- Engaging Alkenyl Halides with Alkylsilicates via Photoredox Dual Catalysis
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Single-electron transmetalation via photoredox/nickel dual catalysis provides the opportunity for the construction of Csp3-Csp2 bonds through the transfer of alkyl radicals under very mild reaction conditions. A general procedure for the cross-coupling of primary and secondary (bis-catecholato)alkylsilicates with alkenyl halides is presented. The developed method allows not only alkenyl bromides and iodides but also previously underexplored alkenyl chlorides to be employed. (Chemical Equation Presented).
- Patel, Niki R.,Kelly, Christopher B.,Jouffroy, Matthieu,Molander, Gary A.
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Read Online
- A green hunsdiecker reaction of cinnamic acids
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Tribromo- and trichloroisocyanuric acids react with cinnamic acids in NaOH/H2O/Et2O at room temperature to produce (E)-2-halostyrenes regioselectively in 25-95percent yield. Mechanism studies using Hammett correlations and DFT (density functional theory) calculations have shown that this reaction has as rate determining step the electrophilic addition of chlorine atom to the double bond.
- Sodre?, Leonardo R.,Esteves, Pierre M.,De Mattos, Marcio C. S.
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Read Online
- A green Hunsdiecker reaction: Synthesis of β-bromostyrenes from the reaction of α,β-unsaturated aromatic carboxylic acids with KBr and H2O2 catalysed by Na2MoO4·2H2O in aqueous medium
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Reaction of α,β-unsaturated aromatic carboxylic acids with KBr and H2O2 in the presence of Na2MoO4·2H2O in aqueous medium affords β-bromo alkenes in high yield.
- Sinha,Layek,Mandal,Bhattacharjee
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Read Online
- A mild and efficient method for oxidative halodecarboxylation of α,β-unsaturated aromatic acids using lithium bromide/chloride and ceric ammonium nitrate
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A mild and efficient ecofriendly method for the halodecarboxylation of α,β-unsaturated aromatic acids has been developed by using lithium bromide/chloride and ceric ammonium nitrate in acetonitrile-water at room temperature to afford the vinyl halides in moderate to good yields.
- Roy, Subhas Chandra,Guin, Chandrani,Maiti, Gourhari
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Read Online
- Regio- and stereoselective synthesis of bromoalkenes by homolytic hydrobromination of alkynes with hydrogen bromide
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Homolytic hydrobromination of terminal and internal alkynes with a commercially available solution of hydrogen bromide in acetic acid has been investigated for regio- and stereoselective synthesis of bromoalkenes. Under an aerobic atmosphere at room temperature, the reaction of ethynylarenes with a small excess of HBr efficiently gave (2-bromoethenyl)arenes with good to high E-selectivity. (Alk-1-ynyl)arenes, or internal alkynes bearing both phenyl and alkyl groups at the sp-carbons also underwent the air-initiated hydrobromination to exhibit high Z-selectivity under kinetic conditions using a half equivalent of HBr.
- Kinoshita, Hidenori,Kumaki, Wataru,Miura, Katsukiyo
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- Cyclic Diaryl λ3-Bromanes: A Rapid Access to Molecular Complexity via Cycloaddition Reactions
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Biaryls have widespread applications in organic synthesis. However, sequentially polysubstituted biaryls are underdeveloped due to their challenging preparation. Herein, we report the synthesis of dissymetric 2,3,2′,3′,4-substituted biaryls via pericyclic reactions of cyclic diaryl λ3-bromanes. The functional groups tolerance and atom economy allow access to molecular complexity in a single reaction step. Continuous flow protocol has been designed for the scale-up of the reaction, while postfunctionalizations have been developed taking advantage of the residual Br-atom.
- Lanzi, Matteo,Ali Abdine, Racha Abed,De Abreu, Maxime,Wencel-Delord, Joanna
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supporting information
p. 9047 - 9052
(2021/12/06)
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- Illuminatinganti-hydrozirconation: controlled geometric isomerization of an organometallic species
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A general strategy to enable the formalanti-hydrozirconation of arylacetylenes is reported that mergescis-hydrometallation using the Schwartz Reagent (Cp2ZrHCl) with a subsequent light-mediated geometric isomerization atλ= 400 nm. Mechanistic delineation of thecontra-thermodynamic isomerization step indicates that a minor reaction product functions as an efficientin situgenerated photocatalyst. Coupling of theE-vinyl zirconium species with an alkyne unit generates a conjugated diene: this has been leveraged as a selective energy transfer catalyst to enableE→Zisomerization of an organometallic species. Through anUmpolungmetal-halogen exchange process (Cl, Br, I), synthetically useful vinyl halides can be generated (up toZ?:?E= 90?:?10). This enabling platform provides a strategy to access nucleophilic and electrophilic alkene fragments in both geometric forms from simple arylacetylenes.
