- Expedient Iodocyclization Approach Toward Polysubstituted 3H-Benzo[e]indoles
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A facile and expedient iodocyclization of 4-(2-prop-1-ynylphenyl)-1H-pyrroles towards the synthesis of polysubstituted 3H-benzo[e]indoles is reported. The transformation was optimized and the best results were obtained by using iodine (1.2 equiv,) in dichloromethane, and potassium carbonate as base. The starting 1,2,3,4-tetrasubstituted pyrroles were efficiently obtained by means of a nickel(II) chloride-promoted four-component (nitromethane, amine, 2-alkynylbenzaldehyde and ethyl acetoacetate) reaction. Further functionalization of the resulting 5-iodoheterocycles was also explored.
- Martins, Guilherme M.,Zeni, Gilson,Back, Davi F.,Kaufman, Teodoro S.,Silveira, Claudio C.
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- Coupling of β-cyanocarbene-chromium complexes with 2-alkynylbenzoyl derivatives: A [5+5]-cycloaddition approach to phenanthridines
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The coupling of β-cyanocarbene complexes and 2-alkynylbenzoyl derivatives has been examined. The reaction afforded phenanthridine derivatives in a complex tandem process involving carbene-alkyne coupling, isobenzofuran formation, intramolecular Diels-Alder reaction using a nitrile dienophile, and deoxygenation. The chemistry could not be reproduced in non-chromium-based systems. Georg Thieme Verlag Stuttgart.
- Ghorai, Binay K.,Duan, Shaofeng,Jiang, Delu,Herndon, James W.
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- Exploiting Hydrazones to Improve the Efficiency of 6π-Electrocyclization Reactions of 1-Azatrienes
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The greater geometric lability of hydrazones compared to that of oxime ethers is used as a basis to overcome the reluctance of Z-oxime ether azatrienes to undergo electrocyclization toward the synthesis of borylated (heteroaromatic) pyridines and ring-fused analogues. Such hydrazones now allow access to previously inaccessible tri- and tetrasubstituted 3-borylpyridines in high yields.
- Ball-Jones, Matthew P.,Tyler, Jasper,Mora-Radó, Helena,Czechtizky, Werngard,Méndez, María,Harrity, Joseph P. A.
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- Metal/Benzoyl Peroxide (BPO)-Controlled Chemoselective Cycloisomerization of (o-Alkynyl)phenyl Enaminones: Synthesis of α-Naphthylamines and Indeno[1,2-c]pyrrolones
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Synthetic methods involving chemoselective tandem reactions for the synthesis of α-naphthylamines and indeno[1,2-c]pyrrolones starting from (o-aklynyl)phenyl enaminones are described. When reactions were carried out in N,N-dimethylformamide (DMF) using a AgNO3 catalyst, α-naphthylamines were obtained in up to 89% isolated yields within 2 h. Whereas indeno[1,2-c]pyrrolones were produced in high isolated yields in the presence of benzoyl peroxide (BPO) and CuCl catalysis.
- Zhang, Fangfang,Qin, Zhengchen,Kong, Lingkai,Zhao, Yulei,Liu, Yuanyuan,Li, Yanzhong
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- Enantioselective Construction of Vicinal Diaxial Styrenes and Multiaxis System via Organocatalysis
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A highly diastereo- and enantioselective methodology for the asymmetric synthesis of vicinal diaxial styrenes and multiaxis system was achieved by organocatalysis. Various vicinal diaxial styrenes and multiaxis systems were obtained in excellent enantioselective manners. The mechanism studies revealed that a new tetra-substituted vinylidene ortho-quinone methide (VQM) intermediate was likely involved and accounted for the excellent enantioselectivity.
- Tan, Yu,Jia, Shiqi,Hu, Fangli,Liu, Yidong,Peng, Lei,Li, Dongmei,Yan, Hailong
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- The cyclization reaction of ortho-ethynylbenzaldehyde derivatives into isoquinoline derivatives
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In order to elucidate the reaction mechanism of the cyclization between an ethynyl group and an imino group at the ortho-position on an aromatic ring to afford isoquinolines, reaction of 2-ethynylbenzaldehydes under various conditions was examined. It is concluded that reaction proceeds via an ionic process and the isoquinoline 4-hydrogen atom derives from the solvent. In addition, it was found that 2-ethynylbenzaldehyde O-methyloximes underwent cyclization in the presence of primary and secondary alcohols to give 3- substituted isoquinolines.
- Sakamoto, Takao,Numata, Atsushi,Kondo, Yoshinori
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- Rhodium-catalyzed regio- and enantioselective intermolecular [4+2] carbocyclization of 4-alkynals with N,N-dialkyl acrylamides
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(Chemical Equation Presented) Selective rings: A cationic Rh I-(R,R)-walphos complex catalyzes a highly regio-and enantioselective intermolecular [4+2] carbocyclization of 4-alkynals with N,N-dialkyl acrylamides to afford enantioenriched cyclohexanones (see scheme; cod = cycloocta-1,5-diene). This new route is attractive in view of the one-step access to 4-alkynals from commercially available reagents.
- Tanaka, Ken,Hagiwara, Yuji,Noguchi, Keiichi
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- Palladium-catalyzed esterification-hydroarylation reactions of 2-alkynyl-benzaldehydes with aryl iodides in methanol
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The reaction of 2-alkynylbenzaldehydes with aryl iodides in the presence of Pd(PPh3)4 and K2CO3 in refluxing methanol for 24 hours gave the dehydrogenation-addition products, methyl 2-(2,2-disubstituted-vinyl)benzoates in modest yields; together with the cyclization products, 3-methoxy-1-monosubstituted-methylene-3- hydroisobenzofurans in 3-18% yields.
