- Gold(I)-Catalyzed Oxidative 1,4-Additions of 3-En-1-ynamide with Nitrones via Carbon- versus Nitrogen-Addition Chemoselectivity
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This work reports gold-catalyzed 1,4-oxofunctionalizations of 3-en-1-ynamides with nitrones, yielding two distinct E-configured products. We obtained 1,4-oxoarylation products from 3-en-1-ynamides bearing C(4)-electron-donating substituents and 1,4-oxoamination products from those analogues bearing C(4)-aryl substituents. We propose that if vinylgold carbenes are stable, imines undergo a para-arylation on these gold carbenes. If vinylgold carbenes are highly electron-deficient, this N-attack is irreversible to enable 1,4-oxoaminations.
- Tanpure, Sudhakar Dattatray,Kale, Balaji S.,Liu, Rai-Shung
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p. 1394 - 1399
(2021/02/20)
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- Regio- and Stereoselective N-addition to an Open Bromo Vinyl Cation
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A protocol for the synthesis of thus far inaccessible bromo vinyl triflimides is presented. Our previously reported concept of assisted vinyl cation formation was engaged to achieve both a protonation of relatively electron poor bromo alkynes and a reaction with high regio- and stereoselectivity. To the best of our knowledge, this is the first stereoselective addition of an N-nucleophile to an open β-halovinyl cation.
- Chuchmareva, Marina,Collong, Arndt,Niggemann, Meike,Schr?der, Sebastian,Strauch, Christina
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supporting information
(2021/06/07)
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- Dual Gold-Catalyzed Formal Tetradehydro-Diels–Alder Reactions for the Synthesis of Carbazoles and Indolines
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This work reports a dual gold-catalyzed tetradehydro-Diels–Alder reaction for the synthesis of nitrogen-containing aromatic heterocycles. Under the catalytic system (IPrAuNTf2/DIPEA), indolines and carbazoles as well as other N-containing aromatic heterocycles were prepared in high yields with good functional group tolerance. Unlike the traditional thermal tetradehydro-Diels–Alder reactions, diluted reaction concentration and radical prohibitors are not required for this protocol. Experimental data support a mechanism involving gold vinylidene species, which undergoes a 6 π electrocyclization, followed with 1,2-hydrogen shift.
- Wang, Hong-Fa,Wang, Shi-Yue,Qin, Tian-Zhu,Zi, Weiwei
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p. 17911 - 17914
(2018/11/23)
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- Borane-catalyzed selective hydrosilylation of internal ynamides leading to β-silyl (Z)-enamides
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We have developed a borane-catalyzed regioand stereoselective hydrosilylation of internal ynamides for the first time. The scope of ynamide substrates and silane reactants was broad under mild reaction conditions, affording synthetically versatile β-silyl (Z)-enamide products. The observed stereoselectivity was reasoned to be due to the β-silicon effect on a postulated ketene iminium intermediate.
