- Hydroacenes Made Easy by Gold(I) Catalysis
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A novel strategy for the synthesis of partially saturated acene derivatives has been developed based on a AuI-catalyzed cyclization of 1,7-enynes. This method provides straightforward access to stable polycyclic products featuring the backbone of the acene series, up to nonacene.
- Dorel, Ruth,McGonigal, Paul R.,Echavarren, Antonio M.
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- The Hancock Alkaloids (-)-Cuspareine, (-)-Galipinine, (-)-Galipeine, and (-)-Angustureine: Asymmetric Syntheses and Corrected 1H and 13C NMR Data
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The asymmetric syntheses of all members of the Hancock alkaloid family based upon a 2-substituted N-methyl-1,2,3,4-tetrahydroquinoline core are delineated. The conjugate addition of enantiopure lithium N-benzyl-N-(α-methyl-p-methoxybenzyl)amide to 5-(o-br
- Davies, Stephen G.,Fletcher, Ai M.,Houlsby, Ian T. T.,Roberts, Paul M.,Thomson, James E.,Zimmer, David
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Read Online
- Enantioselective Palladium-Catalyzed Intramolecular α-Arylative Desymmetrization of 1,3-Diketones
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An efficient enantioselective protocol has been reported to build highly oxygenated and densely substituted bicyclo[m.n.1] skeletons through intramolecular asymmetric α-arylative desymmetrization of 1,3-diketones. Employing Pd catalyst and FOXAP ligand, various bicyclo[m.n.1] skeleton with different size can be accessed with high enantio- and diastereoselectivities. Utilizing the present method as a key step, formal asymmetric total synthesis of the (-)-parvifoline has been demonstrated.
- Zhu, Chendan,Wang, Dingyi,Zhao, Yue,Sun, Wei-Yin,Shi, Zhuangzhi
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Read Online
- Enantioselective Iridium-Catalyzed Allylation of Nitroalkanes: Entry to β-Stereogenic α-Quaternary Primary Amines
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The first systematic study of simple nitronate nucleophiles in iridium-catalyzed allylic alkylation is described. Using a tol-BINAP-modified π-allyliridiumC,O-benzoate catalyst, α,α-disubstituted nitronates substitute racemic branched alkyl-substituted al
- Jung, Woo-Ok,Mai, Binh Khanh,Spinello, Brian J.,Dubey, Zachary J.,Kim, Seung Wook,Stivala, Craig E.,Zbieg, Jason R.,Liu, Peng,Krische, Michael J.
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supporting information
p. 9343 - 9349
(2021/07/19)
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- Access to Trisubstituted Fluoroalkenes by Ruthenium-Catalyzed Cross-Metathesis
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Although the olefin metathesis reaction is a well-known and powerful strategy to get alkenes, this reaction remained highly challenging with fluororalkenes, especially the Cross-Metathesis (CM) process. Our thought was to find an easy accessible, convenient, reactive and post-functionalizable source of fluoroalkene, that we found as the methyl 2-fluoroacrylate. We reported herein the efficient ruthenium-catalyzed CM reaction of various terminal and internal alkenes with methyl 2-fluoroacrylate giving access, for the first time, to trisubstituted fluoroalkenes stereoselectively. Unprecedent TON for CM involving fluoroalkene, up to 175, have been obtained and the reaction proved to be tolerant and effective with a large range of olefin partners giving fair to high yields in metathesis products. (Figure presented.).
- Nouaille, Augustin,Pannecoucke, Xavier,Poisson, Thomas,Couve-Bonnaire, Samuel
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supporting information
p. 2140 - 2147
(2021/03/06)
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- Synthesis of rac-ɑ-aryl propionaldehydes via branched-selective hydroformylation of terminal arylalkenes using water-soluble Rh-PNP catalyst
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This work detailed the preparation of a class of water-soluble PNP ligands that differed by the nature of the substitute on phenyl ring of ligands. These ligands were incorporated into water-soluble rhodium-PNP complex catalysts that were used to regioselective hydroformylation of a series of terminal arylalkenes, providing efficient access to rac-α-aryl propionaldehydes in good to excellent yield (up to 97%) and branched-regioselectivity (up to 40:1 b/l ratio). Furthermore, gram-scale and diverse synthetic transformation demonstrated synthetic application of this methodology for non-steroidal antiinflammatory drugs.
