- The Synthesis of Butenamides and Thiobutenamide by an Organosamarium Reagent
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An organosamarium reagent reacts with isocyanates (or isothiocyanate) to afford butenamides (or thiobutenamide) in THF.
- Yu, Mingxin,Zhang, Yongmin,Qian, Cangtao
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- Dehydrogenative Allylic Aminations of But-3-enoic Acid Derivatives
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Two complementary Pd-catalyzed protocols enabling the γ-selective intermolecular allylic amination of but-3-enoic acid derivatives are reported. These transformations can be successfully achieved via either a direct Pd(II)-catalyzed protocol or by way of a one-pot Pd(II)/Pd(0)-catalyzed sequence, depending on the nature of the nitrogen nucleophile used.
- Diamante, Daria,Gabrieli, Sara,Benincori, Tiziana,Broggini, Gianluigi,Oble, Julie,Poli, Giovanni
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- Palladium-catalyzed tandem bis-allylation of isocyanates
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matrix presented A tandem bis-allylation of p-toluenesulfonyl isocyanate can be achieved by palladium-catalyzed three-component coupling reaction with allylstannanes and allyl chlorides. A high level of regioselectivity can be obtained by the appropriate choice of the allylic substituents. The reaction mechanism and the regiochemistry of the reaction can be explained by formation of an amphoteric bis-allylpalladium intermediate. This bis-allylpalladium intermediate undergoes an initial electrophilic attack on one of the allyl moieties followed by a nucleophilic attack on the other.
- Solin, Niclas,Narayan, Sanjay,Szabo, Kalman J.
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- Synthesis of gem -Difluoroalkenes via a Sequence of Hydroboration and 1,2-Elimination of α,β-Unsaturated Carbonyls
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We reported a simple protocol for the synthesis of gem -difluoroalkenes via a reaction sequence of hydroboration and 1,2-elimination of α,β-unsaturated carbonyl substrates under mild conditions. Two steps of this method could be executed in one pot. The β-CF 2H- and β-CFH 2-α,β-unsaturated carbonyls can be obtained smoothly from the α,β-unsaturated gem -difluoroamide with NaH as the base and via a boration-1,2-elimination sequence.
- An, Shiyun,Zhang, Jinlong,Jiang, Gaoxi
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- Nickel-Catalyzed Reductive Cross-Coupling of N-Acyl and N-Sulfonyl Benzotriazoles with Diverse Nitro Compounds: Rapid Access to Amides and Sulfonamides
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Herein we report a Ni-catalyzed reductive transamidation of conveniently available N-acyl benzotriazoles with alkyl, alkenyl, and aryl nitro compounds, which afforded various amides with good yields and a broad substrate scope. The same catalytic reaction conditions were also applicable for N-sulfonyl benzotriazoles, which could undergo smooth reductive coupling with nitroarenes and nitroalkanes to afford the corresponding sulfonamides.
- Qu, Erdong,Li, Shangzhang,Bai, Jin,Zheng, Yan,Li, Wanfang
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supporting information
p. 58 - 63
(2021/12/27)
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- Photocatalyzed Triplet Sensitization of Oximes Using Visible Light Provides a Route to Nonclassical Beckmann Rearrangement Products
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Oximes are valuable synthetic intermediates for the preparation of a variety of functional groups. To date, the stereoselective synthesis of oximes remains a major challenge, as most current synthetic methods either provide mixtures of E and Z isomers or furnish the thermodynamically preferred E isomer. Herein we report a mild and general method to achieve Z isomers of aryl oximes by photoisomerization of oximes via visible-light-mediated energy transfer (EnT) catalysis. Facile access to (Z)-oximes provides opportunities to achieve regio- and chemoselectivity complementary to those of widely used transformations employing oxime starting materials. We show an enhanced one-pot protocol for photocatalyzed oxime isomerization and subsequent Beckmann rearrangement that enables novel reactivity with alkyl groups migrating preferentially over aryl groups, reversing the regioselectivity of the traditional Beckmann reaction. Chemodivergent N- or O- cyclizations of alkenyl oximes are also demonstrated, leading to nitrones or cyclic oxime ethers, respectively.
- Zhang, Xiao,Rovis, Tomislav
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supporting information
p. 21211 - 21217
(2021/12/27)
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- Copper-catalyzed asymmetric cyanation of alkenes via carbonyl-assisted coupling of alkyl-substituted carbon-centered radicals
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Based on a copper-catalyzed radical relay strategy, the first copper-catalyzed asymmetric cyanation of alkyl-substituted alkenes has been developed. The reaction, featuring mild reaction conditions and excellent functional group compatibilities, provides
- Zhou, Song,Zhang, Guoyu,Fu, Liang,Chen, Pinhong,Li, Yibiao,Liu, Guosheng
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supporting information
p. 6299 - 6303
(2020/10/02)
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- A practical copper-catalyzed approach to β-lactams: via radical carboamination of alkenyl carbonyl compounds
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Functionalized β-lactams are highly important motifs in synthetic chemistry. We report an efficient and novel approach to the synthesis of β-lactams via a copper(i)-catalyzed cascade process involving C(benzyl)-H radical abstraction, intermolecular alkene addition, and intramolecular amination reaction. Variously substituted alkenes were synthesized from vinylacetic acid, leading to the corresponding β-lactams in moderate to good yields. Preliminary studies indicate that the reaction undergoes a free radical mechanism via a Cu(i)/Cu(ii)/Cu(iii) catalytic cycle.
- Shi, Peng,Wang, Jie,Gan, Zixu,Zhang, Jingyu,Zeng, Runsheng,Zhao, Yingsheng
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supporting information
p. 10523 - 10526
(2019/09/06)
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- Anti-Markovnikov Hydroazidation of Alkenes by Visible-Light Photoredox Catalysis
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The anti-Markovnikov hydroazidation of alkenes has been accomplished under visible-light irradiation by using [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as the photocatalyst and trimethylsilyl azide as the azidating agent. The reactions were greatly facilitated by water, the beneficial effect of which can be attributed to its participation in the reaction as the hydrogen donor, as indicated by deuterium isotope experiments. The reactions proceed under solvent free conditions in the presence of water. 4-Dimethylaminopyridine also exhibited a beneficial effect on the reactions. The present method enabled hydroazidation of several types of unactivated alkenes with good yields and high regioselectivity.
- Wang, Juan-Juan,Yu, Wei
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supporting information
p. 3510 - 3514
(2019/02/19)
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- Three component reaction of aryl diazonium salt with sulfonamide & actonitrile to synthesize N-sulfonyl amidine
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A new method was developed to prepare N-sulfonyl amidine compounds through three-component reaction of aryl diazonium salts with sulfonamides and acetonitrile, in which, nitrilium ion intermediate, generated from the reaction of aryldiazonium salt with nitrile, was subsequently trapped by sulfonamides. A series of N-sulfonyl amidine derivatives were synthesized by using various types of aryl diazonium salts, sulfonamides and nitriles. In addition, indolyl imine products could also be prepared by using indole as the nucleophile to trap nitrilium ion intermediate.
- Zhang, Yuan,Chen, Zili
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supporting information
p. 4183 - 4186
(2018/10/24)
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- Useful four-carbon synthons en route to monastrol analogs
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A simple protocol has been established for the preparation of a family of crystalline N-aryl γ-hydroxycrotonamides, useful four-carbon synthons. These were further elaborated to analogs of monastrol having variant ester sidechains, that were evaluated for their anticancer activity employing the NCI 60 cell line panel.
- Abdou, Amr M.,Botros,Hassan, Rasha A.,Kamel, Mona M.,Taber, Douglass F.,Taher, Azza T.
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p. 139 - 146
(2015/02/18)
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- Reaction of organozinc halides with aryl isocyanates
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Reformatsky reagent, benzylzinc bromide or alkylzinc iodides react with aryl isocyanates directly to give corresponding N-substituted carbamates under mild reaction conditions. However, the reaction of allylzinc bromide or propargylzinc bromide with aryl isocyanates produces the corresponding N-substituted amides. The reactions provide alternative methods for the synthesis of N-substituted carbamates or amides.
- Yang, Haoran,Huang, Danfeng,Wang, Ke-Hu,Xu, Changming,Niu, Teng,Hu, Yulai
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supporting information
p. 2588 - 2593
(2013/03/28)
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- Synthesis of β,γ-unsaturated primary amides from α,β-unsaturated acids and investigation of the mechanism
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α,β-Unsaturated acids, through their acid chlorides, react with tritylamine in the presence of triethylamine under mild conditions, to afford in high yield and high regioselectivity the corresponding β,γ- unsaturated tritylamides. Detritylation with TFA generates quantitatively β,γ-unsaturated primary amides. An investigation of this deconjugative isomerization was performed.
- Theodorou, Vassiliki,Gogou, Marina,Philippidou, Maria,Ragoussis, Valentine,Paraskevopoulos, Georgios,Skobridis, Konstantinos
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experimental part
p. 5630 - 5634
(2011/08/22)
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- One-pot amide synthesis from allyl or benzyl halides and amines by Pd-catalysed carbonylation
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Amides can be prepared from allyl or benzyl halides and primary or secondary amines, using Pd(0) catalyst under CO pressure, in a one-pot synthesis. The reaction proceeds through the acyl palladium halide formation which undergoes an acylic nucleophilic substitution from the amine.
- Troisi, Luigino,Granito, Catia,Rosato, Francesca,Videtta, Valeria
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experimental part
p. 371 - 373
(2010/03/24)
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- Reductive dehalogenation of 4-halogenomethyl azetidin-2-one derivatives. Synthesis of (4-oxo-azetidin-2-yl)acetonitriles
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The stability of the β-lactam ring under reductive conditions was examined in order to find a selective method for the synthesis of (4-oxo-azetidin-2-yl)acetonitrile derivatives. Fifteen variously substituted 4-halogenomethyl-β-lactam derivatives were syn
- Boros, Eva,Bertha, Ferenc,Fetter, Jozsef,Vida, Laszlo,Kajtar-Peredy, Maria,Czira, Gabor
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p. 558 - 563
(2007/10/03)
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- Allyl- and propargylchromium reagents generated by a chromium(III) ate-type reagent as a reductant and their reactions with electrophiles
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A chromium ate-type reagent 'Bu5CrLi2' reacts with allylic and propargylic phosphates to generate the corresponding allyl- and propargylchromium (propargyl = prop-2-ynyl) reagents which further react with a variety of electrophiles such as aldehydes, ketones, imines, and isocyanates to afford the corresponding adducts in high yields.
- Hojo,Sakuragi,Okabe,Hosomi
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p. 357 - 358
(2007/10/03)
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- Synthesis and evaluation of antitumor activity of arylamides and cyclohexylamides of isomeric 3-chloro-4-(2-chloroethylthio)butanoic- and 4-chloro-3-(2-chloroethylthio)butanoic acids
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In the hope to find antitumor candidates among di-(2-chloroethyl)sulfides it was found that only 3-chloro-4-(2-chloroethylthio)butanoic (3-chloro) and 4-chloro-3-(2-chloroethylthio)butanoic (4-chloro) acids possess definite alkylating ability which is sug
- Vektariene, Ausra,Palaima, Algirdas,Simkeviciene, Vitalija
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p. 217 - 222
(2007/10/03)
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- REACTIONS OF TITANOCENE ALLYLS
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Cp2Tiη3-allyl and Cp2Tiη3-1-methylallyl react with carbon dioxide, phenylisocyanate, benzalaniline, acetone and acetonitrile to give insertion products which are formed via allyl migration.Normal insertion is observed with 2,6-xylylisocyanide.C
- Klei, E.,Teuben, J.H.,De Liefde Meijer, H.J.,Kwak, E.J.,Bruins, A.P.
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p. 327 - 339
(2007/10/02)
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- Titanium-promoted Allyl Transfer to Carbon Monoxide and Other Unsaturated Molecules
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Carbonylation of Cp2Ti-(?-allyl) yields Cp2Ti(CO)2 and triallylmethanol; reactions of Cp2Ti-(?-allyl) and Cp2Ti-(?-1-methylallyl) with other ligands proceed via insertion or allyl-elimination pathways.
- Klei, Bert,Teuben, Jan H.,Meijer, Henk J. de Liefde
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p. 342 - 344
(2007/10/02)
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