- Kim, Youngchan,Dateer, Ramesh B.,Chang, Sukbok
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supporting information
p. 190 - 193
(2017/11/27)
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- Gold-Catalyzed Intermolecular Ynamide Amination-Initiated Aza-Nazarov Cyclization: Access to Functionalized 2-Aminopyrroles
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A novel gold-catalyzed intermolecular ynamide amination-initiated aza-Nazarov cyclization has been developed, allowing the facile and efficient synthesis of various 2-aminopyrroles in moderate to good yields. Furthermore, a mechanistic rationale for this
- Shu, Chao,Wang, Yong-Heng,Shen, Cang-Hai,Ruan, Peng-Peng,Lu, Xin,Ye, Long-Wu
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supporting information
p. 3254 - 3257
(2016/07/13)
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- Zinc-Catalyzed Stereo- and Regioselective 1,4-Hydrative Fluorination of 3-En-1-ynamides with Selectfluor
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Zinc-catalyzed 1,4-oxofluorinations of 3-en-1-ynamides with Selectfluor in acetonitrile/water proceeded with high regio- and stereoselectivity, giving E-configured γ-fluoro-α,β-unsaturated amides efficiently. Our control experiments indicate that kinetica
- Jadhav, Appaso Mahadev,Huple, Deepak B.,Singh, Rahulkumar Rajmani,Liu, Rai Shung
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supporting information
p. 1017 - 1022
(2016/04/19)
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- Palladium-Catalyzed Regioselective Alkynylation of Pyrroles and Azoles under Mild Conditions: Application to the Synthesis of a Dopamine D-4 Receptor Agonist
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A mild and general method for the direct alkynylation of azoles such as pyrrole, indole, and 7-azaindole is described here. Using a simple catalytic system such as Pd(OAc)2 (2.5 mol %), P(tBu)2Me·HBF4 (5 mol %), and NaOAc (2 equiv) allowed the regioselective introduction of various alkynyl residues at the C-2 position of pyrroles. Interestingly, C-2 alkynylation was also observed on C-3-substituted indoles, whereas classical C-3 alkynylation was obtained on selected unsubstituted indoles and 7-azaindole. Our methodology has been illustrated by the efficient synthesis of a potential schizophrenia drug (dopamine D-4 inhibitor).
- Brachet, Etienne,Belmont, Philippe
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p. 7519 - 7529
(2015/08/18)
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- ZnII- and AuI-catalyzed regioselective hydrative oxidations of 3-En-1-ynes with selectfluor: Realization of 1,4-dioxo and 1,4-oxohydroxy functionalizations
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Catalytic 1,4-dioxo functionalizations of 3-en-1-ynes to (Z)- and (E)-2-en-1,4-dicarbonyl compounds are described. This regioselective difunctionalization was achieved in one-pot operation through initial alkyne hydration followed by in situ Selectfluor oxidation. The presence of pyridine alters the reaction chemoselectivity to give 4-hydroxy-2-en-1-carbonyl products instead. A cooperative action of pyridine and ZnII assists the hydrolysis of key oxonium intermediate.
- Jadhav, Appaso Mahadev,Gawade, Sagar Ashok,Vasu, Dhananjayan,Dateer, Ramesh B.,Liu, Rai-Shung
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p. 1813 - 1817
(2014/03/21)
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- Facile and efficient synthesis of 1-haloalkynes via DBU-mediated reaction of terminal alkynes and N-haloimides under mild conditions
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Directly from terminal alkynes and with N-halosuccinimides (halo = Br and I) or N-cholorophthalimide as the halogen sources, DBU as the activator, 1-haloalkynes were prepared in good to excellent yields at room temperature. Bis(bromoalkyne) and bis(iodoal
- Li, Mengru,Li, Yueju,Zhao, Baozhong,Liang, Fushun,Jin, Long-Yi
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p. 30046 - 30049
(2014/08/05)
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- Copper-catalyzed cross-coupling of vinylsiloxanes with bromoalkynes: Synthesis of enynes
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Enynes are versatile building blocks in organic synthesis. A copper-catalyzed Hiyama-type cross-coupling of vinylsiloxanes with bromoalkynes is presented. This mild and efficient method led to the formation of various sensitive enynes. The use of cis, trans, and 1,1′-disubstituted vinylsiloxanes was allowed, and full retention of stereochemistry was observed. Sensitive groups such as halides, unsaturated ketones, and aldehydes were fully tolerated.