- Chen, Fen-Er,Gao, Peng,Ke, Miaolin,Liang, Guanfeng,Ru, Tong
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- Remote Functionalization of α,β-Unsaturated Carbonyls by Multimetallic Sequential Catalysis
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The remote functionalization of α,β-unsaturated carbonyls by an array of multimetallic sequential catalytic systems is described. The reactions are triggered by hydrometalation using [Pd-H] or [Ru-H] isomerization catalysts and driven by the formation of thermodynamically more stable 1,2-vinyl arenes. The Pd-catalyzed deconjugative isomerization was combined with a Cu-catalyzed β-borylation of the transiently generated styrenyl derivatives to deliver a range of products that would not be accessible with the use of a single catalyst. [Pd/Cu] catalytic systems were also identified for the highly enantioselective α-hydroboration and α-hydroamination of the styrenyl intermediates. Difunctionalization simultaneously at the benzylic and homobenzylic positions was achieved by combining the isomerization process with Sharpless asymmetric dihydroxylation (SAD) using [Pd/Os] or [Ru/Os] couples. Starting from a simple α,β-unsaturated ester, an isomerization/dihydroxylation/lactonization sequence gave access to a naturally occurring γ-butyrolactone in good yield, with excellent diastereo- and enantioselectivity.
- Romano, Ciro,Fiorito, Daniele,Mazet, Clément
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supporting information
p. 16983 - 16990
(2019/10/28)
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- Carbene-Catalyzed α-Carbon Amination of Chloroaldehydes for Enantioselective Access to Dihydroquinoxaline Derivatives
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An NHC-catalyzed α-carbon amination of chloroaldehydes was developed. Cyclohexadiene-1,2-diimines are used as amination reagents and four-atom synthons. Our reaction affords optically enriched dihydroquinoxalines that are core structures in natural products and synthetic bioactive molecules.
- Huang, Ruoyan,Chen, Xingkuan,Mou, Chengli,Luo, Guoyong,Li, Yongjia,Li, Xiangyang,Xue, Wei,Jin, Zhichao,Chi, Yonggui Robin
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supporting information
p. 4340 - 4344
(2019/06/14)
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- Direct Access to N-tert-Butanesulfinyl Imines from Aryl Iodides, Alkenyl Alcohols, and N-tert-Butanesulfinamide
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The reaction of aryl iodides, N-tert-butanesulfinamide, and allyl or homoallyl alcohol in the presence of a catalytic amount of Pd(OAc)2, NaHCO3 as a base, and TBAB leads to the formation of N-tert-butanesulfinyl imines in moderate yields. In this one-pot process, a sequential Heck-type arylation of the alkenol, isomerization of the double bond, and imine formation take place.
- Ikhlef, Sofiane,Behloul, Cherif,Lahosa, Alejandro,Foubelo, Francisco,Yus, Miguel
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p. 2609 - 2614
(2018/05/03)
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- FUNCTIONALIZED MAGNETIC NANOPARTICLE, A CATALYST, A METHOD FOR FORMING C-C BONDS
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A functionalized magnetic nanoparticle including an organometallic sandwich compound and a magnetic metal oxide. The functionalized magnetic nanoparticle may be reacted with a metal precursor to form a catalyst for various C—C bond forming reactions. The catalyst may be recovered with ease by attracting the catalyst with a magnet.
