- Stereocontrolled synthesis of carbon-carbon double bond locked analogues of strobilurins which are characterized by a trans-1,2-disubstituted cyclopropane ring
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The racemic forms of four new carbon-carbon double bond locked analogues of strobilurins, which are characterized by a trans-1,2-disubstituted cyclopropane ring, have been synthesized according to a strategy which involves palladium-catalyzed cross-coupli
- Rossi,Carpita,Ribecai,Mannina
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- Asymmetric Halocyclizations of 2-Vinylbenzyl Alcohols with Chiral FLPs
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By the use of a chiral frustrated Lewis pair (FLP) consisting of a chiral-diene-derived borane and tBu3P as the catalyst, an asymmetric halocyclization of 2-vinylbenzyl alcohols with NBS or NIS was successfully realized. A variety of optically active 1,3-dihydroisobenofuran derivatives were obtained in high yields with up to 87% ee and could be conveniently converted to other useful chiral compounds.
- Han, Caifang,Feng, Xiangqing,Du, Haifeng
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supporting information
p. 7325 - 7329
(2021/10/01)
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- Enantioselective synthesis of 1-aminoindene derivativesviaasymmetric Br?nsted acid catalysis
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We describe a catalytic asymmetric iminium ion cyclization reaction of simple 2-alkenylbenzaldimines using a BINOL-derived chiralN-triflyl phosphoramide. The corresponding 1-aminoindenes and tetracyclic 1-aminoindanes are formed in good yields and high enantioselectivities. Further, the chemical utility of the obtained enantiopure 1-aminoindene is demonstrated for the asymmetric synthesis of (S)-rasagiline.
- Ding, Du,Jiang, Hua-Jie,Wang, Tao,Wu, Xiang,Zhang, Ying,Zhao, Li-Ping
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supporting information
p. 9680 - 9683
(2021/09/30)
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- Asymmetric Synthesis and Application of Chiral Spirosilabiindanes
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Reported here is the development of a class of chiral spirosilabiindane scaffolds by Rh-catalyzed asymmetric double hydrosilation, for the first time. Enantiopure SPSiOL (spirosilabiindane diol), a new type of chiral building block for the preparation of various chiral ligands and catalysts, was readily prepared on greater than 10 gram scale using this protocol. The potential of this new spirosilabiindane scaffold in asymmetric catalysis was preliminarily demonstrated by development of the corresponding monodentate phosphoramidite ligands (SPSiPhos), which were used in both a Rh-catalyzed hydrogenation and a Pd-catalyzed intramolecular carboamination.
- Chang, Xin,Chen, Hong-Chao,Li, Chuan-Ying,Ma, Pei-Long,Wang, Peng
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p. 8937 - 8940
(2020/04/30)
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- Preparation method of silicon spiro compound (by machine translation)
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The invention discloses a preparation method of a silicon spiro compound. The invention provides a preparation method of a silicon spiro compound as shown in a formula II, which comprises the following steps: in a solvent, a compound represented by the formula III is subjected to cyclization reaction under the presence of a monovalent rhodium catalyst and a phosphine ligand to obtain the silicon spiro compound as shown in the formula II. The preparation method of the silicon spiro compound can be simple. , The establishment of the silicon spiro compound is realized conveniently and efficiently. (by machine translation)
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Paragraph 0234-0236
(2020/06/17)
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- Cu/Ni-Catalyzed Cyanomethylation of Alkenes with Acetonitrile for the Synthesis of β,γ-Unsaturated Nitriles
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We have developed a protocol for the Cu/Ni-catalyzed cyanomethylation of alkenes with acetonitrile for the synthesis of β,γ-unsaturated nitriles. This is the first example of a direct coupling of the alkene sp2 C - H bond and the acetonitrile sp3 C - H bond for the preparation of β,γ-unsaturated nitriles. Acetonitrile, an inexpensive and stable solvent, is demonstrated to be a useful cyanomethyl source. The combination of copper and nickel catalysts resulted in a high reaction efficiency.
