- Au-promoted Pd-catalyzed arylative cyclization of N,N-dimethyl-o-alkynylaniline with aryl iodides: Access to 2,3-diaryl indoles and mechanistic insight
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We have developed a Au-promoted Pd-catalyzed cyclization/cross-coupling of N,N-dimethyl-o-alkynylaniline with aryl iododes to synthesize 2,3-diarylindoles under mild and base-free conditions. A related vinyl-Au species has been isolated through Au-promoted cyclization of N,N-dimethyl-o-alkynylaniline and structurally characterized. Further study on its reactivity suggests the vinyl-Au species might be out of catalytic cycle, and PhPd(OTf)(PPh3)2 is probably the reaction intermediate.
- Yuan, Kemeng,Wang, Jiwei,Wang, Feijun,Zhang, Jun
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supporting information
(2021/02/01)
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- Intramolecular Addition of a Dimethylamino C(sp 3)-H Bond across C-C Triple Bonds Using IrCl(DTBM-SEGPHOS)(ethylene) Catalyst: Synthesis of Indoles from 2-Alkynyl- N -methylanilines
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Intramolecular addition of a C(sp 3)-H bond of the dimethylamino group across the C-C triple bond in 2-alkynyl- N, N -dimethylanilines is effectively catalyzed by a new iridium complex, IrCl(DTBM-SEGPHOS)(C 2H 4), in mesitylene at 150 °C. The intramolecular C(sp 3)-H addition is followed by double-bond isomerization to afford 3-substituted indoles in good to high yields.
- Ohmura, Toshimichi,Yagi, Kaito,Torigoe, Takeru,Suginome, Michinori
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supporting information
p. 3057 - 3064
(2021/06/28)
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- Metal-Free and syn-Selective Hydrohalogenation of Alkynes through a Pseudo-Intramolecular Process
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A new metal-free hydrohalogenation method for alkynes has been developed, which proceeds through a pseudo-intramolecular process. In this reaction, ethynylaniline serves as a substrate to quantitatively form an anilinium salt upon treatment with hydrochloric acid. The spatial proximity facilitates the efficient electrophilic addition of HCl to the ethynyl group in syn-mode, affording the corresponding chloroalkene without overaddition. This protocol was applied to HBr and HI, and the corresponding bromo- and iodoalkenes were obtained, respectively. The obtained chloroalkene was converted to tri-substituted alkenes possessing different aryl/alkynyl groups through Pd-catalyzed cross-coupling reactions.
- Asahara, Haruyasu,Mukaijo, Yusuke,Muragishi, Kengo,Iwai, Kento,Ito, Akitaka,Nishiwaki, Nagatoshi
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p. 5747 - 5755
(2021/10/20)
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- Copper-Catalyzed Three-Component Carboamination of Arynes: Expeditious Synthesis of o-Alkynyl Anilines and o-Benzoxazolyl Anilines
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A copper-catalyzed three-component reaction of in situ formed arynes, terminal alkynes, and O-benzoylhydroxylamines has been developed. By adjusting reaction conditions, the nucleophiles in this transformation can be extended from terminal alkynes to benzoxazoles. These procedures provide a modular and facile approach to o-alkynyl anilines and o-benzoxazolyl anilines from easily available substrates in only one step.
- Niu, Sheng-Li,Hu, Jiangtao,He, Kuicheng,Chen, Ying-Chun,Xiao, Qing
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supporting information
p. 4250 - 4254
(2019/06/07)
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- Palladium-Catalyzed Synthesis of 2,3-Diaryl- N-methylindoles from ortho-Alkynylanilines and Aryl Pinacol Boronic Esters
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A palladium-catalyzed synthesis of 2,3-diaryl-N-methylindoles from o-alkynylanilines and aryl pinacol boronic esters was developed. The system possesses high functional group tolerance and a broad substrate scope with a variety of aryl pinacol boronic est
- Luo, Yue-Gui,Basha, R. Sidick,Reddy, Daggula Mallikarjuna,Xue, Yong-Jing,Chen, Te-Hsuan,Lee, Chin-Fa
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supporting information
p. 6872 - 6876
(2018/11/21)
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- BCl3-Induced Annulative Oxo- and Thioboration for the Formation of C3-Borylated Benzofurans and Benzothiophenes
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BCl3-induced borylative cyclization of aryl-alkynes possessing ortho-EMe (E=S, O) groups represents a simple, metal-free method for the formation of C3-borylated benzothiophenes and benzofurans. The dichloro(heteroaryl)borane primary products can be protected to form synthetically ubiquitous pinacol boronate esters or used in situ in Suzuki–Miyaura cross couplings to generate 2,3-disubstituted heteroarenes from simple alkyne precursors in one pot. In a number of cases alkyne trans-haloboration occurs alongside, or instead of, borylative cyclization and the factors controlling the reaction outcome are determined.
