- Cobalt-Catalyzed Bis-alkynylation of Amides via Double C-H Bond Activation
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The first example of cobalt-catalyzed selective bis-alkynylation of amides via double C-H bond activation with the directing assistance of a removable bidentate auxiliary is reported. The developed alkynylation strategy is simple, efficient, and tolerant
- Landge, Vinod G.,Jaiswal, Garima,Balaraman, Ekambaram
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- Copper-Catalyzed Modular Access to N-Fused Polycyclic Indoles and 5-Aroyl-pyrrol-2-ones via Intramolecular N—H/C—H Annulation with Alkynes: Scope and Mechanism Probes
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Copper-catalyzed intramolecular N—H/C—H annulation with alkynes has been developed. A variety of densely functionalized heterocycles, such as pyrrolo[1,2-a]indoles, indolo[1,2-c]quinazolin-2-ones, oxazolo[3,4-a]indoles, and imidazo[1,5-a]indoles, were synthesized in an atom- and step-economical manner, owing to the high modularized feature of aniline moiety, the linker moiety, as well as the alkyne moiety. By simply changing the oxidant from di-tert-butyl peroxide (DTBP) to 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), the reaction could readily be transformed to the aminooxygenation pathway, which grabs one oxygen atom from the TEMPO to generate 5-aroyl-pyrrol-2-ones. Mechanistic experiments indicate that vinyl radical is involved in this reaction and an amidyl-radical-initiated radical cascade might be responsible for this transformation.
- Liu, Yan-Hua,Song, Hong,Zhang, Chi,Liu, Yue-Jin,Shi, Bing-Feng
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supporting information
p. 1545 - 1552
(2020/09/09)
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- Sterically Controlled Late-Stage C-H Alkynylation of Arenes
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Phenylacetylenes are key structural motifs in organic chemistry, which find widespread applications in bioactive molecules, synthetic intermediates, functional materials, and reagents. These molecules are typically prepared from prefunctionalized starting materials, e.g. using the Sonogashira coupling, or using directing group-based C-H activation strategies. While highly efficient, these approaches remain limited by their inherent selectivities for specific regioisomers. Herein we present a complementary approach based on an arene-limited nondirected C-H activation. The reaction is predominantly controlled by steric rather than electronic factors and thereby gives access to a complementary product spectrum with respect to traditional methods. A broad scope as well as the suitability of this protocol for late-stage functionalization are demonstrated.
- Mondal, Arup,Chen, Hao,Fl?mig, Lea,Wedi, Philipp,Van Gemmeren, Manuel
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supporting information
p. 18662 - 18667
(2019/11/28)
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- Nickel-catalyzed direct alkynylation of C(sp2)-H bonds of amides: An "inverse Sonogashira strategy" to ortho-alkynylbenzoic acids
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Nickel-catalyzed direct alkynylation of C(sp2)-H bonds of amides using commercially available, inexpensive 8-aminoquinoline as a removable bidentate directing group is described. The present ortho-alkynylation has a broad substrate scope, funct
- Landge, Vinod G.,Shewale, Chinmay H.,Jaiswal, Garima,Sahoo, Manoj K.,Midya, Siba P.,Balaraman, Ekambaram
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p. 1946 - 1951
(2016/04/05)
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- Synthesis of isocoumarins and α-pyrones via electrophilic cyclization
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A variety of substituted isocoumarins and α-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(1-alkynyl)benzoates and (Z)-2-alken-4-ynoates with ICl, I2, PhSeCl, p-O2NC6/
- Yao, Tuanli,Larock, Richard C.
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p. 5936 - 5942
(2007/10/03)
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- Coupling reactions of ortho-substituted halobenzenes with alkynes. The synthesis of phenylacetylenes and symmetrical or unsymmetrical 1,2-diphenylacetylenes
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The Pd- or Pd/Cu-catalyzed coupling reactions of halobenzenes bearing the methyl, hydroxymethyl, acetoxymethyl, methoxycarbonyl, or both methoxy and 4,4-dimethyl-4,5-dihydro-1,3-oxazol-2-yl groups in the ortho-position with gaseous or metallated acetylene, (trialkylsilyl)acetylenes, and arylacetylenes have been systematically studied. Various functionalized aryl- or diarylacetylenes have been synthesized in good to excellent yields. Whereas additional fluoro, nitro, or methoxy group attached to the benzene ring does not interfere in the coupling reactions, the presence of a methoxycarbonyl requires a careful optimization of reaction conditions to achieve moderate yields.
- Stara, Irena G.,Stary, Ivo,Kollarovic, Adrian,Teply, Filip,Saman, David,Fiedler, Pavel
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p. 649 - 672
(2007/10/03)
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