- Cornelissen, Loic,Lefrancq, Maxime,Riant, Olivier
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supporting information
p. 3024 - 3027
(2014/06/23)
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- Palladium-catalyzed alkynylative lactonization of unsaturated bicyclic carboxylic acids: Synthesis of fused polycyclic γ-lactone compounds
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Unsaturated bicyclic carboxylic acids undergo palladium-catalyzed coupling with bromoalkynes to produce γ-alkynyl lactones in moderate to good yields with excellent chemo- and regioselectivity. The reaction conditions were extremely mild, and functional groups such as methyl, methoxy, chloro, and bromo were tolerated under the optimized reaction conditions. Moreover, γ-chloroalkenyl lactones were facilely synthesized through chloropalladation/carboesterification of electron-deficient C≡C bonds by using molecular oxygen as the sole oxidant. Facile and tandem Pd-catalyzed synthesis of γ-alkynyl lactone and γ-chloroalkenyl lactone derivatives by using readily accessible bromoalkynes and unsaturated bicyclic carboxylic acids is reported. Two subsequent steps, namely, C(sp or sp 2)-C(sp3) bond formation and C-O bond formation, are catalyzed by a single Pd catalyst. The reactions proceed with good yields of the products. Copyright
- Sun, Ning,Li, Yibiao,Yin, Gengming,Jiang, Shaohua
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supporting information
p. 2541 - 2544
(2013/06/04)
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- Gold-catalyzed hydration of haloalkynes to α-halomethyl ketones
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A general atom-economical approach for the synthesis of α-halomethyl ketones is demonstrated through hydration of a wide range of haloalkynes. Other outstanding features include excellent yields from both alkyl- and aryl-substituted haloalkynes and wide functional group tolerance. This protocol is an alternative to conventional α-halogenation of ketones.
- Xie, Longyong,Wu, Yundong,Yi, Weiguo,Zhu, Lei,Xiang, Jiannan,He, Weimin
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p. 9190 - 9195
(2013/10/08)
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- Pd-catalyzed and CsF-promoted reaction of bromoalkynes with isocyanides: Regioselective synthesis of substituted 5-iminopyrrolones
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The palladium-catalyzed and CsF-promoted annulation reaction of bromoalkynes and isocyanides regioselectively affords a diverse set of 5-iminopyrrolone derivatives. This chemistry presumably proceeds through the bromoacrylamide intermediates, which can be readily prepared from the nucleophilic addition reaction of isocyanides to bromoalkynes in the presence of CsF.
- Li, Yibiao,Zhao, Jian,Chen, Huoji,Liu, Bifu,Jiang, Huanfeng
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supporting information; experimental part
p. 3545 - 3547
(2012/06/01)
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- Room temperature direct alkynylation of 1,3,4oxadiazoles with alkynyl bromides under copper catalysis
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("Figure Presented") The direct alkynylation reaction of 1,3,4-oxadiazoles with alkynyl bromides efficiently proceeds in the presence of a copper catalyst at room temperature to create the corresponding heteroaryl-alkynyl linkage in good yields. This direct coupling provides a rapid and convergent access to oxadiazole core Π-conjugated systems.
- Kawano, Tsuyoshi,Matsuyama, Naoto,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 1764 - 1766
(2010/05/01)
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- Bulky trialkylsilyl acetylenes in the Cadiot-Chodkiewicz cross-coupling reaction
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Bulky trialkylsilyl-protected alkynes such as triethylsilyl (TES), tert-butyldimethylsilyl (TBS), and tri-isopropylsilyl (TIPS) acetylenes underwent the Cadiot-Chodkiewicz cross-coupling reaction with different bromoalkynes to form a variety of synthetically useful unsymmetrical diynes in good yields. The diyne alcohol 10 was transformed regio- and stereoselectively into enynes by hydrotelluration, carbometalation, and reduction reactions.
- Marino, Joseph P.,Nguyen, Hanh Nho
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p. 6841 - 6844
(2007/10/03)
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- Synthesis of stereodefined β,γ-unsaturated ketones via hydroboration of 1-bromo-3-en-1-ynes
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Sequential hydroboration-oxidation of (E)- and (Z)-1-bromoenynes provides convenient access to (E)- and (Z)-β,γ-unsaturated ketones, respectively.
- Shoup,Zweifel
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p. 2937 - 2944
(2007/10/02)
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