- Palladium-Catalyzed Alkene Thioacylation: A C?S Bond Activation Approach for Accessing Indanone Derivatives
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A palladium-catalyzed intramolecular alkene thioacylation reaction initiated by the activation of thioester C(acyl)?S bonds is reported. This approach successfully suppressed decarbonylation and β-hydrogen elimination with related acyl and alkyl metal thiolate intermediates, providing an efficient and atom-economical method to access indanone scaffolds. Mechanistic studies provide support for C(acyl)?Pd bond insertion of olefins. The synthetic utility of this protocol is demonstrated by the further conversion of the newly formed methylene sulfide substituent. (Figure presented.).
- Wu, Jianing,Xu, Wen-Hua,Lu, Hong,Xu, Peng-Fei
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supporting information
p. 3013 - 3017
(2021/05/07)
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- Carboxylation of Aryl Triflates with CO2 Merging Palladium and Visible-Light-Photoredox Catalysts
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We report herein a visible-light-promoted, highly practical carboxylation of readily accessible aryl triflates at ambient temperature and a balloon pressure of CO2 by the combined use of palladium and photoredox Ir(III) catalysts. Strikingly, the stoichiometric metallic reductant is replaced by a nonmetallic amine reductant providing an environmentally benign carboxylation process. In addition, one-pot synthesis of a carboxylic acid directly from phenol and modification of estrone and concise synthesis of pharmaceutical drugs adapalene and bexarotene have been accomplished via late-stage carboxylation reaction. Furthermore, a parallel decarboxylation-carboxylation reaction has been demonstrated in an H-type closed vessel that is an interesting concept for the strategic sector. Spectroscopic and spectroelectrochemical studies indicated electron transfer from the Ir(III)/DIPEA combination to generate aryl carboxylate and Pd(0) for catalytic turnover.
- Bhunia, Samir Kumar,Das, Pritha,Nandi, Shantanu,Jana, Ranjan
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supporting information
p. 4632 - 4637
(2019/06/27)
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- Visible light driven metal-free intramolecular cyclization: A facile synthesis of 3-position substituted 3,4-dihydroisoquinolin-1(2: H)-one
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A visible-light metal-free photocatalytic synthesis of 3-position substituted 3,4-dihydroisoquinolin-1(2H)-one derivatives under mild conditions in moderate to good yields is described. EosinY Na, an organic dye, which is of low cost and has good availability, is used as the photocatalyst. A wide range of substrates are tolerated and the gram-scale reaction can also proceed smoothly. Mechanistic studies indicate that a plausible free radical process is proposed.
- Zou, Shuai,Geng, Shu,Chen, Lina,Wang, Haitao,Huang, Feng
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supporting information
p. 380 - 387
(2019/01/10)
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- Catalytic C-N and C-H Bond Activation: Ortho-Allylation of Benzoic Acids with Allyl Amines
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A facile insertion of ruthenium into aromatic C-H and allylic C-N bonds are the key steps in a [Ru(p-cymene)Cl2]2-catalyzed ortho-C-H allylation of benzoic acids. This protocol allows drawing on the large pool of allylic amines for state-of-the-art ortho-functionalizations of arenes, turning neutral amines into leaving groups. Concise syntheses of biologically active compounds provide further evidence of the synthetic potential of this methodology.
- Hu, Xiao-Qiang,Hu, Zhiyong,Zhang, Guodong,Sivendran, Nardana,Goo?en, Lukas J.
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supporting information
p. 4337 - 4340
(2018/07/29)
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- Cyclic Hypervalent Iodine Reagents for Azidation: Safer Reagents and Photoredox-Catalyzed Ring Expansion
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Azides are building blocks of increasing importance in synthetic chemistry, chemical biology, and materials science. Azidobenziodoxolone (ABX, Zhdankin reagent) is a valuable azide source, but its safety profile has not been thoroughly established. Herein, we report a safety study of ABX, which shows its hazardous nature. We introduce two derivatives, tBu-ABX and ABZ (azidobenziodazolone), with a better safety profile, and use them in established photoredox- and metal-mediated azidations, and in a new ring-expansion of silylated cyclobutanols to give azidated cyclopentanones.
- Alazet, Sebastien,Preindl, Johannes,Simonet-Davin, Raphael,Nicolai, Stefano,Nanchen, Annik,Meyer, Thierry,Waser, Jerome
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p. 12334 - 12356
(2018/09/27)
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- Catalytic Isohypsic-Redox Sequences for the Rapid Generation of Csp3-Containing Heterocycles
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Cross-coupling reactions catalyzed by transition metals are among the most influential in modern synthetic chemistry. The vast majority of transition-metal-catalyzed cross-couplings rely on a catalytic cycle involving alternating oxidation and reduction o
- Smith, Craig D.,Phillips, David,Tirla, Alina,France, David J.
