- Desymmetrisation of meso difuryl alcohols, diols and their derivatives: Complementary directed and undirected asymmetric dihydroxylation reactions
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Asymmetric reactions (for example, asymmetric epoxidation and asymmetric dihydroxylation) were examined for the desymmetrisation of the meso substrates 1,1-difuran-2-ylmethanol,N-(1,1-difuran-2-ylmethyl)-4- methylbenzenesulfonamide, (R,S)-1,4-difuran-2-yl
- Hodgson, Robert,Majid, Tahir,Nelson, Adam
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- Manganese=Catalyzed Achmatowicz Rearrangement Using Green Oxidant H2O2
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Oxidation reactions have been extensively studied in the context of the transformations of biomass=derived furans. However, in contrast to the vast literature on utilizing the stoichiometric oxidants, such as m=CPBA and NBS, catalytic methods for the oxidative furan=recyclizations remain scarcely investigated. Given this, we report a means of manganese=catalyzed oxidations of furan with low loading, achieving the Achmatowicz rearrangement in the presence of hydrogen peroxide as an environmentally benign oxidant under mild conditions with wide functional group compatibility.
- Gao, Ziwei,Gou, Jing,Hao, Zhe,Hou, Jing,Li, Chaoqun,Li, Gaoqiang,Xing, Qingzhao,Yu, Binxun
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p. 9563 - 9586
(2021/07/20)
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- Chiral-Directing-Group-Assisted Rhodium(III)-Catalyzed Asymmetric Addition of Inert Arene C?H Bond to Aldimines with Subsequent Intramolecular Cyclization
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By using a chiral directing group, an asymmetric rhodium(III)-catalyzed C?H bond addition to aldimines followed by intramolecular cyclization to form chiral isoindolinones has been achieved (up to 68 % yield, up to 93 % ee). A three-component variant that resembles Mannich reaction was also realized (41 % yield, 83 % ee). Product elaborations and preliminary mechanistic studies were described.
- Cai, Xuhong,Chen, Wenkun,Nie, Ruifang,Wang, Jun
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supporting information
p. 16611 - 16615
(2021/10/19)
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- Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics
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Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving biologically important tetrahydro-β-carbolines via a Friedel-Crafts mechanism.
- Drew, Melanie A.,Arndt, Sebastian,Richardson, Christopher,Rudolph, Matthias,Hashmi, A. Stephen K.,Hyland, Christopher J. T.
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supporting information
p. 13971 - 13974
(2019/11/25)
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- Domino Synthesis of 3-Alkyliden-2,3-Dihydro-4-Quinolones
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The synthesis of 3-alkyliden-2,3-dihydro-4-quinolones has been accomplished in a domino fashion through a three-step sequence that comprised an initial aza-Baylis-Hillman reaction, followed by a 1,3-rearrangement and an intramolecular amination. Starting from readily available aryl vinyl ketones and N-tosyl imines, the reaction with PPh3, CsOAc and CuI in CH3CN gave rise, in good overall yields, to final 3-alkyliden-4-quinolone derivatives, valuable scaffolds in medicinal chemistry. The simultaneous addition of two bases, PPh3 and CsOAc, was found to be crucial for the success of the process. While PPh3 promoted the reversible aza-Baylis-Hillman reaction, CsOAc triggered the subsequent 1,3-rearrangement, which shifted the initial equilibrium and allowed to complete the synthetic sequence upon the addition of CuI. (Figure presented.).
- Raga, Esther,Escolano, Marcos,Torres, Javier,Rabasa-Alca?iz, Fernando,Sánchez-Roselló, María,del Pozo, Carlos
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supporting information
p. 1102 - 1107
(2019/01/30)
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- Synthesis of Benzyl Amines via Copper-Catalyzed Enantioselective Aza-Friedel-Crafts Addition of Phenols to N -Sulfonyl Aldimines
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A new copper-catalyzed enantioselective aza-Freidel-Crafts reaction between phenols and N-sulfonyl aldimines that provides chiral secondary benzylamines in good to excellent yields and excellent enantioselectivities (up to 99% ee) is disclosed. In particular, excellent scope with alkylimines was observed for the first time. The synthetic utility of the products was demonstrated in the first enantioselective synthesis of a dual orexin receptor antagonist, a compound that contains an amine-bearing stereocenter adjacent to a bis-ortho-functionalized arene.