- Wei, Li-Lan,Wei, Li-Mei,Pan, Wen-Bin,Wu, Ming-Jung
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- A versatile aminobenzannulation method based on the deprotonation of 2-(1-alkynyl)-benzaldimines and similar 2-aza-2,4-heptadienyl-6-ynes: A multistep rearrangement cascade
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Two ring closures, a ring opening, and two intermolecular proton shifts are the crucial steps in a cascade reaction that is triggered by the simple deprotonation of alkynylimines and leads ultimately to aminobenzannulation products (see scheme). The reactions proceed in good to very good yield and with excellent chemoselectivity.
- Sagar, Pramod,Froehlich, Roland,Wuerthwein, Ernst-Ulrich
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- Development of the Suzuki-Miyaura cross-coupling reaction: Use of air-stable potassium alkynyltrifluoroborates in aryl alkynylations
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The palladium-catalyzed cross-coupling reaction of potassium alkynyltrifluoroborates with aryl halides or triflates proceeds readily with moderate to excellent yields. The potassium alkynyltrifluoroborates are air- and moisture-stable crystalline solids t
- Molander, Gary A.,Katona, Bryson W.,Machrouhi, Fouzia
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- Generation and trapping of isobenzofuran intermediates formed in the coupling of Fischer carbene complexes and o-alkynylbenzoyl derivatives
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(equation presented) The coupling of o-alkynylbenzoyl derivatives with carbene complexes has been investigated. The reaction initially affords isobenzofuran derivatives, which convert to alkylidenephthalan derivatives or can be trapped by various dienophi
- Jiang, Delu,Herndon, James W.
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- Palladium catalyzed alkynylation of aryl halides (Sonogashira reaction) in water
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The palladium catalyzed alkynylation of aryl halides (Sonogashira reaction) has been achieved in pure water without any additives or phase transfer catalysts. The reaction, which requires only 0.5 mol % of Pd(PPh 3)4 catalyst, is rem
- Bhattacharya, Santanu,Sengupta, Saumitra
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- Design and Synthesis of Fused Pyridine Building Blocks for Automated Library Generation
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We demonstrate that a diboration-electrocyclization sequence provides access to a range of pyridine-fused, small-molecule boronic ester building blocks, and that these are amenable to high-throughput synthesis leading to biaryl and ether-linked compound libraries. Moreover, the implementation of an integrated physicochemical and ADME profiling workflow allows accelerated design of novel lead compounds for application in drug-discovery projects.
- Mora-Radó, Helena,Czechtizky, Werngard,Méndez, María,Harrity, Joseph P. A.
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supporting information
p. 328 - 334
(2020/12/17)
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- Synthesis of Fused Pyrimido[1,6- a ]indolones via Rhodium(III)-Catalyzed Cascade Annulations
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A novel method for the synthesis of fused pyrimido[1,6- a ]-indolone derivatives by annulation of 2-alkynylaryl aldehydes/2-alkynyl arylidene ketones with N -(pivaloyloxy)-1 H -indole-1-carboxamide catalyzed by rhodium has been accomplished. The reaction proceeds through C-H activation based annulation with alkyne moiety followed by addition of nitrogen on to aldehyde/activated alkene to give the products in moderate to good yields. Highly fluorescent dipyrrinone analogues could be synthesized from the derived products.
- Raji Reddy, Chada,Bodasu, Srinivas,Mallesh, Kathe,Prapurna, Y. Lakshmi
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p. 1127 - 1136
(2020/10/29)
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- Radical Cascade Bicyclization/Aromatization of 1,7-Enynes with 1,3-Dicarbonyl Compounds towards 2,3-Dihydro-1H-cyclopenta[a]naphthalenes
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An Ag-catalyzed radical cascade bicyclization/aromatization of C-linked 1,7-enynes with 1,3-dicarbonyls has been achieved, providing a step- and atom-economy approach for the construction of 2,3-dihydro-1H-cyclopenta[a]naphthalenes, an important structural scaffold existed in biologically active compounds. From this transformation, structurally diverse 2,3-dihydro-1H-cyclopenta[a]naphthalenes were obtained in moderate to good yields with high regioselectivity. Moreover, the further product derivatizations were also exemplified. (Figure presented.).
- Cai, Tao,Chen, Jianhui,Chen, Xinyu,Gao, Yuzhen,Li, Peiqin,Ni, Yuqi,Shen, Runpu,Sun, Tao,Wu, Chunlei,Xu, Huiting,Xu, Yanfei,Zhang, Zhebing
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supporting information
p. 3750 - 3755
(2021/07/09)
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- N-Iodosuccinimide-Mediated Dimerization of 2-Alkynylnaphthols: A Highly Diastereoselective Construction of Bridged Polycyclic Compounds via Vinylidene ortho-Quinone Methide Intermediate
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An unprecedented highly diastereoselective dimerization of 2-alkynylnaphthols is presented to furnish bridged polycyclic compounds containing a bicyclo[3.2.1]octane moiety with good to excellent yields. The reaction proceeded under mild conditions using N-iodosuccinimide as a promoter, simultaneously constructing one new C-O bond and two new C-C bonds. A tetra-substituted vinylidene ortho-quinone methide intermediate was likely involved, and the steric hindrance of substituents played a critical role in this transformation.