- Warner, Andrew J.,Churn, Anna,McGough, John S.,Ingleson, Michael J.
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supporting information
p. 354 - 358
(2016/12/30)
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- Synthesis of: N -alkyl-3-sulfonylindoles and N -alkyl-3-sulfanylindoles by cascade annulation of 2-alkynyl- N, N -dialkylanilines
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An efficient and metal-free approach to N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles from 2-alkynyl-N,N-dialkylanilines has been developed. In the presence of iodine and tert-butylhydroperoxide (TBHP), a variety of 2-alkynyl-N,N-dialkylanilines underwent a cascade radical annulation to yield 3-arylsulfonylindoles. In contrast, 3-arylsulfanylindoles were conveniently prepared by iodine mediated electrophilic annulation reactions. The present protocol uses the economical and environmentally friendly I2-TBHP or I2 system, and potentially bioactive N-alkyl-3-sulfonylindoles and N-alkyl-3-sulfanylindoles with various functional groups were successfully synthesized in moderate to good yields.
- Meesin, Jatuporn,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Leowanawat, Pawaret,Kuhakarn, Chutima
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supporting information
p. 3662 - 3669
(2017/07/07)
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- Pd/phenanthroline-catalyzed arylative cyclization of o-(1-alkynyl)thioanisoles: Synthesis of 3-arylated benzo[b]thiophenes
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The arylative cyclization of o-(1-alkynyl)thioanisoles with aryl iodides in the presence of catalytic amounts of [Pd(phen)2][PF6]2resulted in the efficient formation of 3-arylated benzo[b]thiophenes, and a range of aryl iodides with electron-donating or -withdrawing groups could be used. While this reaction proceeded in the presence of aromatic and aliphatic groups on the terminal alkynyl carbon atom, silyl and alkoxycarbonyl groups hampered the reaction. Furthermore, this method could be extended to the synthesis of 3-arylated indoles from N,N-dimethyl-o-(1-alkynyl)aniline. All these reactions proceeded smoothly via cleavage of the carbon-heteroatom bond. In addition to the desired cyclization products, the use of a o-(hydroxypropyl)phenylmethyl substituent on the sulfur atom afforded isochroman, which should be formed by the intramolecular attack of a hydroxy group onto the benzylic carbon atom.
- Yamauchi, Takayuki,Shibahara, Fumitoshi,Murai, Toshiaki
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supporting information
p. 2945 - 2948
(2016/07/06)
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- Position of substitution: A facile way to tune the spectroscopic properties of dimethylamino-substituted arylene-ethynylenes
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A series of dimethylamino-substituted arylene-ethynylenes were synthesised by Sonogashira coupling reactions and characterised by the methods of 1H, 13C NMR, UV-Vis, fluorescence, HRMS and theoretical calculations. Effects on spectroscopic properties caus
- Fang, Jing-Kun,Sun, Tengxiao,Fang, Yu,Xu, Zhimin,Zou, Hui,Liu, Yuan,Ge, Fangting
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p. 487 - 491
(2015/11/03)
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- Pd/C-catalyzed cyclizative cross-coupling of two ortho-alkynylanilines under aerobic conditions: Synthesis of 2,3′-bisindoles
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Abstract A palladium-catalyzed cyclizative cross-coupling of two o-alkynylanilines to 2,3′-bisindoles under aerobic oxidative conditions was developed. Mechanistic studies suggested that the two catalytic cycles, namely the formation of 3-alkynylindoles 8
- Yao, Bo,Wang, Qian,Zhu, Jieping
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supporting information
p. 7413 - 7416
(2015/05/13)
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- A new synthesis of indoles via intramolecular cyclization of ?-alkynyl N,N-dialkylanilines promoted by KOt-Bu/DMSO
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2-Aryl indoles could be prepared in excellent yields via the intramolecular cyclization of ?-alkynyl N,N-dialkylanilines. The reaction is efficiently promoted by the catalytic amount of KOt-Bu in DMSO at room temperature. A reaction mechanism involving α-
- Chen, Yan-Yan,Chen, Jia-Hua,Zhang, Niu-Niu,Ye, Lin-Miao,Zhang, Xue-Jing,Yan, Ming
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supporting information
p. 478 - 481
(2015/03/05)
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- A new synthesis of indoles via intramolecular cyclization of ο-alkynyl N,N-dialkylanilines promoted by KOt-Bu/DMSO
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2-Aryl indoles could be prepared in excellent yields via the intramolecular cyclization of ο-alkynyl N,N-dialkylanilines. The reaction is efficiently promoted by the catalytic amount of KOt-Bu in DMSO at room temperature. A reaction mechanism involving α-
- Chen, Yan-Yan,Chen, Jia-Hua,Zhang, Niu-Niu,Ye, Lin-Miao,Zhang, Xue-Jing,Yan, Ming