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Paragraph 0210
(2018/04/20)
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- Chemo- and Regioselective Organo-Photoredox Catalyzed Hydroformylation of Styrenes via a Radical Pathway
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An unprecedented, chemo- and regioselective, organo-photoredox catalyzed hydroformylation reaction of aryl olefins with diethoxyacetic acid as the formylation reagent is described. In contrast to traditional transition metal promoted ionic hydroformylation reactions, the new process follows a unique photoredox promoted, free radical pathway. In this process, a formyl radical equivalent, produced from diethoxacetic acid through a dye (4CzIPN) photocatalyzed, sequential oxidation-decarboxylation route, regio- and chemoselectively adds to a styrene substrate. Importantly, under the optimized reaction conditions the benzylic radical formed in this manner is reduced by SET from the anion radical of 4CzIPN to generate a benzylic anion. Finally, protonation produces the hydroformylation product. By using the new protocol, aldehydes can be generated regioselectively in up to 90% yield. A broad array of functional groups is tolerated in the process, which takes place under mild, metal-free conditions.
- Huang, He,Yu, Chenguang,Zhang, Yueteng,Zhang, Yongqiang,Mariano, Patrick S.,Wang, Wei
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supporting information
p. 9799 - 9802
(2017/08/02)
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- Intra- and Intermolecular Nickel-Catalyzed Reductive Cross-Electrophile Coupling Reactions of Benzylic Esters with Aryl Halides
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Nickel-catalyzed cross-electrophile coupling reactions of benzylic esters and aryl halides have been developed. Both inter- and intramolecular variants proceed under mild reaction conditions. A range of heterocycles and functional groups are tolerated under the reaction conditions. Additionally, the first example of a stereospecific cross-electrophile coupling of a secondary benzylic ester is described. Crossed off: Nickel-catalyzed cross-electrophile coupling reactions of benzylic esters and aryl halides have been developed. Both inter- and intramolecular variants proceed under mild reaction conditions, and a range of heterocycles and functional groups are tolerated. Additionally, the first example of a stereospecific cross-electrophile coupling of a secondary benzylic ester is described.
- Konev, Mikhail O.,Hanna, Luke E.,Jarvo, Elizabeth R.
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supporting information
p. 6730 - 6733
(2016/06/09)
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- Enantioselective hydroformylation of 2- and 4-substituted styrenes with PtCl2[(R)-BINAP] + SnCl2‘in situ’ catalyst
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Two sets of styrenes possessing various substituents either in ortho or para position were hydroformylated in the presence of ‘in situ’ catalyst formed from PtCl2[(R)-BINAP] and tin(II) chloride. The reversal of the absolute configuration of the preferred enantiomers was observed using both sets of substrates by the variation of the reaction temperature in the range of 40–100 °C. In case of the 4-substituted styrenes, the reversal temperature of the enantioselectivity shows correlation with the Hammett substituent constants, i.e., with the electron donor or electron acceptor properties of the para-substituents. This phenomenon was explained by the reversible formation of the Pt-branched alkyl intermediates, leading to the corresponding (R)- and (S)-enantiomers of 2-arylpropanals. Strong substituent effect on the regioselectivity was observed in the hydroformylation of 2-substituted styrenes: the presence of substituents characterised by larger steric parameter resulted in the highly favoured formation of the linear aldehyde. For instance, regioselectivities of 45%, 22% and 7% towards branched aldehyde were obtained with styrene, 2-fluoro- and 2-bromostyrene, respectively, at 80 °C reaction temperature. In addition to the characteristic change of regioselectivity, the reversal of absolute configuration as a function of reaction temperature was also observed.
- Pongrácz, Péter,Kollár, László
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p. 118 - 123
(2016/10/25)
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- Asymmetric synthesis of 3-substituted tetrahydro-2-benzazepines
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The enantiomerically and diastereomerically pure tricyclic oxazolidine cis-10 was prepared in a five step synthesis starting with 1-bromo-2-iodobenzene. Me3SiCN and allylSiMe3 reacted with cis-10 in the presence of TiCl4 to form the nitrile (3S)-11 and the allyl derivative (3S)-12 with high diastereoselectivity. The hydrogenolytic removal of the chiral auxiliary failed, since the endocyclic benzyl-N-bond was cleaved simultaneously. Therefore the N-(hydroxyethyl)amide of (3S)-12 was transformed into the enamide 27, which was hydrolyzed to afford the secondary amide 28. The enamide strategy to remove the chiral auxiliary from (3S)-11 led to complete racemization due to fast deprotonation in α-position of the cyano moiety. Two pairs of enantiomers 30a-b/ent-30a-b with prototypical σ substituents at the N-atom were prepared. The low σ1 affinity of the tetrahydro-2-benzazepines (ent-30b, Ki = 407 nM) is attributed to the short distance between the two lipophilic aromatic moieties.