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p. 17201 - 17204
(2018/11/10)
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- Divergent Access to (1,1) and (1,2)-Azidolactones from Alkenes using Hypervalent Iodine Reagents
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A versatile synthesis of azidolactones through azidation and cyclization of carboxylic acids onto alkenes has been developed. Based on either photoredox or palladium catalysis, (1,1) and (1,2) azido lactones can be selectively synthesized. The choice of catalyst and benziodoxol(on)e reagent serving as azide source was essential to initiate either a radical or Lewis acid mediated process with divergent outcome. These transformations were carried out under mild conditions using a low catalyst loading and gave access to a large scope of azido lactones.
- Alazet, Sébastien,Le Vaillant, Franck,Nicolai, Stefano,Courant, Thibaut,Waser, Jerome
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supporting information
p. 9501 - 9504
(2017/07/22)
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- Intramolecular Hydroamidation of ortho-Vinyl Benzamides Promoted by Potassium tert-Butoxide/N,N-Dimethylformamide
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An intramolecular hydroamidation of ortho-vinyl benzamides had been developed. The reaction was promoted efficiently by potassium tert-butoxide and N,N-dimethylformamide without the need for strong oxidants or transition-metal catalysts. A series of dihyd
- Chen, Zhen-Yu,Wu, Liang-Yu,Fang, Hai-Sheng,Zhang, Ting,Mao, Zhi-Feng,Zou, Yong,Zhang, Xue-Jing,Yan, Ming
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p. 3894 - 3899
(2017/10/07)
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- Direct oxidative lactonization of alkenoic acids mediated solely by NaIO4: Beyond a simple oxidant
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Triflic acid-catalyzed direct oxidative lactonization of alkenoic acids mediated solely by NaIO4 without halogen salts is described. Sodium periodate works not only as an oxidant, but also as an active reagent and directly mediates the lactonization. A new cheap, green, and practical oxidative lactonization approach has been developed using NaIO4 as the sole reagent.
- Kang, Yan-Biao,Chen, Xian-Min,Yao, Chuan-Zhi,Ning, Xiao-Shan
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supporting information
p. 6193 - 6196
(2016/05/19)
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- Direct carbocyclizations of benzoic acids: Catalyst-controlled synthesis of cyclic ketones and the development of tandem aHH (acyl Heck-Heck) reactions
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The formation of exo-methylene indanones and indenones from simple ortho-allyl benzoic acid derivatives has been developed. Selective formation of the indanone or indenone products in these reactions is controlled by choice of ancillary ligand. This new process has a low environmental footprint as the products are formed in high yields using low catalyst loadings, while the only stoichiometric chemical waste generated from the reactants in the transformation is acetic acid. The conversion of the active cyclization catalyst into the Hermman-Beller palladacycle was exploited in a one-pot tandem acyl Heck-Heck (aHH) reaction, and utilized in the synthesis of donepezil. Carboxylic acids in aHH: Simple ortho-allyl benzoic acid derivatives have been utilized in an acyl Heck (aH) reaction to selectively form indanones and indenones. The conversion of the active cyclization catalyst into the Hermman-Beller palladacycle was exploited in a one-pot tandem acyl Heck-Heck (aHH) reaction to form two sp 2-sp2 bonds of (E)-trisubstituted olefins.
- Miles, Kelsey C.,Le, Chi,Stambuli, James P.
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supporting information
p. 11336 - 11339
(2014/10/16)
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- Beyond classical reactivity patterns: Hydroformylation of vinyl and allyl arenes to valuable β- And γ-aldehyde intermediates using supramolecular catalysis
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In this study, we report on properties of a series of rhodium complexes of bisphosphine and bisphosphite L1-L7 ligands, which are equipped with an integral anion binding site (the DIM pocket), and their application in the regioselective hydroformylation of vinyl and allyl arenes bearing an anionic group. In principle, the binding site of the ligand is used to preorganize a substrate molecule through noncovalent interactions with its anionic group to promote otherwise unfavorable reaction pathways. We demonstrate that this strategy allows for unprecedented reversal of selectivity to form otherwise disfavored β-aldehyde products in the hydroformylation of vinyl 2- and 3-carboxyarenes, with chemo- and regioselectivity up to 100%. The catalyst has a wide substrate scope, including the most challenging substrates with internal double bonds. Coordination studies of the catalysts under catalytically relevant conditions reveal the formation of the hydridobiscarbonyl rhodium complexes [Rh(Ln)(CO)2H]. The titration studies confirm that the rhodium complexes can bind anionic species in the DIM binding site of the ligand. Furthermore, kinetic studies and in situ spectroscopic investigations for the most active catalyst give insight into the operational mode of the system, and reveal that the catalytically active species are involved in complex equilibria with unusual dormant (reversibly inactivated) species. In principle, this involves the competitive inhibition of the recognition center by product binding, as well as the inhibition of the metal center via reversible coordination of either a substrate or a product molecule. Despite the inhibition effects, the substrate preorganization gives rise to very high activities and efficiencies (TON > 18‰000 and TOF > 6000 mol mol-1 h-1), which are adequate for commercial applications.