- Jian, Hong,Shen, Zengming,Zhang, Saisai
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p. 6143 - 6150
(2020/05/22)
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- The Different Faces of [Ru(bpy)3Cl2] and fac[Ir(ppy)3] Photocatalysts: Redox Potential Controlled Synthesis of Sulfonylated Fluorenes and Pyrroloindoles from Unactivated Olefins and Sulfonyl Chlorides
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A cascade alkene sulfonylation that simultaneously forges C-S and C-C bonds is a highly efficient and powerful approach for directly accessing structurally diverse sulfonylated compounds in a single operation. The reaction was enabled by visible-light-mediated regioselective radical addition of sulfonyl chlorides to 2-arylstyrenes using fac[Ir(ppy)3] as a photocatalyst, demonstrating its unique role in a photocascade process to execute atom transfer radical addition (ATRA) followed by photocyclization. A new class of sulfonyl-substituted fluorenes and pyrroloindoles, which are useful in the field of photoelectronic materials and medicinal chemistry, was produced in excellent yields by this photocascade reaction. In contrast, the cyclization was interrupted when using the [Ru(bpy)3Cl2] catalyst having lower reduction potential, leading only to the formation of a C-S bond and the production of acyclic sulfonylated 2-arylstyrenes under identical reaction conditions. The synthetic utility of the present room-temperature photocatalysis is enhanced by the broad availability of bench-stable sulfonyl chlorides and unactivated olefins, thereby providing a cost-effective and broad-scope protocol.
- Pagire, Santosh K.,Kumagai, Naoya,Shibasaki, Masakatsu
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supporting information
p. 7853 - 7858
(2020/10/12)
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- Reactivity of Carbenes in Aqueous Nanomicelles Containing Palladium Nanoparticles
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Palladium nanoparticles ligated with inexpensive triphenylphosphine and amphiphile PS-750-M are suitable for exploring the reactivity of carbenes in aqueous nanomicelles. Nanocatalyst is highly selective for metal-carbene migratory insertion, and micelle
- Duong, Uyen T.,Gade, Amol B.,Plummer, Scott,Gallou, Fabrice,Handa, Sachin
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p. 10963 - 10970
(2019/11/13)
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- Pd-Catalyzed Enantioselective Ring Opening/Cross-Coupling and Cyclopropanation of Cyclobutanones
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A palladium-catalyzed enantioselective sequential ring-opening/cross-coupling of cyclobutanones is disclosed that provides chiral indanones bearing C3-quaternary stereocenters. The reaction process involves palladium-catalyzed nucleophilic addition of cyc
- Cao, Jian,Chen, Ling,Sun, Feng-Na,Sun, Yu-Li,Jiang, Ke-Zhi,Yang, Ke-Fang,Xu, Zheng,Xu, Li-Wen
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supporting information
p. 897 - 901
(2019/01/04)
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- Synthesis of Substituted Naphthalenes by 1,4-Palladium Migration Involved Annulation with Internal Alkynes
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The palladium catalyzed annulation of 1-bromo-2-vinylbenzene derivatives with internal alkynes was realized for the efficient synthesis of substituted naphthalenes. A controllable aryl to vinylic 1,4-palladium migration process is the key for success.
- Wei, Dong,Hu, Tian-Jiao,Feng, Chen-Guo,Lin, Guo-Qiang
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p. 743 - 748
(2018/07/25)
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- Au-catalyzed biaryl coupling to generate 5- to 9-membered rings: Turnover-limiting reductive elimination versus π-complexation
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The intramolecular gold-catalyzed arylation of arenes by aryl-trimethylsilanes has been investigated from both mechanistic and preparative aspects. The reaction generates 5- to 9-membered rings, and of the 44 examples studied, 10 include a heteroatom (N, O). Tethering of the arene to the arylsilane provides not only a tool to probe the impact of the conformational flexibility of Ar-Au-Ar intermediates, via systematic modulation of the length of aryl-aryl linkage, but also the ability to arylate neutral and electron-poor arenes-substrates that do not react at all in the intermolecular process. Rendering the arylation intramolecular also results in phenomenologically simpler reaction kinetics, and overall these features have facilitated a detailed study of linear free energy relationships, kinetic isotope effects, and the first quantitative experimental data on the effects of aryl electron demand and conformational freedom on the rate of reductive elimination from diaryl-gold(III) species. The turnover-limiting step for the formation of a series of fluorene derivatives is sensitive to the reactivity of the arene and changes from reductive elimination to π-complexation for arenes bearing strongly electron-withdrawing substituents (σ > 0.43). Reductive elimination is accelerated by electron-donating substituents (ρ = -2.0) on one or both rings, with the individual σ-values being additive in nature. Longer and more flexible tethers between the two aryl rings result in faster reductive elimination from Ar-Au(X)-Ar and lead to the π-complexation of the arene by Ar-AuX2 becoming the turnover-limiting step.