- Quick, Matthias P.,Fr?hlich, Roland,Schepmann, Dirk,Wünsch, Bernhard
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p. 7265 - 7281
(2015/07/01)
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- Enantioselective carbocycle formation through intramolecular Pd-catalyzed allyl-aryl cross-coupling
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Aryl electrophiles containing tethered allylboronate units undergo efficient intramolecular coupling in the presence of a chiral palladium catalyst to give enantioenriched carbocyclic products. The reaction is found to be quite general, affording 5, 6, an
- Schuster, Christopher H.,Coombs, John R.,Kasun, Zachary A.,Morken, James P.
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supporting information
p. 4420 - 4423
(2015/01/09)
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- Bimolecular coupling reactions through oxidatively generated aromatic cations: Scope and stereocontrol
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Chromenes, isochromenes, and benzoxathioles react with 2,3-dichloro-5,6- dicyano-1,4-benzoquinone to form stable aromatic cations that react with a range of nucleophiles. These oxidative fragment coupling reactions provide rapid access to structurally div
- Cui, Yubo,Villafane, Louis A.,Clausen, Dane J.,Floreancig, Paul E.
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p. 7618 - 7626
(2013/08/23)
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- Highly diastereoselective radical cyclisations of chiral sulfinimines
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Chiral amines are formed by the highly diastereoselective intramolecular addition of alkyl and aryl radicals onto chiral mesityl sulfinimines.
- Rochette, Elise M.,Lewis, William,Dossetter, Al G.,Stockman, Robert A.
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supporting information
p. 9395 - 9397
(2013/10/01)
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- Gold-catalyzed diastereoselective [2+2+2]-cycloaddition of 1,7-enynes with carbonyl compounds
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We report a gold-catalyzed [2+2+2]-cycloaddition of 1,7-enynes with carbonyl species; our experimental data suggest that the resulting oxacyclic cycloadducts arose from an interception of gold-containing cyclobutenium intermediates with carbonyl species.
- Huple, Deepak B.,Liu, Rai-Shung
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supporting information
p. 10975 - 10977
(2013/01/15)
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- Synthesis of tetrasubstituted alkenes through a palladium-catalyzed domino carbopalladation/C-H-activation reaction
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Helical tetrasubstituted alkenes (7) were obtained in a highly efficient way through a palladium-catalyzed domino-carbopalladation/CH-activation reaction of propargylic alcohols 6 in good to excellent yields. Electron-withdrawing- and electron-donating substituents can be introduced onto the upper and lower aromatic rings. The substrates (6) for the domino process were synthesized by addition of the lithiated alkyne (20) to various aldehydes (19); moreover, the substrates were accessible enantioselectively (in 95 % ee) by reduction of the corresponding ketone using the Noyori procedure. Copyright
- Tietze, Lutz F.,Hungerland, Tim,Duefert, Alexander,Objartel, Ina,Stalke, Dietmar
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supporting information; experimental part
p. 3286 - 3291
(2012/04/17)
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- Manganese(III)-mediated phosphinoyl radical reactions for stereoselective synthesis of phosphinoylated tetrahydronaphthalenes
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Reactions of diphenylphosphinoyl radicals with 5-aryl-2-pentenoates or β-phenylethylene styrenes generate trans-substituted tetrahydronaphthalenes through a cascade reaction sequence.