- Shikora, Jonathan M.,Chemler, Sherry R.
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supporting information
p. 2133 - 2137
(2018/04/30)
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- Verkade's Superbase as an Organocatalyst for the Strecker Reaction
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Proazaphosphatranes -Verkade's superbases- proved to be efficient organocatalysts for the Strecker reaction between protected imines and trimethylsilyl cyanide (TMSCN). Excellent to quantitative yields were reached and, compared to other systems, only low
- Yang, Jian,Chatelet, Bastien,Ziarelli, Fabio,Dufaud, Véronique,Hérault, Damien,Martinez, Alexandre
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supporting information
p. 6328 - 6332
(2018/11/23)
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- Iridium-Catalyzed Highly Regioselective and Diastereoselective Allylic Etherification to Access cis-2,6-Disubstituted Dihydropyridinones
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A highly regio- and diastereoselective method to access cis-2,6-disubstituted dihydropyridinones under mild conditions by an iridium-catalyzed allylic etherification is reported. cis-2,6-Disubstituted dihydropyridinones are important precursors for the de novo synthesis of the corresponding piperidine alkaloids and iminosugars. This strategy features a broad substrate scope, high yields, and excellent regio- and diastereoselectivities. A π-allyl-Ir intermediate is involved in the mechanism. The strong A1,3-strain from the tosyl group may also favor the formation of cis-products in this transformation.
- Song, Wangze,Li, Ming,Zheng, Nan,Ullah, Karim,Li, Junhao,Dong, Kun,Zheng, Yubin
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p. 12822 - 12830
(2018/10/15)
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- Palladium-Catalyzed Direct Intramolecular C-N Bond Formation: Access to Multisubstituted Dihydropyrroles
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A palladium-catalyzed intramolecular amination of alkenes with retention of olefin functionalization was achieved under mild reaction conditions. In the presence of palladium catalyst, the tosyl-protected amine can directly couple with a double bond to provide versatile dihydropyrrole derivatives in moderate to excellent yields.
- Jiang, Bing,Meng, Fei-Fan,Liang, Qiu-Ju,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 914 - 917
(2017/02/26)
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- Asymmetric Arylation of Imines Catalyzed by Heterogeneous Chiral Rhodium Nanoparticles
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Asymmetric arylation of aldimines catalyzed by heterogeneous chiral rhodium nanoparticles has been developed. The reaction proceeded in aqueous media without significant decomposition of the imines by hydrolysis to afford chiral (diarylmethyl)amines in high yields with outstanding enantioselectivities. This catalyst system exhibited the highest turnover number (700) in heterogeneous catalysts reported to date for these reactions. The reusability of the catalyst was also demonstrated.
- Yasukawa, Tomohiro,Kuremoto, Tatsuya,Miyamura, Hiroyuki,Kobayashi, Sh?
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supporting information
p. 2716 - 2718
(2016/06/15)
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- Aza-Morita-Baylis-Hillman reactions catalyzed by a cyclopropenylidene
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Catalysis using a bis(dialkylamino)cyclopropenylidene (BAC) has been developed, which relies on a formal umpolung activation of Michael acceptor pro-nucleophiles. Various aza-Morita-Baylis-Hillman reactions between aromatic, heteroaromatic, or aliphatic imines and acyclic or cyclic α,β-unsaturated ketones and carboxylic acid derivatives have been catalyzed by a BAC under mild conditions. Functionalities such as unprotected amino and hydroxy groups have been tolerated. The catalyst loading was decreased to 1 mol% without loss of activity. The BAC catalyst was shown to be substantially more active than a cyclic (alkyl)(amino) carbene (CAAC), N-heterocyclic carbenes (NHCs), and P- or N-centered Lewis bases.
