- Dihalogenation of Alkenes Using Combinations of N-Halosuccinimides and Alkali Metal Halides
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A simple, efficient and eco-friendly method for the vicinal dihalogenation of alkenes is described. The reaction is performed with a combination of a N-halosuccinimide and an alkali metal halide using environmentally benign solvents such as acetic acid an
- Barrio, Pablo,García-Pedrero, Olaya,López-Matanza, Pablo,Rodríguez, Félix,Rubio-Presa, Rubén
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supporting information
p. 4762 - 4766
(2021/09/10)
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- Photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sulfinates
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A metal-free visible light photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates in moderate to high yields is described. The reaction proceeds in ethanol and uses eosin Y as a readily available photocatalyst in combination with nitrobenzene as an electron shuttle. Taking into account the number of steps involved (generation of the sulfonyl radical, its addition to the double bond, elimination of molecular nitrogen with formation of an iminyl radical, followed by its reduction and protonation) as well as the number of redox-active reaction partners involved, the selectivity of the process is quite impressive.
- Mulina, Olga M.,Ilovaisky, Alexey I.,Opatz, Till,Terent'ev, Alexander O.
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supporting information
(2021/01/11)
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- Electrosynthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates mediated by NH4I
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A wide range of N-unsubstituted enaminosulfones were obtained via electrochemical sulfonylation of vinyl azides with sulfonyl radicals generated from sodium sulfinates. The discovery of N-unsubstituted enaminosulfones synthesis is based on a unique ability of the azido group to eliminate the N2 molecule. The process is performed under constant current conditions in an experimentally convenient undivided electrochemical cell equipped with a graphite anode and a stainless steel cathode applying NH4I both as the redox catalyst and the supporting electrolyte.
- Mulina, Olga M.,Doronin, Mikhail M.,Terent'ev, Alexander O.
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supporting information
(2021/10/16)
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- Electrochemical Synthesis of O-Phthalimide Oximes from α-Azido Styrenes via Radical Sequence: Generation, Addition and Recombination of Imide-N-Oxyl and Iminyl Radicals with C?O/N?O Bonds Formation
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Electrochemically induced radical-initiated reaction of vinyl azides with N-hydroxyphthalimide resulting O-phthalimide oximes with challenging for organic chemistry N?O-N fragment has been discovered. The developed approach introduces in synthesis electrochemically generated O-centered imide-N-oxyl radicals as the coupling components. Sequential formation of C?O and N?O bonds was achieved via generation and selective addition of imide-N-oxyl radicals, followed by recombination with iminyl radicals. A wide range of O-phthalimide oximes was obtained with the yields up to 84percent. (Figure presented.).
- Paveliev, Stanislav A.,Churakov, Artem I.,Alimkhanova, Liliya S.,Segida, Oleg O.,Nikishin, Gennady I.,Terent'ev, Alexander O.
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supporting information
p. 3864 - 3871
(2020/07/30)
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- Asymmetric Nazarov Cyclizations of Unactivated Dienones by Hydrogen-Bond-Donor/Lewis Acid Co–Catalyzed, Enantioselective Proton-Transfer
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We report an enantioselective Nazarov cyclization catalyzed by chiral hydrogen-bond-donors in concert with silyl Lewis acids. The developed transformation provides access to tri-substituted cyclopentenones in high levels of enantioselectivity (up to 95% e.e.) from a variety of simple unactivated dienones. Kinetic and mechanistic studies are consistent with a reversible 4π-electrocyclization C?C bond-forming step followed by rate- and enantio-determining proton-transfer as the mode of catalysis. (Figure presented.).
- Metternich, Jan B.,Reiterer, Martin,Jacobsen, Eric N.
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supporting information
p. 4092 - 4097
(2020/09/01)
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- Zn-ProPhenol Catalyzed Enantioselective Mannich Reaction of 2 H-Azirines with Alkynyl Ketones
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The enantioselective Mannich reaction of 2H-azirines with alkynyl ketones is achieved under Zn-ProPhenol catalysis, delivering various aziridines with vicinal tetrasubstituted stereocenters in high yields with excellent enantioselectivities. The bimetalli
- Trost, Barry M.,Zhu, Chuanle
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supporting information
p. 9683 - 9687
(2020/12/21)
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- Preparation of a novel bromine complex and its application in organic synthesis
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Although molecular bromine (Br2) is a useful brominating reagent, it is not easy to handle. Herein, we describe the preparation of a novel air-stable bromine complex prepared from 1,3-dimethyl-2-imidazolidinone (DMI) and Br2, which was identified to be (DMI)2HBr3 by spectral and X-ray techniques. This complex was then used to brominate olefins, carbonyl compounds, and aromatics, as well as in the Hofmann rearrangement. Yields of reaction products using this complex were almost the same or superior to those using other bromine alternatives.