- Corrie, Tom J. A.,Ball, Liam T.,Russell, Christopher A.,Lloyd-Jones, Guy C.
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supporting information
p. 245 - 254
(2017/05/29)
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- Rhodium(II)- or Copper(I)-Catalyzed Formal Intramolecular Carbene Insertion into Vinylic C(sp2)?H Bonds: Access to Substituted 1H-Indenes
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A rhodium(II)- or copper(I)-catalyzed formal intramolecular carbene insertion into vinylic C(sp2)?H bonds is reported herein. This method provides straightforward access to 1H-indenes with high efficiency and excellent functional-group compatibility. Mechanistically, the reaction is proposed to involve the following sequence: metal carbene formation, intramolecular nucleophilic addition of the double bond to the electron-deficient carbene carbon atom, dearomatization, and finally a 1,5-H shift.
- Zhou, Qi,Li, Shichao,Zhang, Yan,Wang, Jianbo
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supporting information
p. 16013 - 16017
(2017/11/27)
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- Intramolecular Crossed [2+2] Photocycloaddition through Visible Light-Induced Energy Transfer
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Herein, we present the intramolecular [2+2] cycloadditions of dienones promoted through sensitization, using a polypyridyl iridium(III) catalyst, to form bridged cyclobutanes. In contrast to previous examples of straight [2+2] cycloadditions, these efficient crossed additions were achieved under irradiation with visible light. The reactions delivered desired bridged benzobicycloheptanone products with excellent regioselectivity in high yields (up to 96%). This process is superior to previous syntheses of benzobicyclo[3.1.1]heptanones, which are readily converted to B-norbenzomorphan analogues of biological significance. Electrochemical, computational, and spectroscopic studies substantiated the mechanism of triplet energy transfer and explained the unusual regiocontrol.
- Zhao, Jiannan,Brosmer, Jonathan L.,Tang, Qingxuan,Yang, Zhongyue,Houk,Diaconescu, Paula L.,Kwon, Ohyun
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supporting information
p. 9807 - 9810
(2017/08/03)
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- Borylation of Olefin C-H Bond via Aryl to Vinyl Palladium 1,4-Migration
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The aryl to vinyl palladium 1,4-migration was realized for the first time. The generated alkenyl palladium species was trapped by diboron reagents under Miyaura borylation conditions, providing a new method to synthesize β,β-disubstituted vinylboronates. The excellent regioselectivity and broad substrate scope were observed for this novel transformation.
- Hu, Tian-Jiao,Zhang, Ge,Chen, Ya-Heng,Feng, Chen-Guo,Lin, Guo-Qiang
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p. 2897 - 2900
(2016/03/19)
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- Alkene Dioxygenation with Malonoyl Peroxides: Synthesis of γ-Lactones, Isobenzofuranones, and Tetrahydrofurans
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Treatment of homoallylic alcohols or carboxylic acids with malonoyl peroxide 1 provides a stereoselective method for the preparation of tetrahydrofurans, γ-lactones, and isobenzofuranones in 44-82% yield and up to 27:1 trans selectivity. Application of this simple and effective heterocyclization in the synthesis of the antidepressant citalopram is also described.
- Alamillo-Ferrer, Carla,Karabourniotis-Sotti, Marianna,Kennedy, Alan R.,Campbell, Matthew,Tomkinson, Nicholas C. O.
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supporting information
p. 3102 - 3105
(2016/07/13)
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- Cleavage of C-C and C-Si σ-bonds and their intramolecular exchange
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C-C and C-Si σ-bonds are cleaved to undergo bond exchange when substrates equipped with cyclobutanone and silacyclobutane moieties are treated with a palladium(0) catalyst. The skeletal exchange results in construction of silabicyclo[5.2.1]decanes in a diastereoselective manner.