- Lu, Xun,Schneider, Uwe
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supporting information
p. 12980 - 12983
(2016/11/09)
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- Chemoselective Boron-Catalyzed Nucleophilic Activation of Carboxylic Acids for Mannich-Type Reactions
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The carboxyl group (COOH) is an omnipresent functional group in organic molecules, and its direct catalytic activation represents an attractive synthetic method. Herein, we describe the first example of a direct catalytic nucleophilic activation of carbox
- Morita, Yuya,Yamamoto, Tomohiro,Nagai, Hideoki,Shimizu, Yohei,Kanai, Motomu
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supporting information
p. 7075 - 7078
(2015/06/25)
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- A gold-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade: Syntheses of medium-sized heterocycles
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The synthesis of medium-sized heterocycles possessing a trans double bond is still a challenge. Herein, gold(I)-catalyzed 1,2-acyloxy migration/intramolecular cyclopropanation/ring enlargement cascade reaction of furans has been developed, providing highly efficient access to ten- and eleven-membered heterocycles with a broad substrate scope under mild reaction conditions. The reaction outcome features high chemoselectivity at the C5-position of furan. Moreover, a trans-double bond was embodied in the medium ring system.
- Sun, Yin-Wei,Tang, Xiang-Ying,Shi, Min
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supporting information
p. 13937 - 13940
(2015/09/07)
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- 3-PIPERIDONE COMPOUNDS AND THEIR USE AS NEUROKININ-1 (NK1) RECEPTOR ANTAGONISTS
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The invention relates to 3-piperidone compounds, and in particular, to (2S)-phenyl-3-piperidone and its synthesis method. Use of the thus-synthesized 3-piperidone compounds as potent neurokinin-1 (NK1) receptor antagonists is also provided.
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Paragraph 0058
(2014/09/29)
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- Biomass derived furfural-based facile synthesis of protected (2S)-phenyl-3-piperidone, a common intermediate for many drugs
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An efficient synthetic route towards tosyl-protected (2S)-phenyl-3- piperidone, a common intermediate for many drugs, has been developed in 5 steps in 54% yield from biomass derived furfural. The synthetic utility of the piperidone core structure was demonstrated with the synthesis of a NK 1 receptor antagonist. This journal is the Partner Organisations 2014.
- Koh,Wang,Huang,Loh
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supporting information
p. 8324 - 8327
(2014/07/22)
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- Highly enantioselective rhodium-catalyzed [2+2+2] cycloaddition of diynes to sulfonimines
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A new asymmetric [2+2+2] cycloaddition of diynes to sulfonimines under rhodium catalysis that provides the corresponding enantioenriched 1,2-dihydropyridines in good yields is described.
- Amatore, Muriel,Lebuf, David,Malacria, Max,Gandon, Vincent,Aubert, Corinne
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supporting information
p. 4576 - 4579
(2013/05/22)
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- One-pot preparation of homopropargylic N-sulfonylamines catalyzed by zinc powder
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A new one-pot method for synthesis of homopropargylic N-sulfonylamines from aldehydes catalyzed by zinc powder is described. The procedure is lauded by its simplicity, good yields, and adaptability to a wide variety of aldehydes.
- Wu, Chao,Huang, Wangyong,He, Weimin,Xiang, Jiannan
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supporting information
p. 1233 - 1234
(2013/10/22)
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- Hydrocyanation of sulfonylimines using potassium hexacyanoferrate(II) as an eco-friendly cyanide source
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An efficient and eco-friendly method for hydrocyanation of sulfonylimines via one-pot two-step procedure using potassium hexacyanoferrate(II) as a cyanide source, benzoyl chloride as a promoter, and potassium carbonate as a base is described. This protocol has the features of using nontoxic, nonvolatile and inexpensive cyanide source, high yield, and simple work-up procedure.
