed by an proline-promoted asymmetric Mannich reaction with ketones or aldehydes. A series of C2-tetrasubstituted indolin-3-ones were obtained in 35-86% yields, 2:1-> 20:1 dr and 48-99% ee. Moreover, the synthetic 2-tetrasubstituted indolin-3-ones could be easily transformed into 1H-[1,3] oxazino [3,4-a]indol-5(3H)-ones via a [4 + 1] cyclization process. In addition, the synthetic compound 3 s show certain antibacterial activity against S. aureus ATCC25923 and multi-drug resistance bacterial strain of S. aureus (20151027077) and its MIC values up to 8 μg/mL and 16 μg/mL, respectively.

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Section: Resultsmentioning

confidence: 99%

One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones

Zhao

Yang

et al. 2022

Adv Synth Catal

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“…An unprecedented CuI-catalyzed two-component synthesis of isoxazolylimidazo[1,2- a ]pyridines 49 was reported by the group of Rajanarendar under aerial conditions. Differently substituted 2-AP 3 and substituted nitrostyrylisoxazole 48 were used as reaction substrates at 80 °C (Scheme 17) [112]. The method has tolerated a variety of functional groups with good yield.…”

Section: Reviewmentioning

confidence: 99%

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

Reen

Kumar

Sharma

2019

Beilstein J. Org. Chem.

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A comprehensive account of recent advances in the synthesis of imidazopyridines, assisted through transition-metal-catalyzed multicomponent reactions, C–H activation/functionalization and coupling reactions are highlighted in this review article. The basic illustration of this review comprises of schemes with concise account of explanatory text. The schemes depict the reaction conditions along with a quick look into the mechanism involved to render a deep understanding of the catalytic role. At some instances optimizations of certain features have been illustrated through tables, i.e., selectivity of catalyst, loading of the catalyst and percentage yield with different substrates. Each of the reported examples has been rigorously analyzed for reacting substrates, reaction conditions and transition metals used as the catalyst. This review will be helpful to the chemists in understanding the challenges associated with the reported methods as well as the future possibilities, both in the choice of substrates and catalysts. This review would be quite appealing to a wider range of organic chemists in academia and industrial R&D sectors working in the field of heterocyclic syntheses. In a nutshell, this review will be a guiding torch to envisage: (i) the role of various transition metals in the domain dedicated towards method development and (ii) for the modifications needed thereof in the R&D sector.

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“…44 The Rajanarender group reported the onepot synthesis of 3-isoxazol-5-ylimidazo[1,2-a]pyridines via oxidative cyclization of 2-aminopyridines with 4-nitro-5styrylisoxazoles under aerial oxidation conditions; copper(I) iodide efficiently catalyzed the annulation and afforded good yields of 3-isoxazol-5-ylimidazo[1,2-a]pyridines. 45…”

Section: Scheme 13mentioning

confidence: 99%

Recent Developments in the Synthesis of Imidazo[1,2-a]pyridines

Pericherla¹,

Kaswan²,

Pandey³

et al. 2015

Synthesis

186

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N N cyclocondensations oxidative cyclizations multicomponent reactions rearrangements tandem processes C-H activations/functionalizationsAbstract Advances in the last decade for the synthesis of the imidazo[1,2-a]pyridine scaffold from various substrates employing approaches such as multicomponent reactions, tandem processes, rearrangement reactions, inter-and intramolecular oxidative/reductive cyclizations, and transition-metal-catalyzed C-H activation are summarized in this review. The mechanisms for the selected transformations are also discussed. 1

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A Facile One‐pot Synthesis of Highly Functionalized Isoxazolyl Imidazo[1,2‐a] Pyridines Through CuI‐Promoted Cyclization

Cited by 10 publications

References 28 publications

One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones

One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

Recent Developments in the Synthesis of Imidazo[1,2-a]pyridines

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