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
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supporting information
p. 5912 - 5915
(2014/05/20)
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- Intramolecular σ-bond metathesis between carbon-carbon and silicon-silicon bonds
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An intramolecular σ-bond metathesis between carbon-carbon and silicon-silicon bonds took place on treatment of a disilane tethered to a cyclobutanone with a palladium(0) catalyst, furnishing a silaindane skeleton as well as an acylsilane functionality at
- Ishida, Naoki,Ikemoto, Wataru,Murakami, Masahiro
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p. 3230 - 3232
(2012/09/08)
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- Chiral sulfoxide-olefin ligands: Completely switchable stereoselectivity in rhodium-catalyzed asymmetric conjugate additions
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Have it both ways: A novel class of chiral sulfoxide-olefin ligands was synthesized from a single chiral source. These ligands were evaluated in rhodium-catalyzed 1,4-additions of arylboronic acids to electron-deficient olefins, and remarkable olefin-directed reversal of stereoselectivity (up to >99 ee, R isomer; 98 ee, S isomer) was observed when the reversal ligand pair L1 (branched olefin) and L2 (linear olefin) were utilized (see scheme). Copyright
- Chen, Guihua,Gui, Jiangyang,Li, Liangchun,Liao, Jian
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supporting information; experimental part
p. 7681 - 7685
(2011/10/17)
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- Pd-Catalyzed intramolecular oxyalkynylation of alkenes with hypervalent iodine
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(Figure presented) The first example of intramolecular oxyalkynylation of nonactivated alkenes using oxidative Pd chemistry is reported. Both phenol and aromatic or aliphatic acid derivatives could be used under operator-friendly conditions (room temperature, technical solvents, under air). The discovery of the superiority of benzlodoxolone-derlved hypervalent iodine reagent 3d as an alkyne transfer reagent further expands the rapidly increasing utility of hypervalent iodine reagents in catalysis and is expected to have important implications for other similar processes.
- Nicolal, Stefano,Erard, Stephane,Gonzalez, Davinla Fernandez,Waser, Jerome
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supporting information; experimental part
p. 384 - 387
(2010/03/04)
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- Enantioselective C-C bond cleavage creating chiral quaternary carbon centers
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A chiral all-carbon benzylic quaternary carbon center is created by the asymmetric intramolecular addition/ring-opening reaction of a boryl-substituted cyclobutanone, which involves enantioselective β-carbon elimination from a symmetrical rhodium cyclobutanolate. The asymmetric reaction was successfully applied to a synthesis of sesquiterpene, (-)-α-herbertenol.
- Matsuda, Takanori,Shigeno, Masanori,Makino, Masaomi,Murakami, Masahiro
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p. 3379 - 3381
(2007/10/03)
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- Discovery and synthesis of novel phosphine-based ligands for aryl aminations
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Three families of ligands were prepared for use in Pd-catalyzed aryl aminations and possibly other Pd-catalyzed reactions. The first series is derived from diarylsulfones, the second from trityl imidazole, and the third from 2-bromobenzophenone. While these ligands were not very general in terms of substrate scope, they do work fairly well under certain specific conditions. Additionally, the preparation of these ligands is amenable to bulk synthesis.
- Singer, Robert A.,Tom, Norma J.,Frost, Heather N.,Simon, Wendy M.
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p. 4715 - 4718
(2007/10/03)
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- Highly asymmetric dihydroxylation of 1-aryl-1'-pyridyl alkenes
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The asymmetric dihydroxylation of 1-aryl-1'-pyridyl alkenes afforded the diols in high yield and excellent enantioselectivity. (C) 2000 Published by Elsevier Science Ltd.
- Wang, Xin,Zak, Mark,Maddess, Mathew,O'Shea, Paul,Tillyer, Richard,Grabowski,Reider, Paul J.
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p. 4865 - 4869
(2007/10/03)
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- SYNTHESIS AND ELECTROPHILIC REACTIONS OF A CONFORMATIONALLY RIGID CYCLOPROPYLCARBINYL CATION. AN UNUSUAL SYNTHESIS OF SUBSTITUTED BENZAZULENES.
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A tropylium-substituted cyclopropane has been prepared which is rigidly held in the "bisected" conformation.Its electrophilic reactions are also investigated.
- Jason, Mark E.
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p. 1635 - 1638
(2007/10/02)
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