Recent application of oxa-Michael reaction in complex natural product synthesis

Hu, Jialei; Bian, Ming; Ding, Hanfeng

doi:10.1016/j.tetlet.2016.11.007

Cited by 75 publications

(29 citation statements)

References 177 publications

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“…[2] Given the versatility of the carbonyl functional group,t he Michael addition of an enolate to an unsaturated carbonyl group is one of the definitive methods for generating a1 ,5-dicarbonyl relationship,and as aconsequence,such transformations can be frequently found in total syntheses. [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.…”

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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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confidence: 99%

Chemoselective α,β‐Dehydrogenation of Saturated Amides

et al. 2018

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“…The intramolecular oxa‐Michael reaction (IMOMR) is a direct and rapid approach for carbon‐oxygen bond formation, which allows the construction of synthetically useful cyclic oxygen‐containing heterocycles . In particular, the IMOMR is exploited as a key step in cascade strategies for the preparation of chiral tetrahydropyrans (THPs) and tetrahydrofurans (THFs), which are prevalent in natural products (Figure ) . The syntheses of these motifs often commence from the chiral pool, to provide the desired enantiomer of the nucleophilic alcohol, prior to the IMOMR.…”

Section: Figurementioning

confidence: 99%

Alcohol Dehydrogenase‐Triggered Oxa‐Michael Reaction for the Asymmetric Synthesis of Disubstituted Tetrahydropyrans and Tetrahydrofurans

et al. 2019

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An alcohol dehydrogenase‐mediated asymmetric reduction and subsequent intramolecular oxa‐Michael reaction has been developed for the preparation of tetrahydropyrans (or oxanes) and tetrahydrofurans, in excellent conversion, yield and high enantiomeric and diastereomeric excess. To highlight the utility of the methodology, we report the synthesis of an analogue of the fungal antioxidant brocaketone A. Also described is the preparation of the (–)‐(R,R)‐enantiomer of the natural product, (+)‐(S,S)‐(cis‐6‐methyltetrahydropyran‐2‐yl)acetic acid.

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“…[1,2] Arthur Michael discovered this reaction in 1887. Owing to the complete atom economy,t he addition of H-Nu (Nu = CR 3 ,O H, NR 2 ,S R, etc.) to carbon-carbonm ultiple bonds is one of the most desired and extensively studied synthetic transformations in organic synthesis.…”

Section: Introductionmentioning

confidence: 99%

“…Oxa-, [3][4][5] aza-, [6][7][8] thia-, [9][10][11] and phospha- [12] Michael addition reactions are the conceptual extension to heteroatom-centered anions. Utility of the Michael additions for the constructiono f CÀCb ond employing carbon nucleophiles are very well developed.…”

Section: Introductionmentioning

confidence: 99%

KOtBu‐Catalyzed Michael Addition Reactions Under Mild and Solvent‐Free Conditions

Thiyagarajan

Krishnakumar

Gunanathan

2020

Chemistry An Asian Journal

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Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base‐catalyzed Michael addition reactions have been reported. However, known base‐catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side‐reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu‐catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa‐, aza‐, and thia‐) heteroatom nucleophiles. This catalytic process proceeds under solvent‐free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.

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Recent application of oxa-Michael reaction in complex natural product synthesis

Cited by 75 publications

References 177 publications

Chemoselective α,β‐Dehydrogenation of Saturated Amides

Chemoselective α,β‐Dehydrogenation of Saturated Amides

Alcohol Dehydrogenase‐Triggered Oxa‐Michael Reaction for the Asymmetric Synthesis of Disubstituted Tetrahydropyrans and Tetrahydrofurans

KOtBu‐Catalyzed Michael Addition Reactions Under Mild and Solvent‐Free Conditions

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