- Pd-Catalyzed Heck-Type Reaction: Synthesizing Highly Diastereoselective and Multiple Aryl-Substituted P-Ligands
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In this work, an efficient palladium-catalyzed Heck-type reaction was successfully used to synthesize a wide range of monoaryl-or diaryl-substituted P-ligands with excellent yields and diastereoselectivity (up to 98% yield, dr >20:1). The preliminary mechanistic studies demonstrated that it possibly underwent a cationic Heck reaction that was assisted by silver salt, and it revealed the significant role of P(O)Ar2 for excellent yields and diastereoselectivity.
- Li, Chong,Qiang, Xiao-Yue,Qi, Zhi-Chao,Cao, Bin,Li, Jing-Yu,Yang, Shang-Dong
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- CRYSTAL FORMS AND METHODS OF SYNTHESIS OF (2R, 6R)-HYDROXYNORKETAMINE AND (2S, 6S)-HYDROXYNORKETAMINE
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The disclosure provides a method for synthesizing free base forms of (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-hydroxynorketamine. In an embodiment synthesis of (2R,6R)-hydroxynorketamine (HNK) includes preparation of (R)-norketamine via chiral resolution from racemic norketamine via a chiral resolution with L-pyroglutamic acid. The disclosure also provided crystal forms of the corresponding (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-hydroxynorketamine hydrochloride salts.
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Paragraph 0258; 0259; 0260
(2019/02/19)
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- Umpolung-like Cross-coupling of Tosylhydrazones with 4-Hydroxy-2-pyridones under Palladium Catalysis
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Tosylhydrazones under palladium catalysis were found to perform cross-coupling reactions with 4-hydroxy-2-pyridones. The umpolung-like reactivity, between the α-carbon of tosylhydrazone and the 3-position of the heterocycle, which is observed in the obtai
- Katsina, Tania,Papoulidou, Kyriaki Eleni,Zografos, Alexandros L.
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supporting information
p. 8110 - 8115
(2019/10/11)
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- Palladium-Catalyzed Cross-Coupling of gem-Bis(boronates) with Aryl Halides: An Alternative to Access Quaternary α-Aryl Aldehydes
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The compounds with a quaternary α-aryl aldehyde skeleton are important units in organic chemistry. Previously, the aryl group and carbonyl group are introduced in a stepwise manner. Herein, a novel route is developed to construct the quaternary α-aryl aldehydes with gem-bis(boronates) as precursors, in which the two groups are installed simultaneously. The gem-bis(boronates) are readily available from ketones; as a result, this methodology provides a more general strategy to produce the quaternary α-aryl aldehydes with broad scopes and synthetic convenience.
- Zheng, Purui,Zhai, Yujie,Zhao, Xiaoming,Xu, Tao
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supporting information
p. 393 - 396
(2019/01/23)
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- Zinc-promoted cyclization of tosylhydrazones and 2-(dimethylamino)malononitrile: An efficient strategy for the synthesis of substituted 1-tosyl-1: H -pyrazoles
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A Zn(OTf)2-promoted cyclization reaction of tosylhydrazones with 2-(dimethylamino)malononitrile has been successfully developed providing an efficient strategy for the synthesis of substituted 1-tosyl-1H-pyrazoles.
