Thia‐Michael Addition: An Emerging Strategy in Organic Synthesis

Wadhwa, Preeti; Kharbanda, Anupreet; Sharma, Anuj

doi:10.1002/ajoc.201700609

Cited by 84 publications

(63 citation statements)

References 112 publications

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“…Furthermore, thia-Michael additions of alkyl thiols to electron-poor olefins have been widely studied and applied in organic synthesis. [26] On the other hand, the seleno-Michael reaction of functionalised alkyl selenols has never been described, despite it would represent a powerful tool for the formation of new CÀ Se bonds.…”

Section: Introductionmentioning

confidence: 99%

Seleno‐Michael Reaction of Stable Functionalised Alkyl Selenols: A Versatile Tool for the Synthesis of Acyclic and Cyclic Unsymmetrical Alkyl and Vinyl Selenides

et al. 2019

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Seleno-Michael additions of stable functionalised primary alkyl selenols to activated alkenes and alkynes are described. In the presence of Al 2 O 3 , β-hydroxy-, β-amino-, and β-mercapto selenols react smoothly with electron-poor alkenes and alkynes to afford the corresponding unsymmetrical functionalised dialkyl-and alkylÀ vinyl-selenides in good yield. The very mild conditions allow a broad range of selenols and Michael acceptors to be converted into the corresponding synthetically valuable seleno-Michael adducts, demonstrating high selectivity and excellent functional group tolerance. Hydroxy-and mercapto-substituted vinyl selenides were efficiently employed for the synthesis of functionalised 1,3-oxaselenolanes, 1,3-thiaselenolanes, and 1,4thiaselenanes through intramolecular oxa-and thia-Michael additions. Furthermore, a NaH-promoted lactonization enables the synthesis of variously substituted 2-oxo-1,4-oxaselenanes from hydroxyÀ vinylselenides. Evaluation of thiol peroxidase-like properties of novel functionalised organoselenides demonstrated that they possess a remarkable catalytic antioxidant activity.

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Section: Introductionmentioning

confidence: 99%

Seleno‐Michael Reaction of Stable Functionalised Alkyl Selenols: A Versatile Tool for the Synthesis of Acyclic and Cyclic Unsymmetrical Alkyl and Vinyl Selenides

et al. 2019

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“…[3] Themild conditions of conjugate addition, as the Michael reaction has come to be colloquially known, also lend this reaction well to other areas of research such as bioconjugation or dynamic combinatorial chemistry. [4] As aresult, methods to synthesize a,b-unsaturated systems are highly prized. Convenient and efficient pathways include carbonyl olefination [5] and olefin cross-metathesis, [6] although the ability to directly generate a,b-unsaturated carbonyl compounds from their corresponding saturated counterparts by dehydrogenation adds considerable flexibility to synthetic planning.…”

mentioning

confidence: 99%

Chemoselective α,β‐Dehydrogenation of Saturated Amides

et al. 2018

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We report a method for the selective α,β‐dehydrogenation of amides in the presence of other carbonyl moieties under mild conditions. Our strategy relies on electrophilic activation coupled to in situ selective selenium‐mediated dehydrogenation. The α,β‐unsaturated products were obtained in moderate to excellent yields, and their synthetic versatility was demonstrated by a range of transformations. Mechanistic experiments suggest formation of an electrophilic SeIV species.

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“…On the basis of above control experiments (Scheme 3), we further initiated our effort to establish the importance of synergistic interaction between Larginine and ionic liquid by using NMR ( 1 H and 13 13 C NMR spectra of a mixture of L-arginine-[bmim]Br was also recorded and it was observed that the carboxylic group of L-arginine in the presence of [bmim]Br showed an upfield shift from 183.090 ppm to 181.066 ppm when compared with 13 C NMR spectra of individual L-arginine. It is worth pointing out that our observations based upon NMR spectra analysis were concordant with the observation of Ren et al [31] where they proposed that the head group of the amino acid along with the guanidine moiety of L-arginine interacts with the ionic liquid.…”

Section: Resultsmentioning

confidence: 99%

“…Despite the fact that there are some useful protocols for the synthesis of b-aryl-b-sulfanyl esters, the requirements of pre-synthesized b-aryl-a,b-unsaturated esters, metal catalyst, strongly basic conditions, longer reaction time and limited substrate scopes (Scheme 1) are some of the major drawbacks of reported methods. [12][13][14] To date, to the best of our knowledge a fully-fledged thia-Michael addition reaction on in situ generated b-aryl-a,b-unsaturated esters…”

Section: Introductionmentioning

confidence: 99%

Synergistic Cooperative Effect of L‐Arginine‐[bmim]Br in Cascade Decarboxylative Knoevenagel‐Thia‐Michael Addition Reactions: Green Approach Towards C−S Bond Formation with In Situ Generated Unactivated α,β‐Unsaturated Ester

et al. 2018

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In this report, a synergistic combination of L-arginine and [bmim]Br has been realized for the first time towards step-economical synthesis of b-aryl-b-sulfanyl esters from aromatic aldehyde, malonate and thiol via cascade thia-Michael addition reaction on in situ formed unactivated b-aryl-a,b-unsaturated esters (via decarboxylative Knoevenagel reaction) under metal-and acid/base-free conditions. Furthermore, the gram scalability and recyclability of the catalytic system (up to 5 cycles) makes our one-pot two-step protocol more economically efficient and synthetically attractive for cascade CÀC and CÀS bond formation than traditional two-step methods. The synergistic interaction of the catalytic system i. e. L-arginine with [bmim]Br has been probed by NMR ( 1 H and 13 C) studies. employing multicomponent cascade reaction strategy under the influence of green cooperative catalysis is not reported in the literature.Recently, a drift has been observed from the traditional mono-catalysis towards contemporary multi-catalysis particularly cooperative catalysis [15][16][17][18][19][20] which has allowed chemists to venture into the untouched horizon of organic synthesis by improving the reactivity and selectivity of the reactions. Inspired by the robustness of the synergistic [15][16][17] cooperative effect, we envisaged its potential for effective cascade decarboxylative Knoevenagel condensation [21][22][23] and nucleophilic thia-Michael addition reaction to afford the corresponding b-aryl-b-sulfanyl esters via in-situ generated unactivated b-aryl-a,b-unsaturated ester.In this report, a synergistic combination of Larginine and [bmim]Br promoted cascade decarboxylative Knoevenagel-thia-Michael addition reaction under metal-and acid/base-free conditions is described employing aldehyde, monoethyl malonate and thiol as commercially available starting materials towards synthesis of b-aryl-b-sulfanyl ester via CÀC and CÀS bond formation in one pot (Scheme 1).

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Thia‐Michael Addition: An Emerging Strategy in Organic Synthesis

Cited by 84 publications

References 112 publications

Seleno‐Michael Reaction of Stable Functionalised Alkyl Selenols: A Versatile Tool for the Synthesis of Acyclic and Cyclic Unsymmetrical Alkyl and Vinyl Selenides

Seleno‐Michael Reaction of Stable Functionalised Alkyl Selenols: A Versatile Tool for the Synthesis of Acyclic and Cyclic Unsymmetrical Alkyl and Vinyl Selenides

Chemoselective α,β‐Dehydrogenation of Saturated Amides

Synergistic Cooperative Effect of L‐Arginine‐[bmim]Br in Cascade Decarboxylative Knoevenagel‐Thia‐Michael Addition Reactions: Green Approach Towards C−S Bond Formation with In Situ Generated Unactivated α,β‐Unsaturated Ester

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