Synthesis of (E)-α-Ethynyl-α,β-unsaturated Esters from Allenyl Acetates Catalyzed by DABCO and Their Application to Sonogashira Cross-Coupling Reactions

Shin, Doosup; Lee, Kwangmoo; Lee, Sangkyu; Kim, Sanghyuk; Lee, Phil Ho

doi:10.5012/bkcs.2010.31.03.742

Cited by 11 publications

(1 citation statement)

References 35 publications

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“…According to the control experimental results and previous studies, a possible mechanism, involving a SPC process, was proposed to account for the formation of 3-ethynyl-substituted tetrahydroquinoline derivatives (Scheme ). Initially, the Lee–Tong intermediate II was produced by a phosphine catalyst from α-substituted allenoates 2 via an addition and elimination reaction. , Then the key intermediate 4a was obtained by the elimination of the phosphine catalyst from Int II under the base to accomplish the first catalytic cycle (Scheme ). Subsequently, in a recatalytic process, nucleophilic attack of PR 3 to 4a generated intermediate III .…”

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confidence: 99%

Sequential Phosphine-Catalyzed [4 + 2] Annulation of β′-Acetoxy Allenoates: Enantioselective Synthesis of 3-Ethynyl-Substituted Tetrahydroquinolines

et al. 2019

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The first enantioselective sequential phosphine-catalyzed (SPC as abbreviation) mode for the formation of tetrahydroquinolines with an ethynyl-substituted all-carbon quaternary stereogenic center is reported. In this SPC process, a novel [4 + 2] annulation process was devised employing α-substituted allenoates as C2 synthons (α–β′, 1,2-dipole) for the first time. 3-Ethynyl-substituted tetrahydroquinolines were readily prepared in good yields and high enantioselectivities.

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confidence: 99%

Sequential Phosphine-Catalyzed [4 + 2] Annulation of β′-Acetoxy Allenoates: Enantioselective Synthesis of 3-Ethynyl-Substituted Tetrahydroquinolines

et al. 2019

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Formation of Alkynes by Elimination Reactions

Larock

Zhang

2018

Comprehensive Organic Transformations

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Palladium‐Catalyzed Allyl Cross‐Coupling Reactions with In Situ Generated Organoindium Reagents

Lee

2011

Chemistry An Asian Journal

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Inter- and intramolecular palladium-catalyzed allyl cross-coupling reactions, using allylindium generated in situ from allyl halides and indium, is demonstrated. Allylindium compounds may be effective nucleophilic coupling partners in palladium-catalyzed cross-coupling reactions. A variety of allyl halides, such as allyl iodide, allyl bromide, crotyl bromide, prenyl bromide, geranyl bromide, and 3-bromocyclohexene afforded the allylic cross-coupling products in good to excellent yields. Stereochemistry of the double bond is retained in the allylic cross-coupling reactions. Electrophilic cross-coupling partners, such as aryl and vinyl halides, dibromoolefin, alkynyl iodide, and aryl and vinyl triflates participate in these reactions. The presence of various substituents, such as n-butyl, ketal, acetyl, ethoxycarbonyl, nitrile, N-phenylamido, nitro, and chloride groups on the aromatic ring of electrophilic coupling partners showed little effect on the efficiency of the reactions. The present conditions work equally well for not only intermolecular but also intramolecular palladium-catalyzed cross-coupling reactions. These methods provide an efficient synthetic method for the introduction of an allyl group, which can be easily further functionalized to afford an sp(2)- and sp-hybridized carbon. The present method complements existing synthetic methods as a result of advantageous features such as easy preparation and handling, thermal stability, high reactivity and selectivity, operational simplicity, and low toxicity of allylindium reagents.

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Synthesis of (E)-α-Ethynyl-α,β-unsaturated Esters from Allenyl Acetates Catalyzed by DABCO and Their Application to Sonogashira Cross-Coupling Reactions

Cited by 11 publications

References 35 publications

Sequential Phosphine-Catalyzed [4 + 2] Annulation of β′-Acetoxy Allenoates: Enantioselective Synthesis of 3-Ethynyl-Substituted Tetrahydroquinolines

Sequential Phosphine-Catalyzed [4 + 2] Annulation of β′-Acetoxy Allenoates: Enantioselective Synthesis of 3-Ethynyl-Substituted Tetrahydroquinolines

Formation of Alkynes by Elimination Reactions

Palladium‐Catalyzed Allyl Cross‐Coupling Reactions with In Situ Generated Organoindium Reagents

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