- 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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- Tunable Synthesis of Indeno[1,2- c]furans and 3-Benzoylindenones via FeCl3-Catalyzed Carbene/Alkyne Metathesis Reaction of o-Alkynylbenzoyl Diazoacetates
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An efficient synthesis of indeno[1,2-c]furan and 3-benzoylindenone derivatives through a FeCl3-catalyzed carbene/alkyne metathesis reaction of o-alkynylbenzoyl diazoacetates is presented. Mechanistically, the key intermediate, vinyl iron carbene, is formed by 5-exo-dig carbocyclization and terminated with a formal [3 + 2] cycloaddition or carbonylation. To the best of our knowledge, this is the first example in which FeCl3 is used as a catalyst for a carbene/alkyne metathesis reaction. Finally, derivatization reactions were carried out to showcase the value of the products.
- Li, Bin,Shen, Nana,Yang, Yujie,Zhang, Xinying,Fan, Xuesen
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supporting information
p. 388 - 393
(2021/01/13)
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- Light-Enabled Radical 1,4-Aryl Migration Via a Phospho-Smiles Rearrangement
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Rearrangement reactions in organic chemistry are attractive strategies to build efficiently complex scaffolds, in just one step, from simple starting materials. Among them, aryl migrations are certainly one of the most useful and straightforward rearrangement for building attractive carbon-carbon bonds. Of note, anionic aryl migration reactions have been largely described compared to their radical counterparts. Recently, visible-light catalysis has proven its efficiency to generate such radical rearrangements due to the concomitant loss of a particle (often CO2 or SO2), which is the driving-force of the reaction. Here, we disclose a Smiles-type rearrangement, triggered by a phosphorus-containing unit (arylphosphoramidate), therefore called "phospho-Smiles"rearrangement, allowing a Csp2-Csp2 bond formation thanks to a 1,4-aryl migration reaction. In addition, combining this approach with a radical hydroamination/amination reaction produces an amination/phospho-Smiles cascade particularly attractive, for instance, to investigate the synthesis of the phthalazine core, a scarcely described scaffold of interest for medicinal chemistry projects.
- De Abreu, Maxime,Belmont, Philippe,Brachet, Etienne
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p. 3758 - 3767
(2021/02/01)
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- Hydrophilic Pd-phosphines catalyzed one-pot synthesis of substituted isoquinolines, furopyridines and thienopyridines in aqueous medium
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A first example of simple and efficient hydrophilic Pd-phosphine complexes catalyzed one-pot three-component reaction of ortho-bromo aldehydes, terminal alkynes and ammonium acetate proceeds through the tandem coupling-imination-annulation path for the synthesis of substituted isoquinolines, furopyridines and thienopyridines in good to excellent yields in green aqueous medium at mild temperature was described.
- Guguloth, Veeranna,Thirukovela, Narasimha Swamy,Balaboina, Ramesh,Paidakula, Suresh,Vadde, Ravinder
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supporting information
p. 297 - 299
(2019/01/04)
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- Silver-Catalysed Domino Approach to 1,3-Dicarbo-Substituted Isochromenes
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We report herein the first example of the silver triflate catalysed synthesis of 1,3-dicarbo-substituted isochromene derivatives starting from 2-alkynyl(hetero)arylaldehydes and enolizable ketones. The reaction proceeds in a cascade fashion under mild heating with complete regioselectivity and moderate-to-good yields. In some cases, the reaction gives unexpected homodimeric products. Two competitive mechanistic paths for the formation of the desired isochromene derivatives and the homodimeric products are described.
- Dell'Acqua, Monica,Pirovano, Valentina,Peroni, Stefano,Tseberlidis, Giorgio,Nava, Donatella,Rossi, Elisabetta,Abbiati, Giorgio
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supporting information
p. 1425 - 1433
(2017/04/01)
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- Silver comes into play: Henry reaction and domino cycloisomerisation sequence catalysed by [Ag(i)(Pc-L)] complexes
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We report herein the synthesis of new pyridine-containing macrocyclic ligands (Pc-L) bearing a non-innocent pendant arm, by exploiting both chiral and functional properties of natural amino acids. The obtained macrocyclic ligands were employed to synthesize well-defined cationic silver(i) complexes that were shown to be competent catalysts for the Henry (nitroaldol) reaction. Good to excellent yields and full selectivity in the β-nitroalcohol product were obtained starting from electron-poor aromatic aldehydes or other activated aldehydes such as furfural under mild reaction conditions. The straightforward synthesis of the macrocyclic ligands starting from cheap commercially available starting materials allowed the introduction of a suitable basic functionality into the ligand pendant arm, thus providing a bifunctional catalyst. Based on our previous experience in the [Ag(i)(Pc-L)] catalysed domino addition/cycloisomerisation reaction of o-alkynylbenzaldehydes and nucleophiles, the synthesis of isochromenes coupling the Henry reaction and the cycloisomerisation in a single step was subsequently explored. Although with low selectivity, [Ag(i)(Pc-L)] cationic complexes were able to promote such a cascade reaction and a possible mechanism based on experimental evidence has been proposed.