- Tan, Yu,Zhao, Zhengxing,Chen, Zhili,Huang, Shengli,Jia, Shiqi,Peng, Lei,Xu, Da,Qin, Wenling,Yan, Hailong
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supporting information
p. 4461 - 4466
(2020/06/03)
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- Stereospecific Synthesis of (Z,Z)-Isobenzofurans via Radical-Enabled Cleavage of C(sp3)?C(sp3) and C(sp2)-Halogen Bonds
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A novel radical-induced annulation/1,8-halosulfonylation of β-alkynyl ketones with haloaryl diazonium tetrafluoroborates and DABCO.bis(sulfur dioxide) was first achieved via the cleavage/recombination of C(sp3)?C(sp3) and C(sp2)-halogen bonds, from which 47 examples of sulfone-containing 1,3-dimethylene-substituted (Z,Z)-isobenzofurans as single stereoisomers were synthesized in generally good yields. This multicomponent pathway is proposed to proceed through the in-situ generation of arylsulfonyl radicals, followed by selective radical addition-cyclization and ring-opening of the cyclopropyl unit as well as C(sp2)-halogen bond cleavage, resulting in the consecutive construction of three new chemical bonds, including C?S, C?O and C-halogen bonds. (Figure presented.).
- Huang, Min-Hua,Shi, Hao-Nan,Zhu, Chi-Fan,He, Chun-Lan,Hao, Wen-Juan,Tu, Shu-Jiang,Jiang, Bo
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supporting information
p. 5340 - 5345
(2019/11/14)
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- Palladium-Catalyzed Dialkylation of C-C Triple Bonds: Access to Multi-Functionalized Indenes
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A palladium-catalyzed dialkylation of 1,3-dien-5-ynes was developed using alkenyl double bonds as the initiator and terminator for the synthesis of functionalized indene derivatives. The reactions were performed under mild reaction conditions, affording the corresponding multi-substituted indene derivatives in high efficiency via unprecedented 5-endo cyclization and alkylation processes. It was found that the substituent location at the alkenyl double bond was essential for the chemoselective synthesis of the indene and naphthalene derivatives, respectively.
- Liu, Xiao-Wei,Li, Shu-Sen,Dai, Dong-Ting,Zhao, Meng,Shan, Cui-Cui,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 3696 - 3700
(2019/05/24)
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- A Mild and Regioselective Synthesis of α-Fluoroketones via Gold and Selectfluor Partnership
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An efficient, mild and rapid synthesis of α-fluoroketones has been developed, via a fruitful association between gold and Selectfluor starting from aldehyde-yne and alkynylaryl ketone derivatives. Several functionalized and synthetically highly valuable α-fluoroketones (21 compounds, up to 92%) were isolated in good to excellent yields via a remarkable regioselective oxyfluorination reaction in EtOH/H2O at room temperature. We have shed some light on parts of the mechanism by reacting diphenylacetylene and aldehyde-yne with or without Selectfluor. The reaction most presumably occurs via a sequential gold-catalyzed regioselective hydration followed by the α-fluorination reaction, but the presence of aldehyde moiety is crucial for the reactivity of alkyne function. The fluoroketones were efficiently transformed to 4-fluoroisoquinolines (9 compounds, 82–95%) of high pharmaceutical interest. (Figure presented.).
- Chen, Xi,Martini, Sophie,Michelet, Véronique
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p. 3612 - 3618
(2019/07/10)
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- Synthesis of Fluorescent Azafluorenones and Derivatives via a Ruthenium-Catalyzed [2 + 2 + 2] Cycloaddition
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An original and mild synthetic route for the preparation of novel azafluorenones and derivatives via a ruthenium-mediated [2 + 2 + 2] cycloaddition of α,ω-diynes and cyanamides has been developed. This atom-economical catalytic process demonstrated remarkable regioselectivities to access fluorescent azafluorenone derivatives. The photophysical properties of azafluorenone derivatives have been evaluated, and photoluminescence phenomena at solid and liquid states have been highlighted.
- Ye, Fei,Tran, Christine,Jullien, Ludovic,Le Saux, Thomas,Haddad, Mansour,Michelet, Véronique,Ratovelomanana-Vidal, Virginie
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supporting information
p. 4950 - 4953
(2018/08/24)
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- An Oxyboration Route to a Single Regioisomer of Borylated Dihydrofurans and Isochromenes
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An oxyboration reaction that employs B-O σ bonds as addition partners to C-C π bonds to form borylated dihydrofurans and isochromenes has been developed. By nature of the mechanism, the reaction produces exclusively one borylated regioisomer, in contrast to and/or complementary to alternative routes that produce these borylated heterocycles via C-H activation. Access to the borylative heterocyclization route is demonstrated from alcohols directly or from a hydroboration-oxyboration sequence starting from the corresponding ketone, forming the heterocyclic core and installing the boron in one synthetic step. Catechol boronates were directly used as coupling partners in the in situ Suzuki cross-coupling reactions without transesterification to pinacol boronates.
- Tu, Kim N.,Gao, Chao,Blum, Suzanne A.
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supporting information
p. 11204 - 11217
(2018/08/03)
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- Bioinspired Total Synthesis of (±)-Chaetophenol C Enabled by a Pd-Catalyzed Cascade Cyclization
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A novel Pd(II)-catalyzed cascade reaction has been developed that consists of a highly regio- and stereoselective oxa [4 + 2] cycloaddition reaction of o-alkynylbenzaldehydes and an intramolecular carboxylic group quenching of the in situ generated oxonium ion. This new reaction provides a one-step construction of the tetracyclic core structure of chaetophenol C from two simple starting materials. The developed chemistry was successfully applied to the first total synthesis of chaetophenol C and dozens of its analogues.