- Pan, Xiang-Qiang,Wang, Lu,Zou, Jian-Ping,Zhang, Wei
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experimental part
p. 7875 - 7877
(2011/09/12)
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- (3R,11aR)-3-Phenyl-2,3,11,11a-tetrahydro-[1,3]oxazolo[3,2-b]-[2]benzazepin-5(10H)-one as a chiral building block for the asymmetric synthesis of 3-substituted 2-benzazepines
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A five-step synthesis of the chiral building block cis-2 is described. Key steps in the synthesis were a Heck reaction of 1-bromo-2-iodobenzene with allyl alcohol, the introduction of a carboxy group after Br/Li-exchange, and the diastereoselective format
- Quick, Matthias P.,Froehlich, Roland,Wuensch, Bernhard
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scheme or table
p. 524 - 526
(2010/07/20)
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- Unsymmetrical biaryls by palladium-catalyzed coupling of aryl halides with internal reduction
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Aryl bromides containing a (1,4,5,6-tetrahydro-6-oxopyridin-3-yl)methyl substituent can be coupled with aryl halides yielding unsummetrical biaryls. In the course of this process, the cyclic enamide is oxidized to the 2(1H)-pyridinone. The reaction procee
- Satyanarayana, Gedu,Maier, Martin E.
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scheme or table
p. 5543 - 5552
(2009/05/11)
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- Biaryl formation from 5-(2-bromobenzyl)-substituted piperidin-2-ones via palladacycles
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(Chemical Equation Presented) The reaction of piperdin-2-ones with a 2-bromobenzyl substituent in the 5-position in the presence of a palladium catalyst leads to biaryl compounds. Their formation can be explained via initial C-H insertion of the aryl pall
- Satyanarayana, Gedu,Maier, Martin E.
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scheme or table
p. 2361 - 2364
(2009/05/27)
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- Synthesis of 1,5-methano-3-benzazocines by intramolecular Buchwald-Hartwig arylation of 2-piperidinones
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A conceptually novel route to 1,5-methano-3-benzazocines based on an intramolecular Buchwald-Hartwig arylation was developed. The reaction required the use of the zinc enolate of the piperidinone substrates. These substrates, piperidin-2-ones with a 2-bro
- Satyanarayana, Gedu,Maier, Martin E.
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p. 356 - 363
(2008/04/01)
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- PROCESS FOR PREPARING A LEUKOTRIENE ANTAGONIST
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Process for preparing montelukast or a pharmaceutically acceptable salt thereof, especially its sodium salt, that comprises the condensation of an aldehyde and 7-chloro-2-methylquinoline. Moreover, novel intermediates useful for the synthesis of montelukast are described as well as their preparation.
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Page/Page column 16
(2008/06/13)
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- Intramolecular Pd-catalyzed carboetherification and carboamination. Influence of catalyst structure on reaction mechanism and product stereochemistry
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The intramolecular Pd-catalyzed carboetherification of alkenes affords 2-indan-1-yltetrahydrofuran products in moderate to good yield with good to excellent levels of diastereoselectivity. The stereochemical outcome of these reactions is dependent on the
- Nakhla, Josephine S.,Kampf, Jeff W.,Wolfe, John P.
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p. 2893 - 2901
(2007/10/03)
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- A study on the regio- and stereoselectivity in palladium-catalyzed cyclizations of alkenes and alkynes bearing bromoaryl and nucleophilic groups
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We have studied the remarkable dependence of the stereochemistry of the cyclization on the double bond geometry and of the effect of the bulkiness of the nucleophile on the regiochemistry of the palladium mediated cyclization of alkenes bearing aryl bromides and nucleophiles. In contrast, the cyclization of the acetylenic homologous substrates is not dependent on the nature of the nucleophile.
- Bruyère, Didier,Bouyssi, Didier,Balme, Geneviève
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p. 4007 - 4017
(2007/10/03)
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- An efficient synthesis of furyl sulfonamides from the reaction of furan with in situ generated N-tosyl imines
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Treatment of an aldehyde and furan with N-sulfinyl-p-toluenesulfonamide/zinc chloride leads to the formation of furyl sulfonamides via an in situ generated N-tosyl imine intermediate. In one case, a novel 4-tosylamino-5,6-dihydro-4H-3-oxa-benz[e]azulene w
- Padwa, Albert,Zanka, Atsuhiku,Cassidy, Michael P.,Harris, Joel M.