- Li, Zheng,Li, Rongzhi,Zheng, Huanhuan,Wen, Fei,Li, Hongbo,Yin, Junjun,Yang, Jingya
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p. 1739 - 1743
(2014/01/06)
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- Synthesis of N-sulfonylimines using CeCl3 under neutral conditions
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An efficient and environmentally benign method for the synthesis of N-sulfonylimines is reported. Condensation of aryl sulfonamides with different aromatic aldehydes and ketones gave N-sulfonylimines in good to excellent yields in the presence of 10 mol% CeCl3 as catalyst. This method can be used with both aldehydes and ketones.
- Zhu, Xun,Wei, Yunyang
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experimental part
p. 363 - 364
(2012/09/22)
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- Enantioselective Friedel-Crafts reactions between phenols and N-tosylaldimines catalyzed by a leucine-derived bifunctional catalyst
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Enantioselective Friedel-Crafts reactions between phenols and N-tosylaldimines were developed using a bifunctional catalyst readily prepared from l-leucine. The chiral benzylic amine products were obtained in high yields (up to 96% yield) and good to high enantiomeric excesses (up to 95% ee).
- Li, Guo-Xing,Qu, Jin
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supporting information; experimental part
p. 5518 - 5520
(2012/07/01)
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- Nucleophilic addition of regioselectively lithiated indoline with aldimines for the syntheses of 2- and 7-indolinyl methanamine derivatives
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Indolines bearing different N-protecting groups (N-Tbf and N-Boc) were deprotonated regioselectively at C-2 (sp3 hybridized ortho-H) and C-7 (sp2 hybridized para-H) of the indoline ring, respectively. The generated organolithium intermediates reacted with aldimines to give the desired products in good yields with excellent anti-diastereoselectivities (>99:1). The produced N-Ts-(1-Tbf-indolin-2-yl)methanamine was facilely transformed to a fused heterocyclic compound.
- Cheng, Liang,Liu, Li,Li, Chuan,Jia, Han,Wang, Dong,Chen, Yong-Jun
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supporting information; experimental part
p. 4004 - 4007
(2012/09/05)
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- Rh-catalyzed C-C cleavage of benzyl/allylic alcohols to produce benzyl/allylic amines or other alcohols by nucleophilic addition of intermediate rhodacycles to aldehydes and imines
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We report three transformations: 1) direct transformation from biarylmethanols into biarylmethylamines; 2) direct transformation from one biarylmethanol into another biarylmethanol; 3) direct transformation from allylic alcohols into allylic amines. These transformations are based on pyridyl-directed Rh-catalyzed C-C bond cleavage of secondary alcohols and subsequent addition to C=X (X=N or O) double bonds. The reaction conditions are simple and no additive is required. The driving force of C-C bond cleavage is the formation of the stable rhodacycle intermediate. Other directing groups, such as the pyrazolyl group, can also be used although it is not as efficient as the pyridyl group. We carried out in-depth investigations for transformation 1 and found that: 1) the substrate scope was broad and electron-rich alcohols and electron-deficient imines are more efficient; 2) as the leaving group, aldehyde had no significant impact on either the C-C bond cleavage or the whole transformation; 3) mechanistic studies (intermediate isolation, in situ NMR spectroscopic studies, competing reactions, isotopic labeling experiments) implied that: i) The C-C cleavage was very efficient under these conditions; ii) there is an equilibrium between the rhodacycle intermediate and the protonated byproduct phenylpyridine; iii) the addition step of the rhodacycle intermediate to imines was slower than the C-C cleavage and the equilibrium between the rhodacycle and phenylpyridine; iv) the whole transformation was a combination of two sequences of C-C cleavage/nucleophilic addition and C-C cleavage/protonation/C-H activation/nucleophilic addition, with the latter being perhaps the main pathway. We also demonstrated the first example of cleavage of an C(alkenyl)-C(benzyl) bond. These transformations showed the exchange (or substitution) of the alcohol group with either an amine or another alcohol group. Like the "group transplant", this method offers a new concept that can be used to directly synthesize the desired products from other chemicals through reorganization of carbon skeletons.