- Gilmour, Ryan,Hostmann, Theresa,Nevesely, Tomá?
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p. 10643 - 10648
(2021/08/20)
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- Selective Rhodium-Catalyzed Hydroformylation of Terminal Arylalkynes and Conjugated Enynes to (Poly)enals Enabled by a π-Acceptor Biphosphoramidite Ligand
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The hydroformylation of terminal arylalkynes and enynes offers a straightforward synthetic route to the valuable (poly)enals. However, the hydroformylation of terminal alkynes has remained a long-standing challenge. Herein, an efficient and selective Rh-catalyzed hydroformylation of terminal arylalkynes and conjugated enynes has been achieved by using a new stable biphosphoramidite ligand with strong π-acceptor capacity, which affords various important E-(poly)enals in good yields with excellent chemo- and regioselectivity at low temperatures and low syngas pressures.
- Zhao, Jiangui,Zheng, Xueli,Tao, Shaokun,Zhu, Yuxin,Yi, Jiwei,Tang, Songbai,Li, Ruixiang,Chen, Hua,Fu, Haiyan,Yuan, Maolin
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supporting information
p. 6067 - 6072
(2021/08/16)
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- The hydrodebromination of 1,1-dibromoalkenes via visible light catalysis
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Vinyl bromides are versatile synthetic intermediates and widely applied in organic synthesis and pharmaceuticals. Herein, a hydrodebromination reaction of 1,1-dibromoalkenes was established via visible light catalysis. A variety of structurally different vinyl bromides were obtained in moderate to excellent yields.
- Sun, Wencheng,Teng, Qiaoling,Cheng, Dongping,Li, Xiaonian,Xu, Xiaoliang
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- Method for synthesizing beta-bromostyrene through metal-free catalysis
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The invention discloses a method for synthesizing beta-bromostyrene through metal-free catalysis, and belongs to the technical field of organic chemistry. Substituted styrene 1 is used as a raw material and is reacted in the presence of a bromination reagent, sodium persulfate and dichloroethane, and the beta-bromostyrene compound 2 can be obtained in one step. The method is capable of solving thetechnical problem that in the traditional synthesis method, conversion into alkenyl boron, alkenyl silicon and other intermediates under the catalysis of noble metals and then further halogenation are needed; the defects of expensive reaction reagent, high catalytic cost, complex operation, incapability of large-scale preparation and the like in the traditional preparation method are avoided; byadopting the method, a series of beta-bromostyrene compounds can be obtained, and the method has a potential application prospect.
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Paragraph 0040-0042
(2020/02/06)
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- Facile Synthesis of β-Bromostyrenes by Direct Bromination of Styrenes with N -Bromosuccinimide and Sodium Persulfate
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A new, direct, efficient, and transition-metal-free method is reported for the synthesis of β-bromostyrenes from styrenes by using N -bromosuccinimide as the brominating reagent and sodium persulfate (Na 2S 2O 8) as the oxidant. This convenient and concise reaction is practical, operationally simple, and can be adapted for large-scale syntheses.
- Chen, Xuenian,Gao, Yan,Jing, Yi,Ma, Yan-Na,Zhao, Qianyi
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supporting information
(2020/09/09)
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- Electrochemical intramolecular C-H/N-H functionalization for the synthesis of isoxazolidine-fused isoquinolin-1(2: H)-ones
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A general and practical protocol for the construction of isoxazolidine-fused isoquinolin-1(2H)-ones has been described by electrochemical-oxidation-induced intramolecular annulation via amidyl radicals. In an undivided cell, isoquinolinones could be easily generated from various available amides bearing CONHOR groups under metal-free, additive-free and external oxidant-free conditions. Moreover, this transformation proceeded smoothly by using cheap 95% ethanol as the green solvent and could be extended to the gram scale.