- Li, Yun,Zhang, Qingyu,Wang, Hongyu,Cheng, Bin,Zhai, Hongbin
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supporting information
p. 4387 - 4390
(2017/08/23)
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- Highly selective construction of medium-sized lactams by palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes
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A novel palladium-catalyzed intramolecular hydroaminocarbonylation of aminoalkynes has been developed. This direct and operationally simple protocol provides a rapid and reliable approach to a diverse array of valuable seven-and eight-membered lactams with high chemoselectivity and regioselectivity. The high selectivity might be attributed to rational tuning the electronic nature of the amine moiety and the palladium catalyst which enabled this transformation to proceed in the absence of acidic or any other additives under fairly mild reaction conditions. This method paves the way for the synthesis of medium-sized lactams.
- Hu, Yue,Huang, Hanmin
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supporting information
p. 5070 - 5073
(2017/11/07)
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- Catalytic Asymmetric 1,3-Dipolar Cycloaddition/Hydroamination Sequence: Expeditious Access to Enantioenriched Pyrroloisoquinoline Derivatives
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A three-step reaction sequence has been developed to prepare a variety of enantioenriched pyrroloisoquinoline derivatives. The process involves a catalytic asymmetric azomethine ylide 1,3-dipolar cycloaddition followed by an intramolecular AuI-catalyzed alkyne hydroamination and enamine reduction.
- Molina, Alba,Pascual-Escudero, Ana,Adrio, Javier,Carretero, Juan C.
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supporting information
p. 11238 - 11246
(2017/10/27)
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- Efficient Pathway for the Preparation of Aryl(isoquinoline)iodonium(III) Salts and Synthesis of Radiofluorinated Isoquinolines
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Iodonium compounds play a pivotal role in18F-fluorination of radiopharmaceuticals containing non-activated arenes. However, preparation of these species is limited to oxidation conditions or exchange with organometallics that are prepared from aryl halides. Herein we describe a novel “one-pot” process to assemble aryl(isoquinoline)iodonium salts in 40–94 % yields from mesoionic carbene silver complex and Aryl-I-Py2(OTf)2. The method is general, practical, and compatible with well-functionalized molecules as well as useful for the preparation of a wide range of18F-labeled isoquinolines resulting in up to 92 % radiochemical conversion. As proof of concept, a fluorinated isoquinoline alkaloid,18F-aspergillitine is prepared in 10 % isolated radiochemical yield from the corresponding phenyl(aspergillitine)iodonium salt.
- Yuan, Zheliang,Cheng, Ran,Chen, Pinhong,Liu, Guosheng,Liang, Steven H.
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supporting information
p. 11882 - 11886
(2016/11/17)
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- Radical Cascade Cyclization: Reaction of 1,6-Enynes with Aryl Radicals by Electron Catalysis
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The radical cascade cyclization of various 1,6-enynes with aryl radicals by electron catalysis under metal-free reaction conditions was explored. Readily available anilines were used as radical precursors, and the reactions proceeded in the absence of any transition metal. These cascades comprise three C–C bond formations, which provide polycyclic structures with extended π-systems. The photophysical properties of some of these novel compounds were investigated, and a plausible reaction mechanism is proposed.
- Xuan, Jun,Gonzalez-Abradelo, Dario,Strassert, Cristian Alejandro,Daniliuc, Constantin-Gabriel,Studer, Armido
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supporting information
p. 4961 - 4964
(2016/10/26)
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- Synthesis of Functionalized 1H-Isochromene Derivatives via a Au-Catalyzed Domino Cycloisomerization/Reduction Approach
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A Au-catalyzed versatile and efficient access to 1H-isochromenes is reported. The efficiency of the [AuCl2(Pic)] complex (1-5 mol %) was demonstrated and allowed a domino cycloisomerization/reduction reaction process starting from a wide range of functionalized ortho-alkynylbenzaldehydes and one example of ortho-alkynylpyridinylaldehyde. The smooth reaction conditions were amenable to aryl- and alkyl-substituted alkynyl derivatives, as well as functionalized halogen and ether moieties, leading to a chemo- and regioselective 6-endo-cyclization with good to excellent yields.
- Tomás-Mendivil, Eder,Starck, Jéro?me,Ortuno, Jean-Claude,Michelet, Véronique
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supporting information
p. 6126 - 6129
(2016/01/09)
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- Traceless directing groups in radical cascades: From oligoalkynes to fused helicenes without tethered initiators
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We report the first example of a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by propargyl OR moiety. Radical translocations lead to the boomerang return of the radical center to the site of initial attack where it assists the elimination of the directing functionality via β-scission in the last step of the cascade. The Bu3Sn moiety continues further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions. (Chemical Equation Presented).
- Pati, Kamalkishore,Gomes, Gabriel Dos Passos,Harris, Trevor,Hughes, Audrey,Phan, Hoa,Banerjee, Tanmay,Hanson, Kenneth,Alabugin, Igor V.
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supporting information
p. 1165 - 1180
(2015/02/05)
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- Gold(I)-catalyzed cycloisomerizations and alkoxycyclizations of ortho-(alkynyl)styrenes
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Indenes and related polycyclic structures have been efficiently synthesized by gold(I)-catalyzed cycloisomerizations of appropriate ortho-(alkynyl)styrenes. Disubstitution at the terminal position of the olefin was demonstrated to be essential to obtain products originating from a formal 5-endo-dig cyclization. Interestingly, a complete switch in the selectivity of the cyclization of o-(alkynyl)-a-methylstyrenes from 6-endo to 5-endo was observed by adding an alcohol to the reaction media. This allowed the synthesis of interesting indenes bearing an all-carbon quaternary center at C1. Moreover, dihydrobenzo[a]fluorenes can be obtained from substrates bearing a secondary alkyl group at the β-position of the styrene moiety by a tandem cycloisomerization/1,2-hydride migration process. In addition, diverse polycyclic compounds were obtained by an intramolecular gold-catalyzed alkoxycyclization of o-(alkynyl)styrenes bearing a nucleophile in their structure. Finally, the use of a chiral gold complex allowed access to elusive chiral 1H-indenes in good enantioselectivities.