- Zhang, Bang-Hong,Lei, Lin-Sheng,Liu, Si-Zhan,Mou, Xue-Qing,Liu, Wei-Ting,Wang, Shao-Hua,Wang, Jie,Bao, Wen,Zhang, Kun
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supporting information
p. 8545 - 8548
(2017/08/04)
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- One-Pot Synthesis of Spirocyclic or Fused Pyrazoles from Cyclic Ketones: Calcium Carbide as the Carbon Source in Ring Expansion
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N-Tosylhydrazones generated in situ from cyclic ketones smoothly underwent a [3 + 2] cycloaddition to afford saturated spirocyclic pyrazoles and further transformed to the fused analogues via a ring expansion in certain cases. An inexpensive and renewable
- Yu, Yue,Chen, Yang,Huang, Wei,Wu, Wanqing,Jiang, Huanfeng
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p. 9479 - 9486
(2017/09/23)
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- Catalyst-free synthesis of spiropyrazolines from chalcones and cyclic ketone N -tosylhydrazones
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Treatment of cyclic ketone N-tosylhydrazones with chalcones in the presence of cesium carbonate at 110 °C affords spiropyrazolines with high selectivity and excellent yields. This protocol possesses many advantages such as readily available and stable sta
- Wu, Qin-Xi,Li, Hui-Jing,Wang, Hong-Shuang,Zhang, Zhen-Guo,Wang, Chen-Chao,Wu, Yan-Chao
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supporting information
p. 243 - 249
(2015/03/05)
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- Preparation of unsymmetrical ketones from tosylhydrazones and aromatic aldehydes via formyl C-H bond insertion
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Preparation of ketones by insertion of diazo compounds into the formyl C-H bond of an aldehyde is an attractive procedure, but use of structurally diverse diazo compounds is hampered by preparation and safety issues. A convenient procedure for the synthesis of unsymmetrical ketones from bench-stable tosylhydrazones and aryl aldehydes is reported. The procedure can be performed in one pot from the parent carbonyl compound and needs only a base, with no additional promoters being required.
- Allwood, Daniel M.,Blakemore, David C.,Ley, Steven V.
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supporting information
p. 3064 - 3067
(2014/06/23)
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- Catalytic enantioselective allylboration of propargylic aldehydes
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Homoallylic propargylic alcohols are important building blocks in natural product synthesis. This moiety can be transformed into various other structures by performing other known transformations, which can in turn lead to the synthesis of biologically us
- Bhakta, Urmibhusan,Sullivan, Erin,Hall, Dennis G.
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supporting information
p. 678 - 683
(2014/02/14)
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- Enantioselective aziridination of cyclic enals facilitated by the fluorine-iminium ion Gauche effect
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The enantioselective, organocatalytic aziridination of small, medium and macro-cyclic enals is reported using (S)-2-(fluorodiphenyl methyl)-pyrrolidine. Central to the reaction design is the reversible formation of a β-fluoroiminium ion intermediate, which is pre-organised on account of the fluorine-iminium ion gauche effect. This conformational effect positions the fluorine substituent synclinal-endo to the electropositive nitrogen centre thus benefiting from favourable stereoelectronic and electrostatic interactions (σC-H→σC-F*; F δ-···N+). Consequently, one of the shielding groups on the fluorine-bearing carbon atom is positioned above the π-system, forming the basis of an enantioinduction strategy. Treatment of this intermediate with a "nitrene" source furnished a series of novel, optically active aziridines (e.r. up to 99.5:0.5). Further derivatisation of the product aziridines gives facile access to various amino acid derivatives, including β-fluoroamino acids. Crystallographic analyses of both the aziridines and their derivatives are disclosed. Copyright
- Molnar, Istvan Gabor,Tanzer, Eva-Maria,Daniliuc, Constantin,Gilmour, Ryan
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supporting information
p. 794 - 800
(2014/01/23)
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- Formal carbon insertion of n-tosylhydrazone into B-B and B-Si bonds: Gem-diborylation and gem-silylborylation of sp3 carbon
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A convenient method is developed to synthesize 1,1-diboronates from the corresponding N-tosylhydrazones. This method is also applicable to synthesize 1-silyl-1-boron compounds. Meanwhile, derivatization and consecutive Pd-catalyzed cross-coupling reaction
- Li, Huan,Shangguan, Xianghang,Zhang, Zhikun,Huang, Shan,Zhang, Yan,Wang, Jianbo
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supporting information
p. 448 - 451
(2014/04/03)
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- Facile one-pot synthesis of N-alkylated benzimidazole and benzotriazole from carbonyl compounds
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An efficient one-pot N-alkylation of benzimidazole and benzotriazole from carbonyl compounds and tosylhydrazide has been accomplished via copper powder-catalyzed N - H bond insertion affording N-alkylated products in good yields. The reaction can tolerate a wide range of carbonyl compounds, such as aryl, alkyl, heterocyclic and α,β-unsaturated ketones, and aldehydes.