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supporting information
p. 478 - 481
(2015/04/27)
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- CuBr-promoted tandem cyclization/trifluoromethylation of 2-alkynylanilines: Efficient synthesis of 3-trifluoromethylindoles
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A new efficient strategy for the synthesis of 3-trifluoromethyl-indoles was developed through tandem cyclization/ trifluoromethylation of 2-alkynylanilines and Umemoto’s reagent under effect of CuBr. The reaction features the use of cheap copper salt, mil
- Ge, Guangcun,Huang, Xiaojun,Ding, Changhua,Li, Hao,Wan, Shili,Hou, Xuelong
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supporting information
p. 727 - 733
(2014/10/16)
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- Palladium-catalyzed coupling of ortho-alkynylanilines with terminal alkynes under aerobic conditions: Efficient synthesis of 2,3-disubstituted 3-alkynylindoles
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Two nucleophiles, one triple bond: Under aerobic conditions, palladium-catalyzed direct coupling of o-alkynylanilines and terminal alkynes took place smoothly to afford the 2,3-disubstituted 3-alkynylindoles 3 in good to excellent yields. The intermediate A was characterized and a retro-aminopalladation of B was observed for the first time. Copyright
- Yao, Bo,Wang, Qian,Zhu, Jieping
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supporting information
p. 12311 - 12315
(2013/02/23)
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- Palladium(II)-catalyzed tandem cyclization/C-H functionalization of alkynes for the synthesis of functionalized indoles
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A palladium-catalyzed tandem cyclization/C-H functionalization of two alkynes was accomplished to construct a series of polycyclic functionalized indoles. A range of internal alkynes bearing synthetically useful functional groups were tolerated. A good regioselectivity was observed when alkyl-substituted alkynes were introduced into the reaction system, and a single product was obtained. Molecular oxygen was used as the terminal oxidant in the approach, rendering the reaction more sustainable.
- Xia, Xiao-Feng,Wang, Ning,Zhang, Lu-Lu,Song, Xian-Rong,Liu, Xue-Yuan,Liang, Yong-Min
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p. 9163 - 9170
(2013/01/15)
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- A novel synthetic route to 3-sulfenyland 3-selenylindoles by n-bu 4ni-induced electrophilic cyclization
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3-Sulfenyl-and 3-selenylindoles are prepared in excellent yields by the palladium/copper-catalyzed crossing coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclization with arylsulfenyl chlorides and arylselenyl chlorides in the presence of a stoichiometric amount of n-Bu4NI.
- Chen, Yu,Cho, Chul-Hee,Larock, Richard C.
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supporting information; experimental part
p. 173 - 176
(2009/06/20)
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- Synthesis of 3-sulfenyl- and 3-selenylindoles by the Pd/Cu-catalyzed coupling of N,N-dialkyl-2-iodoanilines and terminal alkynes, followed by n-Bu4NI-induced electrophilic cyclization
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(Chemical Equation Presented) 3-Sulfenyl- and 3-selenylindoles are readily synthesized by a two-step process involving the palladium/copper-catalyzed crossing coupling of N,N-dialkyl-ortho-iodoanilines and terminal alkynes and subsequent electrophilic cyclization of the resulting N,N-dialkyl-ortho-(1- alkynyl)anilines with arylsulfenyl chlorides or arylselenyl chlorides. The presence of a stoichiometric amount of n-Bu4NI is crucial to the success of the electrophilic cyclization. A variety of 3-sulfenyl- and 3-selenylindole derivatives bearing alkyl, vinylic, aryl, and heteroaryl substituents have been prepared in good to excellent yields (up to 99%). By employing N,N-dibenzyl-ortho-iodoanilines, a 3-sulfenyl-N-H-indole has been successfully prepared. In addition, 3-sulfonyl- and 3-sulfinylindoles have also been successfully prepared by facile oxidation of the corresponding 3-sulfenylindoles.
- Chen, Yu,Cho, Chul-Hee,Shi, Feng,Larock, Richard C.
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supporting information; experimental part
p. 6802 - 6811
(2009/12/30)
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- An efficient, microwave-assisted, one-pot synthesis of indoles under Sonogashira conditions
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A microwave-assisted, one-pot, three-component coupling reaction for the synthesis of indoles has been developed. The reaction is carried out in two steps under standard Sonogashira coupling conditions from an N-substituted/N,N-disubstituted 2-iodoaniline and a terminal alkyne, followed by the addition of acetonitrile and an aryl iodide. A variety of polysubstituted indoles have been prepared in moderate to excellent yields using the present method.