- Zhang, Xi-Sha,Li, Yang,Li, Hu,Chen, Kang,Lei, Zhi-Quan,Shi, Zhang-Jie
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supporting information
p. 16214 - 16225
(2013/02/21)
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- Efficient and convenient preparation of N-tosylimines catalyzed by indium trichloride
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A new method for preparation of N-tosylimines by InCl3-mediated condensation of aldehydes with p-toluenesulfonamide in refluxing benzene is reported. The procedure is lauded by its simplicity, mild reaction conditions, excellent yields and adap
- Deng, Gui Sheng,Zou, Jing Yuan,Sun, Teng Fei
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scheme or table
p. 511 - 514
(2012/01/05)
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- Nucleophilic trifluoromethylation with organoboron reagents
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Potassium trialkoxy(trifluoromethyl)borates are shown to behave as convenient reagents for nucleophilic trifluoromethylation of non-enolizable aldehydes and N-tosylimines to give CF3-substituted alcohols and N-tosylamines in good yields.
- Levin, Vitalij V.,Dilman, Alexander D.,Belyakov, Pavel A.,Struchkova, Marina I.,Tartakovsky, Vladimir A.
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supporting information; body text
p. 281 - 284
(2011/02/26)
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- Dimethylsulfoxide-promoted Strecker reaction of N-tosylaldimines with cyanoformate
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A metal-free method for performing the Strecker reaction of N-tosylaldimines with ethyl cyanoformate in dimethylsulf-oxide (DMSO) has been developed. Various types of N-tosyl-aldimines undergo the cyanation to provide the N-protected -amino nitriles. This
- Kadam, Santosh T.,Thirupathi, Ponnaboina,Kim, Sung Soo
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scheme or table
p. 919 - 923
(2011/05/07)
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- Synthesis of α-sulfanyl-β-amino acid derivatives by using nanocrystalline magnesium oxide
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The Mannich-type reaction between alkyl, aryl and heterocyclic aldimines and sulfonium salts for the synthesis of α-sulfanyl-β-amino acid derivatives by using nanocrystalline magnesium oxide (NAP-MgO) is described. These products are obtained in moderate to high yields with moderate diastereoselectivities. The configuration of ethyl-3-{[(4-methylphenyl)sulfonyl] amino}-2-(methylsulfanyl)-3-(4-nitrophenyl)propanoate (major isomer) has been confirmed by X-ray diffraction technique to be anti, and consistent with the assignment based on 1H NMR spectroscopy. These α-sulfanyl- β-amino acid derivatives are important building blocks for pharmaceuticals with potent biological activity.
- Kantam, M. Lakshmi,Mahendar, Koosam,Sreedhar, Bojja,Choudary, Boyapati. M.,Bhargava, Suresh K.,Priver, Steven H.
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experimental part
p. 5042 - 5052
(2010/08/20)
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- The reaction of N-tosyl imines with heteroaromatic compounds: A new access to triheteroarylmethanes
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Useful triheteroarylmethanes were prepared by the double Friedel-Crafts reaction of a wide variety of aromatic N-tosyl imines with furan, thiophene, and pyrrole in the presence of Cu(OTf)2 and Montmorillonite K-10 clay catalysts.