- Nishio, Yuya,Yubata, Kotaro,Wakai, Yutaro,Notsu, Kotaro,Yamamoto, Katsumi,Fujiwara, Hideki,Matsubara, Hiroshi
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p. 1398 - 1405
(2019/02/07)
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- A Cascade Suzuki-Miyaura/Diels-Alder Protocol: Exploring the Bifunctional Utility of Vinyl Bpin
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Cascade reactions are an important strategy in reaction design, allowing streamlining of chemical synthesis. Here we report a cascade Suzuki-Miyaura/Diels-Alder reaction, employing vinyl Bpin as a bifunctional reagent in two distinct roles: as an organoboron nucleo phile for cross-coupling and as a Diels-Alder dienophile. Merging these two reactions enables a rapid and operationally simple synthesis of functionalized carbocycles in good yield. The effect of the organoboron subtype on Diels-Alder regioselectivity was investigated and postsynthetic modifications were carried out on a model substrate. The potential for a complementary Heck/Diels-Alder process was also assessed.
- Cain, David L.,McLaughlin, Calum,Molloy, John J.,Carpenter-Warren, Cameron,Anderson, Niall A.,Watson, Allan J. B.
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supporting information
p. 787 - 791
(2019/04/25)
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- Rh(III)-Catalyzed C-H Activation-Initiated Directed Cyclopropanation of Allylic Alcohols
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We have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols initiated by alkenyl C-H activation of N-enoxyphthalimides to furnish substituted cyclopropyl-ketones. Notably, the traceless oxyphthalimide handle serves three functions: directing C-H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes.
- Phipps, Erik J. T.,Rovis, Tomislav
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supporting information
(2019/05/06)
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- Rh(III)-Catalyzed C-H Activation-Initiated Directed Cyclopropanation of Allylic Alcohols
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We have developed a Rh(III)-catalyzed diastereoselective [2+1] annulation onto allylic alcohols initiated by alkenyl C-H activation of N-enoxyphthalimides to furnish substituted cyclopropyl-ketones. Notably, the traceless oxyphthalimide handle serves three functions: Directing C-H activation, oxidation of Rh(III), and, collectively with the allylic alcohol, in directing cyclopropanation to control diastereoselectivity. Allylic alcohols are shown to be highly reactive olefin coupling partners leading to a directed diastereoselective cyclopropanation reaction, providing products not accessible by other routes.
- Phipps, Erik J.T.,Rovis, Tomislav
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supporting information
p. 6807 - 6811
(2019/05/10)
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- Rhodium(III)-Catalyzed Cyclopropanation of Unactivated Olefins Initiated by C-H Activation
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We have developed a rhodium(III)-catalyzed cyclopropanation of unactivated olefins initiated by an alkenyl C-H activation. A variety of 1,1-disubstituted olefins undergo efficient cyclopropanation with a slight excess of alkene stoichiometry. A series of mechanistic interrogations implicate a metal carbene as an intermediate.
- Phipps, Erik J. T.,Piou, Tiffany,Rovis, Tomislav
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supporting information
p. 1787 - 1790
(2019/09/09)
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- Cyrene as a Bio-Based Solvent for the Suzuki-Miyaura Cross-Coupling
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The Suzuki-Miyaura (SM) cross-coupling is the most broadly utilized Pd-catalyzed C-C bond-forming reaction in the chemical industry. A large proportion of SM couplings employ dipolar aprotic solvents; however, current sustainability initiatives and increasingly stringent regulations advocate the use of alternatives that exhibit more desirable properties. Here we describe the scope and utility of the bio-derived solvent Cyrene in SM cross-couplings and evaluate its suitability as a reaction medium for this benchmark transformation from discovery to gram scale.
- Wilson, Kirsty L.,Murray, Jane,Jamieson, Craig,Watson, Allan J. B.
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supporting information
p. 650 - 654
(2017/12/26)
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- Intermolecular Carboamination of Unactivated Alkenes
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Herein, we report the first example of group transfer radical addition of O-vinylhydroxylamine derivatives onto unactivated alkenes. By utilizing O-vinylhydroxylamine derivatives as both the N- and C-donors, this reaction enables intermolecular carboamination of unactivated alkenes in an atom economical fashion. As the process is initiated through N-radical addition followed by C-transfer, linear carboamination products are afforded. This differs from canonical radical carbofunctionalization of olefins, which typically favors branched product owing to initiation by C-radical addition.