- Chen, Yu,Markina, Nataliya A.,Larock, Richard C.
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experimental part
p. 8908 - 8915
(2009/12/08)
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- Synthesis of 3-iodoindoles by the Pd/Cu-catalyzed coupling of N,N-dialkyl-2-iodoanilines and terminal acetylenes, followed by electrophilic cyclization
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3-Iodoindoles have been prepared in excellent yields by coupling terminal acetylenes with N,N-dialkyl-o-iodoanilines in the presence of a Pd/Cu catalyst, followed by an electrophilic cyclization of the resulting N,N-dialkyl-o-(1- alkynyl)anilines using I
- Yue, Dawei,Yao, Tuanli,Larock, Richard C.
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- Can polarization of triple bond in tolanes be deduced from 13C NMR shifts? Re-evaluation of factors affecting regiochemistry of the palladium-catalyzed hydrostannation of alkynes
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Polarization of the triple bond in a series of differently substituted ortho and para-tolanes has been studied by NMR and computational methods in order to examine if 13C NMR data can be effectively used for the assessment of electronic polarization of a triple bond in diarylacetylenes. DFT calculations of both natural charges and NMR properties revealed that chemical shifts concur with effective charges on sp-carbon atoms in para-tolanes, whereas in ortho-analogues magnetic anisotropy complicates the analysis making 13C NMR data inapplicable for ascribing triple bond polarization. The obtained information was used to reevaluate factors affecting the regiochemistry of the Pd-catalyzed hydrostannation of the triple bond in tolanes. Computational study on the polarization of triple bonds taken together with the experimental data on hydrostannation of various mono- and disubstituted tolanes bearing para- and ortho-substituents demonstrated that the regioselectivity of hydrostannation is governed by a combination of electronic and steric factors. In para-tolanes, the electronic effect prevails and α- and β-vinylstannanes are obtained predominantly for substrates with electron-withdrawing and electron-donating groups, respectively. In the ortho-series, steric factors dominate over electronics and α-isomers are produced with high selectivity regardless of the substituents' nature. However, it was found that in disubstituted "push-pull" tolanes steric control of an ortho-group can be overruled by the very strong electronic effect of an electron-withdrawing substituent in para-position.
- Rubin, Michael,Trofimov, Alexander,Gevorgyan, Vladimir
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p. 10243 - 10249
(2007/10/03)
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- Synthesis of 3-iodoindoles by electrophilic cyclization of N,N-dialkyl-2-(1-alkynyl)anilines
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(Equation presented) A wide variety of N-alkyl-3-iodoindoles are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclizatio
- Yue, Dawei,Larock, Richard C.
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p. 1037 - 1040
(2007/10/03)
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- Sonogashira Coupling Reaction with Palladium Powder, Potassium Fluoride in Aqueous Media
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A Sonogashira coupling reaction of aromatic iodides and bromides with terminal alkynes in the presence of palladium powder, potassium fluoride, cuprous iodide, and triphenylphosphine in aqueous media was developed. The reaction generates the corresponding
- Wang, Lei,Li, Pinhua
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p. 3679 - 3685
(2007/10/03)
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- Sonogashira coupling and cyclization reactions on alumina: A route to aryl alkynes, 2-substituted-benzo[b]furans and 2-substituted-indoles
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A solventless, microwave-enhanced Sonogashira coupling reaction of aromatic iodides with terminal alkynes on potassium fluoride doped alumina in the presence of palladium powder, cuprous iodide, and triphenylphosphine has been developed. The reaction can be utilized to prepare aryl alkynes in excellent yields. The coupling of o-iodophenol with terminal alkynes leads to the formation 2-substituted-benzo[b]furans. Whereas the coupling of o-iodoanilines with terminal alkynes generates indole products. An in situ desilylation reaction was also developed.
- Kabalka, George W.,Wang, Lei,Pagni, Richard M.
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p. 8017 - 8028
(2007/10/03)
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- Rapid microwave-enhanced, solventless Sonogashira coupling reaction on alumina
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A microwave-enhanced, solventless Sonogashira coupling reaction has been developed. Terminal alkynes couple with aryl or alkenyl iodide on palladium- doped alumina in the presence of triphenylphosphine and cuprous iodide to provide high yields of products. (C) 2000 Published by Elsevier Science Ltd.
- Kabalka, George W.,Wang, Lei,Namboodiri, Vasudevan,Pagni, Richard M.
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p. 5151 - 5154
(2007/10/03)
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