- Zhang, Lin-Bao,Geng, Rui-Sen,Wang, Zi-Chen,Ren, Guang-Yi,Wen, Li-Rong,Li, Ming
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- 2-arylvinyl-cyclic amine derivative, preparation method and applications thereof
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The invention belongs to the technical field of medicines, and discloses a 2-arylvinyl-cyclic amine derivative, a preparation method and applications thereof. The biological activity test results showthat the 2-arylvinyl-cyclic amine derivative has selective M1 receptor antagonism activity. The compounds can be used as a pharmaceutically active ingredient in treatment of diseases mediated by a M1receptor. According to the method, the 2-arylvinyl-cyclic amine derivative can be obtained by reacting -diarylalkylene bromide and cyclic tertiary amine, and the simple and efficient method for synthesizing the 2-aryl vinyl-cyclic amine derivative is provided.
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Paragraph 0044-0048; 0051-0055
(2020/04/29)
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- Dual nickel- and photoredox-catalyzed reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides
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A novel reductive cross-coupling of aryl vinyl halides and unactivated tertiary alkyl bromides has been realized via photoredox/nickel dual catalysis to produce vinyl arene derivatives bearing all-carbon quaternary centers with excellent E-selectivity. A stoichiometric metal reductant could be avoided by employing commercially available N,N,N′,N′-tetramethylethylenediamine (TMEDA) as the terminal reductant.
- Yu, Weijie,Chen, Long,Tao, Jiasi,Wang, Tao,Fu, Junkai
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supporting information
p. 5918 - 5921
(2019/05/27)
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- Construction of Phenanthrenes and Chrysenes from β-Bromovinylarenes via Aryne Diels-Alder Reaction/Aromatization
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A highly efficient transition-metal-free general method for the synthesis of polycyclic aromatic hydrocarbons like phenanthrenes and chrysenes (and tetraphene) from β-bromovinylarenes and arynes has been developed. The reactions proceed via an aryne Diels-Alder (ADA) reaction, followed by a facile aromatization. This is the first report on direct construction of chrysenes (and tetraphene) using the ADA approach. Unlike the literature method which is limited to only 9/10-substituted derivatives, this method gives access to a wide variety of functionalized phenanthrenes.
- Singh, Vikram,Verma, Ram Subhawan,Khatana, Anil K.,Tiwari, Bhoopendra
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p. 14161 - 14167
(2019/10/28)
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- Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides
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This study explores a Pd-catalyzed decarboxylative Heck-type Csp3-Csp2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.
- Chang, Chi-Hao,Chou, Chih-Ming
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supporting information
p. 1949 - 1952
(2018/04/16)
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- Direct Cross-Coupling of Allylic C(sp3)?H Bonds with Aryl- and Vinylbromides by Combined Nickel and Visible-Light Catalysis
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An efficient protocol for the direct allylic C(sp3)?H bond activation of unactivated tri- and tetrasubstituted alkenes and their functionalization with aryl- and vinylbromides by nickel and visible-light photocatalysis has been developed. The method allows C(sp2)?C(sp3) formation under mild reaction conditions with good functional-group tolerance and excellent regioselectivity.
- Huang, Long,Rueping, Magnus
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p. 10333 - 10337
(2018/07/31)
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- A Facile Access to trans -3-Styryl-4-hydrazinocyclopentenes via Palladium-Catalyzed Ring Opening of Diazanorbornenes with (Z)-β-Bromostyrenes/2,3-Dibromohydrocinnamic Acids
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trans -3-Styryl-4-hydrazinocyclopentenes have been synthesized via palladium-catalyzed desymmetrization of diazanorbornenes with (Z)-β-bromostyrenes. The reaction also works well with (Z)-β-bromostyrenes generated in situ from 2,3-dibromohydrocinnamic acids. The synthesized hydrazinocyclopentenes provide an easy route towards synthetic intermediates of many scaffolds of biological potential.
- Saranya,Chand, S. Sarath,Gopalan, Greeshma,Jijitha,Radhakrishnan
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p. 184 - 192
(2017/10/13)
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- Palladium-Catalyzed Domino Reaction for Stereoselective Synthesis of Multisubstituted Olefins: Construction of Blue Luminogens
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The first Pd-catalyzed multicomponent reaction of aryl iodides, alkenyl bromides, and strained alkenes has been developed, which allowed us to synthesize a variety of multisubsituted olefins in yields of 45-96% with excellent stereoselectivity. The configuration of the product was controlled by the configuration of the alkenyl bromides. Moreover, this practical methodology employing readily available substrates was found to be tolerant to a wide range of functional groups. Fifty six examples of highly stereoselective tri- or tetrasubstituted olefins have been successfully synthesized via this methodology. Most of the synthesized tetrasubstituted olefins are good aggregation-induced emission (AIE) luminogens.