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p. 4939 - 4944
(2007/10/03)
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- Efficient synthesis of tetrasubstituted alkenes by allylsilane-terminated domino-Heck double cyclisation
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The domino-Heck double cyclisation of the arylbromides 1, which contain an allylsilane and an alkyne moiety and are easily accessible by an addition of the corresponding lithiated alkynes 5 to the aldehydes 4, leads to the tetrasubstituted alkenes 2 and 3
- Tietze, Lutz F.,Kahle, Klaus,Raschke, Thomas
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p. 401 - 407
(2007/10/03)
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- A bromoarene based approach to phenylalanine analogues Hic and Nic
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A Heck reaction system incorporating Ph4PCl and using bromoarenes as substrates has enabled the syntheses of the conformationally constrained phenylalanine analogues Hic and Nic to be dramatically shortened thus facilitating the production of significant quantities of these amino acids.
- Gibson, Susan E.,Jones, Jerome O.,McCague, Ray,Tozer, Matthew J.,Whitcombe, Nicole J.
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p. 954 - 956
(2007/10/03)
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- Cascade radical cyclisations with vinylcyclopropane electrophores
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Treatment of the polyene iodide 3, containing a vinylcyclopropane electrophore, with tris-(trimethylsilyl)silane (TTMSS)-AIBN gave 6 and 7 (2:1, 65%) resulting from a radical cascade 13-endo macrocyclisation followed by successive 6-exo/5-exo transannular cyclisations. In a similar manner, the iodo vinylcyclopropane 12a underwent triple cyclisation to a mixture of diastereoisomers of the oestrone analogue 14 (~ 16%), but the vinylcyclopropyl ester 9a gave only the product 11 of macrocyclisation on treatment with TTMSS-AIBN.
- Pattenden, Gerald,Wiedenau, Paul
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p. 3647 - 3650
(2007/10/03)
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- A steric control of regioselectivity in palladium-catalyzed cyclizations of alkenes bearing arylbromides and nucleophiles
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The stereocontrolled synthesis of tricyclic compounds through an efficient and highly regioselective 5-exo-trig palladium catalyzed biscyclization process is reported, starting from compounds 1. The 6-endo competing cyclization can also be the only pathwa
- Bruyere, Didier,Gaignard, Gaelle,Bouyssi, Didier,Balme, Genevieve,Lancelin, Jean-Marc
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p. 827 - 830
(2007/10/03)
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- Intramolecular palladium-catalyzed aryl amination and aryl amidation
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Upon treatment with a palladium catalyst and a suitable base, aromatic halides undergo intramolecular substitution to form five, six, and seven-membered rings. In a similar fashion aryl halides with pendant amides or sulfonamides are cyclized to form five and six-membered rings.
- Wolfe, John P.,Rennels, Roger A.,Buchwald, Stephen L.
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p. 7525 - 7546
(2007/10/03)
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- Lithium-Halogen Exchange-Initiated Cyclization Reactions. 3. Intramolecular Conjugate Addition Reactions of Unsaturated Acylphosphoranes
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The lithium-halogen exchange-initiated intramolecular conjugate addition reactions of some model unsaturated acylphosphoranes have been examined.The effects of halide type, chain length, and acceptor substitution pattern on the feasibility of ring construction were studied.The lithium-bromine exchange reactions in two 2-bromooaryl acceptors were found to be too slow, relative to competing side reactions, to allow practical carbocycle syntheses while 3-,4-,5-, and 6-membered carbocycles are formed in good to excellent yields from precursors that are vinyl and saturated primary iodides.Highly efficient intramolecular conjugate addition reactions to β,β-disubstituted acceptor units are possible, and intermediate anions from intramolecular conjugate addition reactions are readily captured with electrophiles.
- Cooke, Manning P.,Widener, Rexford K.
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p. 1382 - 1396
(2007/10/02)
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