- Temelli, Baris,Tasgin, Dilek Isik,Unaleroglu, Canan
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body text
p. 6765 - 6768
(2010/10/01)
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- Iron-catalyzed sulfonylimine synthesis under neutral conditions
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A convenient FeCl3-catalyzed synthesis of N-sulfonylimines via the condensation of aldehydes with N-sulfonylamides in mild and neutral conditions (in ethanol at room temperature) is reported. This procedure constitutes the first iron-catalyzed
- Wu, Xiao-Feng,Vovard-Le Bray, Chloé,Bechki, Lazhar,Darcel, Christophe
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experimental part
p. 7380 - 7384
(2009/12/06)
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- Enantioselective organocatalytic anti-Mannich-type reaction of N-unprotected 3-substituted 2-oxindoles with aromatic N-Ts-aldimines
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(Chemical Equation Presented) The modified cinchona alkaloid-catalyzed direct Mannich-type reaction of N-unprotected 2-oxindoles with N-Ts-imine was developed to afford anti-3,3-disubstituted 2-oxindoles with vicinal chiral quaternary and tertiary carbon
- Cheng, Liang,Liu, Li,Jia, Han,Wang, Dong,Chen, Yong-Jun
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supporting information; experimental part
p. 4650 - 4653
(2009/09/25)
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- Base and copper(i) catalyzed Mannich, alkyne hydroamination cascades for the direct synthesis of 2-methylenepyrrolidines
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An efficient, simple-to-perform, one-pot reaction cascade to 2-methylenepyrrolidines from p-toluenesulfonyl protected imines and propargylated malonates under a combination of base and copper(i) catalysis is reported.
- Wang, Hai-Fei,Yang, Ting,Xu, Peng-Fei,Dixon, Darren J.
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supporting information; experimental part
p. 3916 - 3918
(2010/01/06)
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- N-Heterocyclic carbene catalysed β-lactam synthesis
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N-Heterocyclic carbenes promote the formal [2+2] cycloaddition of ketenes with N-tosyl imines to give the corresponding β-lactams in good to excellent isolated yields; chiral NHCs give β-lactams in high e.e. after crystallisation.
- Duguet, Nicolas,Campbell, Craig D.,Slawin, Alexandra M. Z.,Smith, Andrew D.
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supporting information; experimental part
p. 1108 - 1113
(2009/02/05)
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- Synthesis of 3-sulfonyloxypyridines: Oxidative ring expansion of α-furyl-sulfonamides and N→O sulfonyl transfer
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N-Sulfonyl pyridinones derived from α-furylsulfonamides may be aromatised with concomitant N→O sulfonyl transfer to produce 3-sulfonyloxypyridines. Georg Thieme Verlag Stuttgart.
- Hodgson, Robert,Kennedy, Andrew,Nelson, Adam,Perry, Alexis
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p. 1043 - 1046
(2008/02/13)
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- A convenient and efficient method for the preparation of N-sulfonyl aldimines from aromatic aldehydes under solvent-free conditions
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Condensation of a variety of aromatic aldehydes with sulfonamides in the presence of silica chloride by heating afforded novel functionally varied aromatic N-sulfonyl aldimines in good to excellent yields. Copyright Taylor & Francis Group, LLC.
- Hasaninejad, Alireza,Sharghi, Hashem
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p. 873 - 880
(2007/10/03)
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- A Solvent-Free Procedure for Synthesis of N-Sulfonylimines Using Microwave Irradiation Catalyzed by ZrO2/S2O2- 8 Solid Superacid
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A solvent-free synthesis of N-sulfonylimines from aldehydes with sulfonamides is described using ZrO2/S2O2- 8 as catalyst under microwave irradiation. This method is fast and high yielding for a range of substrates.
- Jin, Tongshou,Feng, Guoliang,Yang, Mina,Li, Tongshuang
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p. 1277 - 1283
(2007/10/03)
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- A flexible approach toward trisubstituted piperidines and indolizidines: Synthesis of 6-epi-indolizidine 223A
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2,5,6-Trisubstituted piperidines are readily prepared by a combination of an aza-Achmatowicz oxidation of a furyl-substituted benzenesulfonamide followed by a conjugate addition to the resulting 2H-pyridone and subsequent addition of various nucleophiles
- Harris, Joel M.,Padwa, Albert
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p. 4371 - 4381
(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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- Stereoselective synthesis of 2,5,6-trisubstituted piperidines.
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[reaction: see text] A short and efficient synthesis of 2,5,6-trisubstituted piperidines was achieved by a combination of an aza-Achmatowicz oxidation of a furyl benzenesulfonamide, conjugate addition to the resulting 2H-pyridinone, and subsequent additio
- Harris, Joel M,Padwa, Albert
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p. 2029 - 2031
(2007/10/03)
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