- Sanjun, Ana M.,Rashid, Muhammad A.,Garca-Garca, Patricia,Martnez-Cuezva, Alberto,Fernndez-Rodrguez, Manuel A.,Rodrguez, Flix,Sanz, Roberto
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supporting information
p. 3042 - 3052
(2015/02/05)
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- Gold catalysis: β-ketonaphthalenes via molecular gymnastics of 1,6-diyne-4-en-3-ols
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1,6-Diyne-4-en-3-ols with one terminal alkyne were applied as test substrates for a possible dual catalyzed cyclization. Instead of a dual catalysis cycle, naphthyl ketone derivatives were obtained as single products. The regioselectivity of the obtained products is unprecedented. Instead of the expected naphthyl ketones bearing the keto group in the α-position, the keto group is positioned in the ss-position of the naphthyl skeleton by a complex rearrangement of the starting materials. Copyright
- Lauterbach, Tobias,Arndt, Sebastian,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 1755 - 1761
(2013/07/11)
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- [3,3]-Sigmatropic rearrangement step in the gold-catalyzed cyclization of allyl-(ortho-alkinylphenyl)methyl ethers
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The gold-catalyzed conversion of allyl-(ortho-alkynylphenyl)methyl ethers was investigated, and allylated isochromenes were obtained. An optimization of the catalysis conditions with respect to different phosphane and carbene ligands on gold, different counterions, and different solvents was conducted. Subsequently, the scope and limitations of this reaction were investigated with 21 substrates. The mechanistic studies show an allylic inversion, as supported by NMR data and an X-ray crystal structure analysis, as well as an intermolecular reaction, as determined by crossover experiments. There is no competition of protodeauration even in the presence of water. All these observations differ from other related conversions and clearly indicate product formation by a [3,3]sigmatropic rearrangement in the step forming the new C-C bond. The Golden Key: Allylic inversion and crossover experiments reveal a sigmatropic rearrangement as a key step in the gold-catalyzed intramolecular allyl transfer in ortho-alkinyl benzyl allyl ethers. Copyright
- Ackermann, Martin,Bucher, Janina,Rappold, Melissa,Graf, Katharina,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 1786 - 1794
(2013/09/02)
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- Antimycobacterial activity evaluation, time-kill kinetic and 3D-QSAR study of C-(3-aminomethyl-cyclohexyl)-methylamine derivatives
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A series of C-(3-aminomethyl-cyclohexyl)-methylamine derivatives were synthesized and evaluated for their antitubercular activity. Some of the compounds exhibited potent activity against Mycobacterium tuberculosis H37Rv. One of the compound having t-butyl at para position of the benzene ring showed excellent activity even better than the standard drug ethambutol with MIC value 1.1 ± 0.2 μM. The time-kill kinetics study of two most active compounds showed rapid killing of the M. tuberculosis within 4 days. Additionally atom-based quantitative structure-activity relationship (QSAR) model was developed that gave a statistically satisfying result (R2) = 0.92, Q2 = 0.75, Pearson-R = 0.96 and effectively predicts the anti-tuberculosis activity of training and test set compounds.
- Kumar, Deepak,Raj, K. Kranthi,Bailey, Maiann,Alling, Torey,Parish, Tanya,Rawat, Diwan S.
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supporting information
p. 1365 - 1369
(2013/03/14)
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- Silver(I)-catalyzed addition-cyclization of alkyne-functionalized azomethines
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AgOTf can catalyze an addition-cyclization tandem between alkyne-azomethine and a nucleophile such as ketone, nitroalkane, water, and terminal alkyne to give a polycyclic amide via six-exo-trig selectivity.
- Liu, Yuchen,Zhen, Wencui,Dai, Wei,Wang, Fen,Li, Xingwei
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supporting information
p. 874 - 877
(2013/03/28)
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- Iodide-catalyzed halocyclization/cycloaddition/elimination cascade reaction
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An iodocyclization reaction of o-alkynylphenyl carboxaldehydes is reported that is truly catalytic with respect to the electrophilic iodine source. With a combination of tetrabutylammonium iodide (TBAI), Oxone as non-nucleophilic and easy to handle co-oxidant, and fluorinated protic solvents, highly substituted 1-naphthalenones could be prepared in high yields of up to 91%.
- Kloeckner, Ulrich,Finkbeiner, Peter,Nachtsheim, Boris J.
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p. 2751 - 2756
(2013/04/23)
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- Domino hydroarylation-cyclization reaction: One-pot synthesis of indane-fused 3,4-dihydrocoumarins
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A tin(II) triflate-catalyzed domino hydroarylation-cyclization reaction has been developed to access a wide-variety of methyleneindane-fused 3,4-hydrocoumarins. A judiciously selected bi-functional Lewis acidic catalyst has been successfully applied to promote two ring-closing events as a single-pot operation.
- Joo, Jin Hyuck,Youn, So Won
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supporting information
p. 559 - 568
(2013/05/09)
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- 1,3-Dipolar cycloaddition of 4-platinumisochromenyliums with an olefin and tandem insertion into benzylic C-H bonds
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Isochromenylium-4-ylplatinum(ii) species, generated from 1-(2-alkynylphenyl)hex-5-en-1-ones and Pt(ii), reacted with a pendant olefin via [3+2] cycloaddition to form tetracyclic Pt-carbene complexes, which underwent C-H insertion with a benzyloxy group at δ or ε positions to give highly complex polycycles, which are otherwise hard to access.