- Dydio, Pawe?,Detz, Remko J.,De Bruin, Bas,Reek, Joost N. H.
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p. 8418 - 8429
(2014/06/24)
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- Rhenium-catalyzed allylation of C-H bonds of benzoic and acrylic acids
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We have succeeded in the allylation of aromatic and olefinic C-H bonds of benzoic and acrylic acids using a rhenium catalyst, Re2(CO) 10. In this reaction, isomerization of the introduced allyl group to the 1-propenyl group did not occur.
- Kuninobu, Yoichiro,Ohta, Kazuhiro,Takai, Kazuhiko
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supporting information; experimental part
p. 10791 - 10793
(2011/11/05)
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- A palladium-catalyzed aminoalkynylation strategy towards bicyclic heterocycles: Synthesis of (±)-trachelanthamidine
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Sweet cyclizations: The synthesis of pyrrolizidines and indolizidines has been achieved. Olefins were subjected to an intramolecular palladium-catalyzed aminoalkynylation with the hypervalent iodine reagent TIPS-EBX. After removal of the protecting group, a two-step cyclization sequence and subsequent reduction led to the natural product (±)-trachelanthamidine (see scheme; TIPS-EBX=triisopropylsilyl ethynylbenziodoxolone).
- Nicolai, Stefano,Piemontesi, Cyril,Waser, Jerome
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p. 4680 - 4683
(2011/06/23)
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- Synthesis of C2-C3′N-linked macrocyclic taxoids. Novel docetaxel analogues with high tubulin activity
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Novel C2-C3′N-linked macrocyclic taxoids 4 bearing an aromatic ring at position C2 were synthesized. These compounds, tethered between N3′ and the C2-aromatic ring at the ortho, meta, or para position, were constructed by ring-closing metathesis. The para
- Querolle, Olivier,Dubois, Jo?lle,Thoret, Sylviane,Roussi, Fanny,Guéritte, Fran?oise,Guénard, Daniel
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p. 5937 - 5944
(2007/10/03)
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- Cyclization of aryl acyl radicals generated from S-(4-cyano)phenyl thiolesters by a nickel complex catalyzed electroreduction
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Aromatic acyl radicals generated from S-(4-cyano)phenyl 2-alkenylthiobenzoate by a nickel complex catalyzed electroreduction undergo 5- and 6-exo cyclization to give 1-indanone and dihydro-1-naphthalenone derivatives, respectively.
- Ozaki, Shigeko,Adachi, Masashi,Sekiya, Sayaka,Kamikawa, Rie
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p. 4586 - 4589
(2007/10/03)
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- Dialkylhydrazides for directed orthometalations
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Dimethylhydrazides are shown to be excellent substrates for the directed orthometalation reaction. The advantage of using the hydrazide is that it is easily removed by treatment with H5IO6 or CuCl2 to give the carboxylic acid under very mild conditions, in contrast to other amides that generally require harshly acidic conditions to achieve hydrolysis. (C) 2000 Elsevier Science Ltd.
- Pratt, Scott A.,Goble, Michael P.,Mulvaney, Michael J.,Wuts, Peter G. M.
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p. 3559 - 3562
(2007/10/03)
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- Synthesis of 3-alkyl-8-substituted- and 4-hydroxy-8-substituted-2,3,4,5-tetrahydro-1H-2-benzazepines
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Based on the Schimdt reaction and an iodolactone ring expansion reaction, two different synthetic routes to substituted 2,3,4,5-tetrahydro-1H-2-benzazepines were developed. The Schmidt reaction on 2,3-dihydro-2H-1-naphthalenone (1) gave 3, the product resulting from the alkyl group migration, as the major product instead of the tetrazole 2. This prompted the investigation of the Schmidt reaction on aromatic ketones 8 and 12. The product 9 due to alkyl group migration was the major product of the Schmidt reaction on 2-methyl-3,4-dihydro-2H-1-naphthalenone (8). The β-keto diester 12 gave a mixture of decarboxylated lactams after the Schmidt reaction. In this case, the lactam 13 resulting from the migration of the aromatic ring dominated over the other lactam 14. When lactam 14 was subjected to nitration, a single regioisomer was produced and transformed to the bromo alcohol 19. The other approach was based on the single pot ring expansion of the iodolactone 22 to the lactam 23 in the presence of methanolic ammonia. The iodolactone 22 was readily prepared from 2-allylbenzoic acid.
- Grunewald,Dahanukar
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p. 1609 - 1617
(2007/10/02)
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