- Tseberlidis, Giorgio,Dell'Acqua, Monica,Valcarenghi, Daniele,Gallo, Emma,Rossi, Elisabetta,Abbiati, Giorgio,Caselli, Alessandro
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p. 97404 - 97419
(2016/10/25)
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- A [2+2+2]-Cyclotrimerization Approach to Selectively Substituted Fluorenes and Fluorenols, and Their Conversion to 9,9′-Spirobifluorenes
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Synthesis of selectively substituted fluorenes and fluorenols was achieved by using catalytic [2+2+2]cyclotrimerization. Various starting diynes were reacted with different alkynes in the presence of a catalytic amount of Wilkinson's catalyst (RhCl(PPh3)3) providing the compounds possessing the fluorene scaffold in good isolated yields. A set of four regioselectively substituted fluorenols was converted to the corresponding 9,9′-spirobifluorenes and their spectral characteristics were measured. A select group! Selectively substituted fluorenes and fluorenols were synthesized by RhCl(PPh3)3 catalyzed [2+2+2]-cyclotrimerization of the diynes with alkynes. Fluorenols were subsequently transformed into a set of four regioselectively substituted 9,9′-spirobifluorenes.
- Kaiser, Reinhard P.,Hessler, Filip,Mosinger, Ji?í,Císa?ová, Ivana,Kotora, Martin
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supporting information
p. 13577 - 13582
(2015/09/22)
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- Copper Catalyzed Enantioselective Alkylation of Pyrrole with β,γ-Unsaturated α-Ketoesters: Application to One-Pot Construction of the Seven-Membered Ring by Merging a Gold Catalysis
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A highly enantioselective Friedel-Crafts alkylation of pyrrole to β,γ-unsaturated α-ketoesters was developed by virtue of a chiral copper complex, affording the alkylated derivatives of pyrrole with good yields and excellent enantioselectivities. Moreover, merging copper catalysis with gold catalysis realized a one-pot construction of the seven-membered ring to give annulated pyrroles with moderate to good yields and high enantiomeric excesses.
- Hu, Yanbin,Li, Yanan,Zhang, Sheng,Li, Chong,Li, Lijun,Zha, Zhenggen,Wang, Zhiyong
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supporting information
p. 4018 - 4021
(2015/09/01)
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- Silver-catalyzed domino hydroarylation/cycloisomerization reactions of ortho-alkynylbenzaldehydes: An entry to functionalized isochromene derivatives
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A Ag-catalyzed versatile and efficient access to 1H,1-arylisochromenes is reported. Starting from ortho-alkynylbenzaldehydes bearing various substitution patterns on the benzaldehyde and alkynyl units, the use of silver triflate (10 mol %) allowed a domino hydroarylation/cycloisomerization reaction process, leading to aryl-functionalized 1H-isochromene (>10 compounds, 80-98% yields). Notably, the reaction conditions were also compatible with benzaldehydes bearing an aliphatic-substituted alkynyl moiety with modest to good yields (34-88%, 10 compounds).
- Mariaule, Galle,Newsome, Gregory,Toullec, Patrick Y.,Belmont, Philippe,Michelet, Vronique
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supporting information
p. 4570 - 4573
(2015/02/19)
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- Mild regiospecific synthesis of 1-alkoxy-isochromenes catalyzed by well-defined [silver(I)(pyridine-containing ligand)] complexes
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The synthesis of 3-substituted-1-alkoxyisochromenes starting from 2-alkynylbenzaldehydes and different alcohols is reported. The reaction is catalyzed by a silver(I) complex with an original macrocyclic pyridine-containing ligand. The approach is characterized by absolute regioselectivity, mild reaction conditions, good to excellent reaction yields, cleanness of the reaction, and reduced purification steps. The reaction mechanism was investigated by in-depth 1H NMR experiments and an aimed trapping experiment.
- Dellacqua, Monica,Castano, Brunilde,Cecchini, Clara,Pedrazzini, Tommaso,Pirovano, Valentina,Rossi, Elisabetta,Caselli, Alessandro,Abbiati, Giorgio
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p. 3494 - 3505
(2014/05/06)
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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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- 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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- An efficient route to chiral N-heterocycles bearing a C-F stereogenic center via asymmetric hydrogenation of fluorinated isoquinolines
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An efficient iridium-catalyzed asymmetric hydrogenation of the fluorinated isoquinoline derivatives has been successfully developed for the synthesis of chiral fluorinated tetrahydroisoquinoline derivatives with up to 93% ee. This methodology features the use of a hydrochloride salt as well as a catalytic amount of halogenated hydantoin which were vital for the reactivity, enantioselectivity, and inhibition of the hydrodefluorination pathway. The Royal Society of Chemistry 2013.