- Zhang, Yu,Liu, Haidong,Tang, Luning,Tang, Hai-Jun,Wang, Lu,Zhu, Chuan,Feng, Chao
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supporting information
p. 10695 - 10699
(2018/09/06)
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- Synthesis, structure and photophysical properties of NIR aza-BODIPYs with [sbnd]F/[sbnd]N3/[sbnd]NH2 groups at 1,7-positions
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With 4-fluorostyrene as the starting material, symmetric/asymmetric fluorine-containing aza-difluoroboradiaza-s-indacenes (aza-BODIPYs) 3–6?at 1/7-position were successfully prepared. NaN3 undertook nucleophilic aromatic substitution via replac
- Jiang, Xin-Dong,Guan, Jian,Zhao, Jiuli,Le Guennic, Boris,Jacquemin, Denis,Zhang, Zhigang,Chen, Shangdong,Xiao, Linjiu
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p. 619 - 626
(2016/09/23)
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- One-Pot Strategy for Thiazoline Synthesis from Alkenes and Thioamides
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A convenient synthesis of a privileged pharmaceutical motif, thiazoline is accomplished. This reaction utilizes simple and readily available alkene and thioamide substrates in an intermolecular fashion via a simple one-pot procedure. A wide range of functional groups is tolerated, and the thiazoline product has been further utilized for the synthesis of the corresponding β-aminothiol and thiazole from routine hydrolysis and oxidation protocols.
- Alom, Nur-E,Wu, Fan,Li, Wei
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supporting information
p. 930 - 933
(2017/02/26)
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- Visible-Light Photoredox Catalyzed Three-Component Cyclization of 2H-Azirines, Alkynyl Bromides, and Molecular Oxygen to Oxazole Skeleton
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A novel three-component cyclization of 2H-azirines, alkynyl bromides, and molecular oxygen under visible-light photoredox catalysis at room temperature has been developed, which provides a direct approach to a wide range of substituted oxazoles in moderate to good yields.
- Chen, Lili,Li, Hongji,Li, Pinhua,Wang, Lei
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supporting information
p. 3646 - 3649
(2016/08/16)
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- I2-catalyzed synthesis of substituted imidazoles from vinyl azides and benzylamines
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A novel and efficient I2-catalyzed oxidative tandem cyclization of simple vinyl azides and benzylamines has been developed for the synthesis of substituted imidazoles. In this reaction, various substituted groups on vinyl azides and benzylamines proceed smoothly and the desired imidazoles are obtained in moderate to good yields.
- Xiang, Likui,Niu, Yanning,Pang, Xiaobo,Yang, Xiaodong,Yan, Rulong
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supporting information
p. 6598 - 6600
(2015/04/14)
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- Green and Efficient: Iron-Catalyzed Selective Oxidation of Olefins to Carbonyls with O2
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A mild and operationally simple iron-catalyzed protocol for the selective aerobic oxidation of aromatic olefins to carbonyl compounds is described. Catalyzed by a Fe(III) species bearing a pyridine bisimidazoline ligand at 1 atm of O2, α- and β-substituted styrenes were cleaved to afford benzaldehydes and aromatic ketones generally in high yields with excellent chemoselectivity and very good functional group tolerance, including those containing radical-sensitive groups. With α-halo-substituted styrenes, the oxidation took place with concomitant halide migration to afford α-halo acetophenones. Various observations have been made, pointing to a mechanism in which both molecular oxygen and the olefinic substrate coordinate to the iron center, leading to the formation of a dioxetane intermediate, which collapses to give the carbonyl product. (Chemical Equation).
- Gonzalez-De-Castro, Angela,Xiao, Jianliang
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supporting information
p. 8206 - 8218
(2015/07/15)
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- Rh(III)-catalyzed cyclopropanation initiated by C-H activation: Ligand development enables a diastereoselective [2 + 1] annulation of N-enoxyphthalimides and alkenes
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N-Enoxyphthalimides undergo a Rh(III)-catalyzed C-H activation initiated cyclopropanation of electron deficient alkenes. The reaction is proposed to proceed via a directed activation of the olefinic C-H bond followed by two migratory insertions, first across the electron-deficient alkene and then by cyclization back onto the enol moiety. A newly designed isopropylcyclopentadienyl ligand drastically improves yield and diastereoselectivity.
- Piou, Tiffany,Rovis, Tomislav
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supporting information
p. 11292 - 11295
(2014/09/17)
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- SYNTHESE, EIGENSCHAFTEN UND CARBONYL-INSERTIONS-REAKTIONEN VON TETRACARBONYLEISEN(0)-KOMPLEXEN para-SUBSTITUIERTER STYROLE
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The Fe(CO)4 η2-complexes of para-substituted styrenes (substituent=H, CH3, OCH3, Cl, F) can be obtained in good yields.Complexation changes drastically the chemical shifts and coupling constants of the vinyl protons.Reaction of the complexes wi
- Schmidt, Eckhart K.G.,Dogan, Mehmet
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