- Kim, Ji Hee,Ray, Devalina,Hong, Chang Seop,Han, Jin Wook,Oh, Chang Ho
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supporting information
p. 5690 - 5692
(2013/07/05)
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- Grignard reagent/CuI/LiCl-mediated stereoselective cascade addition/cyclization of diynes: A novel pathway for the construction of 1-methyleneindene derivatives
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Diynes containing a cyclopropane group smoothly undergo a novel intramolecular and stereoselective cascade addition/cyclization reaction to produce the corresponding 1-methyleneindene derivatives in moderate to good yields. This interesting transformation is mediated by Grignard reagent/CuI with LiCl as an additive under mild conditions. The obtained product can easily be further functionalized through cyclopropyl ring opening. A plausible reaction mechanism has also been presented on the basis of deuterium labeling and control experiments. Diyne cyclization: Diynes containing a cyclopropane group undergo a novel intramolecular and stereoselective cascade addition/cyclization reaction to produce the corresponding 1-methyleneindene derivatives (see scheme). The transformation proceeds under mild conditions and is promoted by a combination of Grignard reagent Copyright
- Li, De-Yao,Wei, Yin,Shi, Min
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supporting information
p. 15682 - 15688
(2013/11/19)
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- On water: Silver-catalyzed domino approach for the synthesis of benzoxazine/oxazine-fused isoquinolines and naphthyridines from o-alkynyl aldehydes
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An operationally simple domino approach for the silver-catalyzed synthesis of oxazine/benzoxazine-fused isoquinolines 5a-q and naphthyridines 6a-v by the reaction of o-alkynyl aldehydes 3a-aa with amines having embedded nucleophiles 4a-d under mild reacti
- Verma, Akhilesh K.,Choudhary, Deepak,Saunthwal, Rakesh K.,Rustagi, Vineeta,Patel, Monika,Tiwari, Rakesh K.
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p. 6657 - 6669
(2013/07/26)
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- Chiral counteranion-directed silver-catalyzed asymmetric synthesis of 1,2-dihydroisoquinolines by Friedel-Crafts alkylation reactions
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The reaction of ortho-alkynylaryl aldimines and indoles catalyzed by a silver binol-derived phosphate was realized to afford a series of enantioenriched 1,2-dihydroisoquinolines in moderate to good yields and ee. An interesting phenomenon that highly enantioenriched products could be obtained from their lower ee form by silica gel column chromatography was observed, providing an easy access to the enantiopure form of the product.
- Zhang, Jun-Wei,Xu, Zhe,Gu, Qing,Shi, Xiao-Xin,Leng, Xue-Bing,You, Shu-Li
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supporting information; experimental part
p. 5263 - 5268
(2012/08/08)
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- Versatile synthesis of isoquinolines and isochromenes by Pd-catalyzed oxidative carbonylation of (2-alkynyl)benzylideneamine derivatives
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Isoquinoline-4-carboxylic esters 3 and isochromene-4-carboxylic esters 4 have been conveniently prepared by direct PdI2-catalyzed oxidative heterocyclization/alkoxycarbonylation of readily available (2- alkynylbenzylidene)amine derivatives. In particular, (2-alkynylbenzylidene) (tert-butyl)amines 2 selectively afforded isoquinoline derivatives 3 by N-cyclization, whereas N-(2-alkynylbenzylidene)-N′-phenylhydrazines 5 led to the formation of isochromenes 4 through O-cyclization ensuing from water attack on the imino group of the substrate. Reactions were carried out in alcoholic solvents at 80-100 °C and under 20-80 atm (at 25 °C) of a 4:1 mixture of CO/air, in the presence of PdI2 (2-10 mol-%) in conjunction with KI (KI/PdI2 molar ratio = 10). In the case of imines 2, the use of a dehydration agent, such as trialkyl orthoformate, was necessary to obtain satisfactory yields of isoquinolines 3.
- Gabriele, Bartolo,Veltri, Lucia,Maltese, Vito,Spina, Rosella,Mancuso, Raffaella,Salerno, Giuseppe
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experimental part
p. 5626 - 5635
(2011/11/29)
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- NHC-catalyzed oxidative cyclization reactions of 2-alkynylbenzaldehydes under aerobic conditions: Synthesis of O-Heterocycles
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Chemical equations presented. An NHC-catalyzed, regio- and stereoselective oxidative cyclization of o-alkynylbenzaldehydes bearing an unactivated alkyne moiety as an internal electrophile has been developed to afford phthalides and isocoumarins. A single organocatalytic system enabled two sequential C-O bond formations to take place in an atom economical manner via highly efficient dual activation. Molecular oxygen in air could be utilized as a source of an oxygen atom for the oxidation of aldehydes to the corresponding benzoic acids under our newly developed reagent system.
- Park, Jong Hyub,Bhilare, Sachin V.,Youn, So Won
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supporting information; experimental part
p. 2228 - 2231
(2011/07/09)
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- Gold-catalyzed cascade friedel-crafts/furan-yne cyclization/heteroenyne metathesis for the highly efficient construction of phenanthrene derivatives
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A rapid access to highly substituted phenanthrenyl ketones through gold-catalyzed cyclization of 1,6-diyn-4-en-3-ols with furans has been developed. Gold catalysts are effective to catalyze three cascade processes involving Friedel-Crafts/furan-yne cyclization/heteroenyne metathesis through C-O bond and alkyne activation. This method offers several advantages such as high selectivities and easily accessible starting materials.
- Chen, Yifeng,Li, Guijie,Liu, Yuanhong
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supporting information; experimental part
p. 392 - 400
(2011/04/22)
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- Regio- and stereoselective construction of highly functionalized 3-benzazepine skeletons through ring-opening cycloamination reactions catalyzed by Gold
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Ring size under control: Highly functionalized 1-amino- or 1-hydroxy-1H-benzo[d]azepines have been prepared through a gold-catalyzed cyclization of (o-alkynyl)phenyl aziridines with heteronucleophiles. After removal of the phthalimido group, the products can be further transformed into 1H-benzo[d]azepin-1-ones (see scheme; IBX=2-iodoxybenzoic acid, Phth=pthalimido).
- Du, Xiangwei,Yang, Shuang,Yang, Jingyu,Liu, Yuanhong
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supporting information; experimental part
p. 4981 - 4985
(2011/06/17)
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- Gold(I)- and Yb(OTf)3-Cocatalyzed rearrangements of epoxy alkynes: Transfer of a carbonyl group in a five-membered carbocycle
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We report here the intramolecular reactions between α,β-epoxy ketones and alkynes cocatalyzed by gold(I) and Yb(OTf)3. This new catalytic system based on a combination of gold(I) and Yb (OTf)3 allows facile transformation of epoxy alkynes to give novel indene derivatives in moderate to good yields under mild conditions. Moreover, we describe here the first observation of a transfer of a carbonyl group in a five-membered carbocycle during gold-catalyzed reactions. This proposed mechanism is corroborated by isotope-labeling experiments (D and 13C). Furthermore, the probable role of each catalyst in this interesting domino reaction has been examined by 31P NMR experiments. The utilization of gold catalysts combined with rareearth metal salts offers a new concept for the design of catalyst combinations for domino or cascade reactions.
- Dai, Lun-Zhi,Shi, Min
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supporting information; experimental part
p. 2496 - 2502
(2010/06/20)
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- Gold(I) - Catalyzed domino reaction of aziridinyl alkynes
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Chemical Equation Presented Aziridinyl alkynes strike gold: A novel gold(I)-catalyzed domino transformation of aziridinyl alkynes with arenes to construct 1,2,3,4-tetrahydroisoquinoline and 3,4-dihydroisoquinoline structural motifs (see scheme), especially sterically congested Syn-3,4-disubsti contzonetuted 1,2,3,4-tetrahydroisoquinolines, is described. A plausible mechanism proceeding through a benzylic cation is given based upon deuterium-labeling and control experiments as well as the observed diastereoselectivities.
- Zhang, Zhen,Shi, Min
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supporting information; experimental part
p. 7725 - 7729
(2010/09/10)
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- Gold(I)-catalyzed enantioselective synthesis of functionalized indenes
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Chemical Equation Presented Can you dig it? An asymmetric synthesis of functionalized 1H-indenes from easily available ortho-(alkynyl)styrene derivatives under mild reaction conditions has been achieved. The reactions proceed through an unprecedented and selective 5-endo-dig gold(l)-catalyzed cycloisomerization or alkoxycyclization, if water or an alcohol is present (see scheme).
- Martinez, Alberto,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Rodriguez, Felix,Sanz, Roberto
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supporting information; experimental part
p. 4633 - 4637
(2010/08/22)
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- Rapid access to 1-methyleneindenes via palladium-catalyzed tandem reactions of 1-(2,2-dibromovinyl)-2-alkynylbenzenes with arylboronic acids
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A novel and efficient route for the synthesis of 1-methyleneindenes via palladium-catalyzed tandem reactions of 1-(2,2-dibromovinyl)-2-alkynylbenzene with arylboronic acids is described. This reaction proceeded under mild conditions with high efficiency and excellent selectivity. The Royal Society of Chemistry 2010.
- Ye, Shengqing,Yang, Xiaodi,Wu, Jie
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supporting information; scheme or table
p. 2950 - 2952
(2010/08/05)
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- Halocyclization of o-(alkynyl)styrenes. Synthesis of 3-halo-1H-indenes
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o-(Alkynyl)styrenes undergo halocarbocyclization processes via a 5-endo-dig ring closure. By this strategy an efficient synthesis of 3-halo-1H-indene derivatives has been developed.
- Sanz, Roberto,Martinez, Alberto,Garcia-Garcia, Patricia,Fernandez-Rodriguez, Manuel A.,Rashid, Muhammad A.,Rodriguez, Felix
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supporting information; experimental part
p. 7427 - 7429
(2010/11/18)
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- One-pot concise syntheses of benzimidazo[2,1-a]isoquinolines by a microwave-accelerated tandem process
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Direct, efficient syntheses of the benzimidazo[2,1-a]isoquinoline ring system have been achieved with 2-bromoarylaldehydes, terminal alkynes, and 1,2-phenylenediamines by a microwave-accelerated tandem process in which a Sonogashira coupling, 5-endo cyclization, oxidative aromatization, and 6-endo cyclization can be performed in a single synthetic operation.
- Okamoto, Noriko,Sakurai, Keisuke,Ishikura, Minoru,Takeda, Kei,Yanada, Reiko
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scheme or table
p. 4167 - 4169
(2009/10/26)
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- Synthesis of substituted 6-imino-2-piperidinones by Rh-catalyzed [4+2] annulation of 4-alkynals with carbodiimides
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Synthesis of substituted 6-imino-2-piperidinones has been achieved by cationic rhodium(I)/dppp complex-catalyzed [4+2] annulations of various 4-alkynals with carbodiimides at room temperature. The reactions of benzene-linked 4-alkynals (2-alkynylbenzaldehydes) and carbodiimides also proceeded at room temperature, affording the corresponding 6-imino-2-piperidinones.