- Guo, Ran-Ning,Cai, Xian-Feng,Shi, Lei,Ye, Zhi-Shi,Chen, Mu-Wang,Zhou, Yong-Gui
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supporting information
p. 8537 - 8539
(2013/09/23)
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- Highly regioselective synthesis of 1,3-diiodonaphthalene derivatives via a sequential cascade iodocyclization
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A novel and flexible sequentially cascade iodocyclization for the synthesis of highly substituted 1,3-diiodinated naphthalene derivatives in up to 99% yield under mild conditions is reported. The dihalogenated moiety can be readily introduced into the naphthalenes in a position that is usually not easily functionalized.
- Wang, Li-Jing,Zhu, Hai-Tao,Lu, Lei,Yang, Fang,Liu, Xue-Yuan,Liang, Yong-Min
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supporting information; experimental part
p. 1990 - 1993
(2012/06/01)
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- Gold-catalyzed oxidative cyclizations of 2-oxiranyl-1-alkynylbenzenes for diastereoselective synthesis of highly substituted 2-hydroxyindanones
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We report the gold-catalyzed oxidative cyclizations of 2-oxiranyl-1- alkynylbenzenes into highly substituted 2-hydroxyindanone frameworks bearing a tertiary alcohol. Such gold-catalyzed reactions comprise an initial internal redox reaction, sulfoxide oxidation of α-carbonyl gold-carbenoids, followed by gold-catalyzed formal ene reactions on the resulting diketone intermediates. Copyright
- Chaudhuri, Rupsha,Liu, Rai-Shung
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supporting information; experimental part
p. 2589 - 2592
(2011/12/01)
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- Concise synthesis of 1,2-dihydroisoquinolines and 1H-isochromenes by carbophilic lewis acid-catalyzed tandem nucleophilic addition and cyclization of 2-(1-alkynyl)arylaldimines and 2-(1-alkynyl)arylaldehydes
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(Chemical Equation Presented) By using carbophilic Lewis acids, In(OTf)3, NiCl2, and AuCl(PPh3)/AgNTf 2, a concise and efficient synthesis of 1,3-disubstituted 1,2-dihydroisoquinolines has been achieved via tandem nucleophilic addition and cyclization of 2-(1-alkynyl)arylaldimines. Addition of proton sources such as water, CF3CH2OH, and 2,6-di-tert-butyl-4-methoxyphenol was essential for the Lewis acid-catalyzed tandem reactions with organometallic reagents. By switching these catalysts, various types of nucleophiles such as allylstannanes, silyl enol ethers, alkenylboronic acids, and active methylene compounds could be introduced at the C1 position of 1,2-dihydroisoquinolines in this transformation. Furthermore, this method proved to be applicable to the synthesis of 1H-isochromene derivatives via the same tandem reaction of 2-(1-alkynyl)-arylaldehydes.
- Obika, Shingo,Kono, Hideki,Yasui, Yoshizumi,Yanada, Reiko,Takemoto, Yoshiji
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p. 4462 - 4468
(2008/02/05)
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- Synthesis of seven-membered-ring ketones by arylative ring expansion of alkyne-substituted cyclobutanones
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(Chemical Equation Presented) Ever-increasing circles: Seven-membered-ring ketones are constructed by a rhodium(I)-catalyzed arylative ring-expansion reaction of alkyne-substituted aryl cyclobutanones, in which two C-C bond-forming and one C-C bond-cleavi
- Matsuda, Takanori,Makino, Masaomi,Murakami, Masahiro
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p. 4608 - 4611
(2007/10/03)
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- PtBr2-catalyzed consecutive enyne metathesis-aromatization of 1-(1-methoxy-but-3-enyl)-2-(1-alkynyl)benzenes: Dual role of the Pt catalyst
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(Chemical Equation Presented) 1,7-Enynes 1, connected through an aromatic ring and bearing a leaving methoxy group at the 4-position, underwent the PtBr2-catalyzed enyne metathesis followed by aromatization in one pot to afford vinyl naphthalen
- Bajracharya, Gan B.,Nakamura, Itaru,Yamamoto, Yoshinori
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p. 892 - 897
(2007/10/03)
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- First partially intramolecular palladium-catalyzed [2+2+2] cycloaddition of benzyne: Application to the synthesis of benzo[b]fluorenones
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The palladium(O)-catalyzed reaction of benzyne with suitably functionalized benzodiynes to afford benzo[blfluorenones is described. The outcome of the reaction is affected by the steric and electronic properties of the diynes and proved to be regioselective when an unsymmetrically substituted aryne is used. This work represents the first example of a partially intramolecular [2+2+2] cycloaddition involving arynes. Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2003.
- Pena, Diego,Perez, Dolores,Guitian, Enrique,Castedo, Luis
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p. 1238 - 1243
(2007/10/03)
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