- Hao, Tao-Tao,Liang, Hao-Ran,Ou-Yang, Ying-Han,Yin, Chang-Zhen,Zheng, Xue-Li,Yuan, Mao-Lin,Li, Rui-Xiang,Fu, Hai-Yan,Chen, Hua
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p. 4441 - 4454
(2018/04/26)
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- cis-β-Bromostyrene derivatives from cinnamic acids via a tandem substitutive bromination-decarboxylation sequence
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cis-β-Bromostyrene derivatives were synthesized stereospecifically from cinnamic acids through β-lactone intermediates. The synthetic sequence did not require the purification of the β-lactone intermediates although they were found to be stable and readily purified in most cases.
- Tang, Khanh G.,Kent, Greggory T.,Erden, Ihsan,Wu, Weiming
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p. 3894 - 3896
(2017/09/15)
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- A stereoselective synthesis of (E)- or (Z)-β-arylvinyl halides via a borylative coupling/halodeborylation protocol
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A new stereoselective method for the synthesis of (E)-β-arylvinyl iodides and (E)- or (Z)-β-arylvinyl bromides from styrenes and vinyl boronates on the basis of a one-pot procedure via borylative coupling/halodeborylation is reported. Depending on the halogenating agent as well as the mode of the halodeborylation reaction, (E) or (Z) isomers are selectively formed.
- Szyling, Jakub,Franczyk, Adrian,Pawlu?, Piotr,Marciniec, Bogdan,Walkowiak, J?drzej
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p. 3207 - 3215
(2017/04/21)
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- Nickel-Catalyzed Reductive Cross-Coupling of Vinyl Bromides with Unactivated Alkyl Halides
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The use of pyridine as the sole ligand for the reductive vinylation of unactivated secondary alkyl halides under Ni-catalyzed conditions has been developed. Both alkyl- and aryl-substituted vinyl bromides are suitable, in which alkyl-decorated α-alkenyl bromides resulted in the α-products in good results.
- Gu, Jun,Qiu, Canbin,Lu, Wenbin,Qian, Qun,Lin, Kunhua,Gong, Hegui
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supporting information
p. 1867 - 1873
(2017/04/06)
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- Decarboxylative bromination of α,β-unsaturated carboxylic acids via an anodic oxidation
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A novel bromination of α,β-unsaturated carboxylic acids was developed via a decarboxylation by virtue of a direct anodic electro-oxidation. In this method, ammonium bromide was employed as a bromine source and the reaction features transition-metal-free, short time, and no additional supporting electrolyte.
- Bi, Mei-Xiang,Qian, Peng,Wang, Yu-Kang,Zha, Zheng-Gen,Wang, Zhi-Yong
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p. 1159 - 1162
(2017/06/19)
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- Stereoselective Synthesis of Vinyl Iodides through Copper(I)-Catalyzed Finkelstein-Type Halide-Exchange Reaction
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An efficient method for the stereoselective synthesis of vinyl iodides is described. The reactions of vinyl bromides with potassium iodide proceed smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding vinyl iodides stereospecifically and in satisfactory to excellent yields.
- Feng, Xiujuan,Zhang, Haixia,Lu, Wenbo,Yamamoto, Yoshinori,Almansour, Abdulrahman I.,Arumugam, Natarajan,Kumar, Raju Suresh,Bao, Ming
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supporting information
p. 2727 - 2732
(2017/06/13)
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- Palladium-Catalyzed Two-Component Domino Coupling Reaction of (Z)-β-Bromostyrenes with Norbornenes: Synthesis of 1,5-Enynes
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Polyfunctional molecules, 1,5-enynes, have been achieved via a palladium(0)-catalyzed domino coupling reaction of (Z)-β-bromostyrenes with norbornenes in the presence of cesium carbonate and N,N-dimethylformamide. The process involves a double Heck-type procedure, two-fold C(sp2) H activation and formation of two carbon-carbon bonds. There are possibilities of diversified transformation for the domino coupling of (Z)-β-bromostyrenes with norbornenes, the procedure is successfully driven to 1,5-enynes via accurate adjustment of the reaction conditions. (Figure presented.) .
- Mao, Jiangang,Li, Huifang,Wen, Herui,Li, Min,Fan, