- Desymmetrization of N-Sulfonated Aziridines by Alkyllithium Reagents in the Presence of Chiral Ligands
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The stereochemical course of the rearrangement of the N-sulfonylaziridines 5, 15, and 25 in the presence of s-BuLi/(-)-sparteine to the bicyclic sulfonamides 4, 16, and 17, respectively, has been investigated chemically and by X-ray structure analysis. Th
- Mueller, Paul,Riegert, David,Bernardinelli, Gerald
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- Transformation of allyl stannanes into allyl amines using [N-(p-toluenesulfonyl)imino]-phenyliodinane
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Reaction of allyl stannanes with PhI = NTs in the presence of 10mol % of Cu(OTf)2 provides a direct route for the preparation of N-tosylallyl amines in moderate yields.
- Kim,Kim,Choi,Mang,Lee
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Read Online
- Is the Electrophilicity of the Metal Nitrene the Sole Predictor of Metal-Mediated Nitrene Transfer to Olefins? Secondary Contributing Factors as Revealed by a Library of High-Spin Co(II) Reagents
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Recent research has highlighted the key role played by the electron affinity of the active metal-nitrene/imido oxidant as the driving force in nitrene additions to olefins to afford valuable aziridines. The present work showcases a library of Co(II) reage
- Kalra, Anshika,Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Ai, Lin,Sanakis, Yiannis,Raptopoulos, Grigorios,Mohapatra, Sudip,Choudhury, Amitava,Sun, Zhicheng,Cundari, Thomas R.,Stavropoulos, Pericles
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p. 1974 - 1996
(2021/06/28)
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- The aza-wharton reaction: Syntheses of cyclic allylic amines and vicinal hydroxyamines from the respective acylaziridines
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The Wharton reaction, initially described for acyl epoxides, has been studied using the structurally similar aziridines. By this reaction, a range of cyclic allylic amines and vicinal amino alcohols have been prepared stereoselectively and, in some cases, enantiomerically pure.
- Silva, Saúl,Rodrigues, Paula,Bento, Isabel,Maycock, Christopher D.
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p. 3067 - 3074
(2015/03/30)
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- A heterogeneous mercury salt catalyst stabilized by m-carbaborane
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Development of reusable heterogeneous catalysts has attracted a great deal of attention for both environmental and atom-economic reasons. In particular, a considerable amount of work has focused on reusable heavy- and rare-metal catalysts in order to limit the use and/or minimize the generation of problematic metal waste upon disposal. Herein is reported the development of a new polysiloxane-linked m-carbaboranylmercury (SiCB-Hg) catalyst, which can be used for various mercury salt-induced reactions such as the regioselective cyclization of 1,3-dienes and allyl alcohols, the intermolecular amination of allyl alcohols with sulfamates, and the cycloisomerization of alkynes. The catalyst can be completely recovered by simple filtration, with residual mercury in the filtrate 0.001% (nearly the quantitative limit). Furthermore, the catalyst can be reactivated by treatment with aqueous HCl and then AgOTf for reuse.
- Yamamoto, Hirofumi,Yamasaki, Naoto,Hamauchi, Hiroshi,Shiomi, Shinya,Sasaki, Ikuo,Seyama, Koichiro,Mima, Yasuko,Nakano, Mayo,Kawakami, Takashige,Miyataka, Hideki,Kasai, Yusuke,Imagawa, Hiroshi
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p. 94737 - 94742
(2015/11/24)
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- A versatile tripodal Cu(I) reagent for C-N bond construction via nitrene-transfer chemistry: Catalytic perspectives and mechanistic insights on C-H aminations/amidinations and olefin aziridinations
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A CuI catalyst (1), supported by a framework of strongly basic guanidinato moieties, mediates nitrene-transfer from PhI=NR sources to a wide variety of aliphatic hydrocarbons (C-H amination or amidination in the presence of nitriles) and olefins (aziridination). Product profiles are consistent with a stepwise rather than concerted C-N bond formation. Mechanistic investigations with the aid of Hammett plots, kinetic isotope effects, labeled stereochemical probes, and radical traps and clocks allow us to conclude that carboradical intermediates play a major role and are generated by hydrogen-atom abstraction from substrate C-H bonds or initial nitrene-addition to one of the olefinic carbons. Subsequent processes include solvent-caged radical recombination to afford the major amination and aziridination products but also one-electron oxidation of diffusively free carboradicals to generate amidination products due to carbocation participation. Analyses of metal- and ligand-centered events by variable temperature electrospray mass spectrometry, cyclic voltammetry, and electron paramagnetic resonance spectroscopy, coupled with computational studies, indicate that an active, but still elusive, copper-nitrene (S = 1) intermediate initially abstracts a hydrogen atom from, or adds nitrene to, C-H and C=C bonds, respectively, followed by a spin flip and radical rebound to afford intra- and intermolecular C-N containing products.
- Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Chi, Lingyu,Wang, Qiuwen,Choudhury, Amitava,Mathieson, Jennifer S.,Cronin, Leroy,Pardue, Daniel B.,Cundari, Thomas R.,Mitrikas, George,Sanakis, Yiannis,Stavropoulos, Pericles
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supporting information
p. 11362 - 11381
(2014/09/17)
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- DDQ-mediated direct oxidative coupling of amides with benzylic and allylic sp3 C-H bonds under metal-free conditions
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A simple and efficient method for the direct oxidative coupling of amides with benzylic and allylic sp3 C-H bonds using DDQ as an oxidant is described. A range of amides including benzamide, benzyl carbamate, and substituted sulfonamides reacted efficiently with various benzylic and allylic substrates under metal free conditions to afford amidation products in good to excellent yields.
