The Vinylogous Michael Reaction – A Novel Perspective for Biaryl Synthesis

Christoffers, Jens; Mann, Alexander

doi:10.1002/(sici)1099-0690(199910)1999:10<2511::aid-ejoc2511>3.0.co;2-3

Cited by 13 publications

(3 citation statements)

References 12 publications

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“…A dioxane solution of 3 ([ 3 ] 0 = 25 mM), 4 (10 mol %), and n -tetradecane (internal standard) was stirred at room temperature for 16 h. GC analysis of the reaction mixture revealed formation of cyclohexanone 5 (80%), 2,4-octanedione ( 13 , 4%), 2-acyl-1-hydroxy-1,3-hexadiene [ 14 , 3% (∼7:1 mixture of dienolic and keto tautomers], and 2-acetylphenol ( 15 , 3%) (Scheme ). In a separate experiment, a dioxane solution of 3 ([ 3 ] 0 = 25 mM) and 4 (10 mol %) was stirred for 16 h at room temperature and concentrated under vacuum.…”

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confidence: 99%

“…(a) Because 14 tautomerizes under acidic conditions to form a ∼1:1 mixture of 2-carbomethoxy-2-cyclohexenone and 2-carbomethoxy-1-hydroxy-1,3-cyclohexadiene,52b the predominant formation of 2-acyl-1-hydroxy-1,3-hexadiene ( 7 - enol ) relative to 2-acyl-2-cyclohexenone ( 7 - keto ) strongly suggests that 7 - enol is formed as the kinetic product in these transformations.…”

Section: Referencesmentioning

confidence: 99%

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Development, Scope, and Mechanism of the Palladium-Catalyzed Intramolecular Hydroalkylation of 3-Butenyl β-Diketones

2004

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Reaction of 7-octene-2,4-dione (3) with a catalytic amount of PdCl2(CH3CN)2 (4) (10 mol %) in dioxane at room temperature for 16 h formed 2-acetylcyclohexanone (5) in 81% yield as a single regioisomer. Byproducts in the conversion of 3 to 5 include 2,4-octanedione (13), 2-acetyl-2-cyclohexenone (14), 2-acetylphenol (15), (E)- and (Z)-6-octene-2,4-dione (17), (E)- and (Z)-5-octene-2,4-dione (18), the η3-β-diketonate chloride dimer {[η3-CH3CH2CH2CHCOHCHAc]Pd(Cl)}2 (12), and the π(allyl)palladium chloride dimer {[η3-CH3CHCHCHC(O)CH2Ac]Pd(Cl)}2 (16). The palladium-catalyzed cyclization of 3-butenyl β-diketones tolerated substitution at the terminal acyl carbon atom, the enolic carbon atom, and the terminal olefinic carbon atom. Deuterium-labeling studies, in conjunction with kinetic and in situ NMR experiments, supported a mechanism for the palladium-catalyzed hydroalkylation of 3-butenyl β-diketones initiated by 6-endo-trig attack of the enol carbon atom on a palladium-complexed olefin to form a palladium cyclohexanone species. Migration of the palladium atom from the C(4) to the C(6) carbon atom of the 2-acylcyclohexanone intermediate via iterative β-hydride elimination/addition followed by protonolysis of the resulting palladium C(6)-enolate complex released the cyclohexanone and regenerated the palladium dichloride catalyst.

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Section: Resultsmentioning

confidence: 99%

Section: Referencesmentioning

confidence: 99%

Development, Scope, and Mechanism of the Palladium-Catalyzed Intramolecular Hydroalkylation of 3-Butenyl β-Diketones

2004

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“…[6] In all these cases, the addition has been applied in a racemic version, most likely as a result of the incompatibility of the different asymmetric catalytic metal systems with the redox quinine-hydroquinone system. [7] Thus, we decided to perform the addition of substituted bketoesters to 1,4-naphthoquinone under organocatalysis. We started out by studying the reaction under phase-transfer conditions using cinchona alkaloids.…”

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Organocatalytic Highly Enantioselective α‐Arylation of β‐Ketoesters.

2007

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Enantioselective syntheses O 0031Organocatalytic Highly Enantioselective α-Arylation of β-Ketoesters. -The first organocatalytic asymmetric addition of cyclic β-ketoesters towards quinone derivatives uses cinchona alkaloids as catalysts and provides access towards quinones like (III) or (V) or hydroquinones like (XIII) depending on the conditions. Best results are achieved with 5-membered cyclic β-ketoesters like (I) or (X) [except the reaction with o-quinone (IV)]. In the case of 6-membered cyclic β-ketoesters (XII) and (XIV), the more reactive dichloroquinone (VIII) is necessary for good results. The usefulness of the method is demonstrated in a one-pot synthesis of the structurally complex spirocyclic compound (IX). -(ALEMAN, J.; RICHTER, B.; JOERGENSEN*, K. A.; Angew. Chem., Int. Ed. 46 (2007) 29, 5515-5519; Dep. Chem., Univ. Aarhus, DK-8000 Aarhus, Den.; Eng.) -Mischke 47-022

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Synthesis of Biaryl Compounds by Vinylogous Michael Reactions

Christoffers¹,

Mann

2000

Eur. J. Org. Chem.

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Acceptor‐substituted cycloalkenones 1 undergo an iron(III)‐catalyzed vinylogous Michael reaction − a sequence of enone−dienol tautomerism, [4+2]‐cycloaddition, and retro‐aldol reaction − with quinone derivatives 3. A variety of products is obtained ranging from meta‐terphenyl precursors 5 to dihydronaphthobenzofurans 7. Reaction of 1,2‐naphthoquinone (3e) with vinylogous donors 1 yields cross‐coupled products 12, which can be further converted into highly functionalized biaryl compounds 13 and 14.

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The Vinylogous Michael Reaction – A Novel Perspective for Biaryl Synthesis

Cited by 13 publications

References 12 publications

Development, Scope, and Mechanism of the Palladium-Catalyzed Intramolecular Hydroalkylation of 3-Butenyl β-Diketones

Development, Scope, and Mechanism of the Palladium-Catalyzed Intramolecular Hydroalkylation of 3-Butenyl β-Diketones

Organocatalytic Highly Enantioselective α‐Arylation of β‐Ketoesters.

Synthesis of Biaryl Compounds by Vinylogous Michael Reactions

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