- Tanaka, Ken,Mimura, Marina,Hojo, Daiki
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experimental part
p. 9008 - 9014
(2009/12/22)
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- PtII-catalyzed synthesis of 9-oxabicyclo[3.3.1]nona-2,6-dienes from 2-alkynyl-1-carbonylbenzenes and allylsilanes by an allylation/annulation cascade
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(Chemical Equation Presented) Platinum is key: A new catalytic synthesis of 9-oxabicyclo[3.3.1]nona-2,6-dienes from readily available 2-alkynyl-1- carbonylbenzenes, allylsilanes, and water is reported (see scheme). This reaction sequence is proposed to proceed through a series of three reactions, including allylation of the carbonyl group, hydroalkoxylation of the alkyne, and a new eneoxonium annulation.
- Bhunia, Sabyasachi,Wang, Kuo-Chang,Liu, Rai-Shung
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supporting information; experimental part
p. 5063 - 5066
(2009/03/11)
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- Gold catalysis: Synthesis of 3-acylindenes from 2-alkynylaryl epoxides
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A series of 2-alkynylaryl epoxides were prepared by a sequence of Sonogashira coupling, Wittig olefination and epoxidation or a Darzens' glycid ester synthesis. The conversion of these substrates with gold(I) catalysts furnished 3-acylindenes and, in occa
- Hashmi, A. Stephen K.,Buehrle, Miriam,Salathe, Ralph,Bats, Jan W.
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supporting information; experimental part
p. 2059 - 2064
(2009/08/07)
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- Indium(III)-catalyzed tandem reaction with alkynylbenzaldehydes and alkynylanilines to heteroaromatic compounds
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(Chemical Equation Presented) Starting from ortho-alkynylbenzaldehydes and ortho-alkynylanilines, In(OTf)3-catalyzed synthesis of ring-condensed heteroaromatic compounds was developed via a domino intramolecular nucleophilic attack/intermolecular cycloaddition/dehydration reaction.
- Yanada, Reiko,Hashimoto, Kana,Tokizane, Rie,Miwa, Yoshihisa,Minami, Hideki,Yanada, Kazuo,Ishikura, Minoru,Takemoto, Yoshiji
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p. 5135 - 5138
(2008/09/21)
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- Enantioselective synthesis of spirocyclic benzopyranones by rhodium-catalyzed intermolecular [4+2] annulation
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(Chemical Equation Presented) Rounding things off: A cationic Rh I/(R,R)-walphos complex catalyzes an enantioselective [4+2] annulation of 2-alkynylbenzaldehydes with cyclic electron-deficient carbonyl compounds at room temperature (see scheme, R3=3,5-(F 3C)2C6H3, X=C or N). Enantioenriched spirocyclic benzopyranones and isatin derivatives are obtained in high yield (up to 97%) and high enantioselectivity (up to >99%).
- Hojo, Daiki,Noguchi, Keiichi,Hirano, Masao,Tanaka, Ken
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body text
p. 5820 - 5822
(2009/03/11)
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- Syntheses of isochromenes and naphthalenes by electrophilic cyclization of acetylenic arenecarboxaldehydes
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Highly substituted IH-isochromenes, isobenzofurans, and pyranopyridines can be prepared by allowing o-(1-alkynyl)arenecarboxaldehydes and ketones to react with I2, ICl, NIS, Br2, NBS, p-O2NC 6H4SCl, or PhSeBr and various alcohols or carbon-based nucleophiles at room temperature. Naphthyl ketones and iodides are also readily prepared by the reaction of 2-(1-alkynyl)arenecarboxaldehydes with I2 and simple olefins or alkynes.
- Yue, Dawei,Della Ca, Nicola,Larock, Richard C.
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p. 3381 - 3388
(2007/10/03)
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- The reaction of o-alkynylarene and heteroarene carboxaldehyde derivatives with iodonium ions and nucleophiles: A versatile and regioselective synthesis of 1H-isochromene, naphthalene, indole, benzofuran, and benzothiophene compounds
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The reaction of o-alkynyl-benzaldehydes 1 with different alcohols, silylated nucleophiles 5, electronrich arenes 10, and heteroarenes 12 in the presence of the reagent IPy2BF4, at room temperature, gave functionalized 4-iodo-1H-isochromenes 2, 6, 11, and 13 in a regioselective manner. When alkynes 16 and alkenes 19 and 20 were used as nucleophiles, a regioselective benzannulation reaction took place to form 1-iodonaphthalenes 17 and 1-naphthyl ketones 18, respectively. Moreover, the latter process has been adapted to accomplish the synthesis of indole, benzofuran, and benzothiophene derivatives (23, 27, and 28, respectively). The three patterns of reactivity observed for the o-alkynylbenzaldehyde derivatives with IPy2BF 4 stem from a common iodinated isobenzopyrylium ion intermediate, A, that evolves in a different way depending on the nucleophile present in the reac-tion medium. A mechanism is proposed and the different reaction pathways observed as a function of the type of nucleophile are discussed. Furthermore, the reaction of the o-hexynyl-benzaldehyde 1b with styrene was monitored by NMR spectroscopy. Compound III, a resting state for the common intermediate in the absence of acid, has been isolated. Its evolution in acid media has been also tested, thereby providing support to the proposed mechanism.
- Barluenga, Jose,Vazquez-Villa, Henar,Merino, Isabel,Ballesteros, Alfredo,Gonzalez, Jose M.
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p. 5790 - 5805
(2008/03/11)
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