- Ramesh,Ramulu,Mukkanti,Venkateswarlu
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experimental part
p. 2904 - 2908
(2012/07/27)
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- Intermolecular amination of allyl alcohols with sulfamates: Effective utilization of mercuric catalyst
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Herein, we describe the intermolecular amination of allyl alcohols with sulfamates, which have been underutilized as nitrogen nucleophiles for allylic amination. Methyl sulfamate is a good nucleophile in the presence of mercuric triflate and efficiently generates monoallylation products in excellent yield at room temperature. Furthermore, the solid-supported mercuric catalyst silaphenyl mercuric triflate also showed remarkable catalytic activity for the allylic amination. Intermolecular amination of allyl alcohol with sulfamate as a modifiable nitrogen nucleophile is presented. Mercuric reagents act as highly efficient catalyst for the allylic amination, and the procedure was applied to the preparation of various amine derivatives. In many cases, the reaction can be carried out at room temperature and is applicable to a large range of allylic alcohols to give the monoallylated products in excellent yield. Copyright
- Yamamoto, Hirofumi,Ho, Elisabeth,Sasaki, Ikuo,Mitsutake, Mizuho,Takagi, Yuichi,Imagawa, Hiroshi,Nishizawa, Mugio
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supporting information; experimental part
p. 2417 - 2420
(2011/06/10)
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- Aerobic oxidative amination of unactivated alkenes catalyzed by palladium
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The first examples of palladium-catalyzed oxidative amination of unactivated alkyl olefins have been identified. To be successful, these reactions must be conducted under cocatalyst-free conditions that involve direct dioxygen-coupled turnover of the palladium catalyst. The oxidative amination products of norbornene and other cyclic alkenes implicate a cis-aminopalladation mechanism. Copyright
- Brice, Jodie L.,Harang, Jenna E.,Timokhin, Vitaliy I.,Anastasi, Natia R.,Stahl, Shannon S.
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p. 2868 - 2869
(2007/10/03)
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- Catalytic amination reactions mediated by Co(II) Schiff base complexes
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Co(acacen), 1, (acacen = 2,11-dihydroxy-4,9-dimethyl-5,8-diaza-2,4,8,10- dodecatetraene dianion) was found to be a highly efficient catalyst for the allylic amination of non activated alkenes, using N-(p-toluensulfonyl) iminophenyliodinane (PhINTs) as nitrene precursor. This reactivity has been extended to the less reactive C-H bond of toluene. The effect of reaction times and of added cosolvent on yields and selectivities was investigated. Under the best conditions, allylic amines were obtained in a 40-70% isolated yield. A complex derived from the stoichiometric reaction of Co(acacen), 1, with PhINTs has been isolated and spectroscopically characterized. Such a complex, although not able to transfer its NTs moiety to alkenes, is still active in catalyzing allylic amination of cyclohexene.
- Caselli, Alessandro,Gallo, Emma,Ragaini, Fabio,Oppezzo, Alessandro,Cenini, Sergio
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p. 2142 - 2148
(2007/10/03)
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- On the α-lithiation-rearrangement of N-toluensulfonyl aziridines: Mechanistic and synthetic aspects
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A detailed study of the rearrangement of five cycloalkene N-toluenesulfonyl (tosyl) aziridines using sec-butyllithium (with and without added ligands such as (-)-sparteine and TMEDA) has been carried out. Allylic sulfonamides were the main products from the cyclopentene and cyclohexene aziridines whereas bicyclic sulfonamides were obtained from the cycloheptene and cyclooctene aziridines. In most cases, p-toluenesulfonamide (TsNH 2) was produced as a by-product and a mechanistic explanation for its formation is forwarded. These reactions are believed to involve α-lithiation to a lithiated aziridine which can then partition through two pathways: (i) rearrangement to allylic or bicyclic sulfonamides via C-H insertion reactions or (ii) reductive alkylation to alkenes via attack by sec-butyllithium and subsequent elimination of TsNH2. In the (-)-sparteine reactions, the products were generated with 38-66% ee and the sense of asymmetric induction involved lithiation of the S-aziridine stereocentre. This is opposite to that observed with epoxides.
- O'Brien, Peter,Rosser, Clare M.,Caine, Darren
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p. 9779 - 9791
(2007/10/03)
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- Angular ligand constraint yields an improved olefin aziridination catalyst
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(Matrix presented) The use of a pyridinophane, a macrocycle composed of three pyridines linked, via all ortho positions through CH2 or CH2CH2 groups, bound to copper, gives good performance (rate and yield) catalyzing the
- Vedernikov, Andrei N.,Caulton, Kenneth G.
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p. 2591 - 2594
(2007/10/03)
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- Base-promoted elaboration of aziridines
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The base-promoted isomerization of aziridines to allyl amines is still an almost unknown reaction. However, the use of superbasic reagents has shown to be able to promote a regio- and stereoselective conversion of monocyclic and bicyclic sulfonyl aziridin
- Mordini, Alessandro,Russo, Francesco,Valacchi, Michela,Zani, Lorenzo,Degl'Innocenti, Alessandro,Reginato, Gianna
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p. 7153 - 7163
(2007/10/03)
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- Benzylic and allylic amination
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N-(p-Toluenesulfonyl)amino group can be directly introduced at allylic or benzylic carbon by treating alkenes or alkylarenes with t-butyl N-(p-toluenesulfonyl)peroxycarbamate in the presence of Cu(II) triflate.
- Kohmura, Yoshinori,Kawasaki, Ken-Ichi,Katsuki, Tsutomu
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p. 1456 - 1458
(2007/10/03)
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