- Meng, Xu,Li, Xiaolong,Chen, Wenlin,Zhang, Yuanqing,Wang, Wen,Chen, Jinying,Song, Jinli,Feng, Huijie,Chen, Baohua
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p. 349 - 356
(2014/04/17)
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- The benzyne Fischer-indole reaction
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A new approach to the Fischer-indole synthesis is reported that uses the reactive intermediate benzyne. The addition of N-tosyl hydrazones to arynes, generated through fluoride activation of 2-(trimethylsilyl)phenyl triflate precursors, leads to efficient
- McAusland, Donald,Seo, Sangwon,Pintori, Didier G.,Finlayson, Jonathan,Greaney, Michael F.
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supporting information; experimental part
p. 3667 - 3669
(2011/09/16)
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- Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
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We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
- Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
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supporting information; experimental part
p. 8481 - 8490
(2009/02/02)
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- Convenient preparation of cycloalkenyl boronic acid pinacol esters
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A practical method for the preparation of cycloalkenyl boronic acid pinacol esters is described. These important synthetic intermediates are typically made using more expensive methods like transition metal-catalyzed borylation of alkenyl halides or trifl
- Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
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experimental part
p. 3984 - 3995
(2009/04/11)
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- Synthesis of new (3-aminopyrrolidin-3-yl)phosphonic acid - A cucurbitine analogue - and (3-aminotetrahydrothiophen-3-yl)phosphonic acid via phosphite addition to heterocyclic hydrazones
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Hydrazones were prepared by condensation of carbocyclic and heterocyclic ketones with benzoyl- and tosylhydrazines. These hydrazones underwent nucleophilic addition with phosphite to provide efficiently (3- hydrazinopyrrolidin-3-yl)-, (3-hydrazinotetrahydrothiophen-3-yl)-, (3-hydrazinotetrahydrofuran-3-yl)-, and (1-hydrazinocyclopentyl)phosphonates. Cleavage of the hydrazine N-N bonds followed by acidic hydrolysis of the phosphonate functions of the (3-aminoheterocyclopentyl)phosphonates gave the new (3-aminopyrrolidin-3-yl)- and (3-aminotetrahydrothiophen-3-yl)phosphonic acids. This synthesis was achieved in a four-step sequence from the appropriate ketones. Georg Thieme Verlag Stuttgart.
- Rabasso, Nicolas,Fadel, Antoine
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experimental part
p. 2353 - 2362
(2009/04/05)
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- Generation and Solution-phase Behaviour of Some 2-Halogeno-1,3-ring-fused Cyclopropenes
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The title cyclopropenes 2b are readily formed by reaction of ring-fused β-silylated-gem-dihalogenocyclopropanes of the general type 1b with tetrabutylammonium fluoride in tetrahydrofuran solution.Those halogenocyclopropenes 2b which are fused to a seven-
- Banwell, Martin G.,Corbett, Madelaine,Gulbis, Jacqueline,Mackay, Maureen F.,Reum, Monica E.
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p. 945 - 964
(2007/10/02)
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- Reaction of Substituted Hydrazones with Thionyl Chloride and Sulfuryl Chloride
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Treatment of acetylhydrazones 2, ethoxycarbonylhydrazones 3, p-tolylsulfonylhydrazones 4 or semicarbazones 5 with thionyl chloride leads to the 1,2,3-thiadiazoles 6a-o.Sulfuryl chloride on the other hand accomplishes the transfer of chlorine without incorporating a sulfur atom.The new synthesized 1,2,3-thiadiazoles 6g-o are characterized in detail by spectroscopic methods.
- Meier, Herbert,Trickes, Georg,Laping, Elisabeth,Merkle, Ursula
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p. 183 - 192
(2007/10/02)
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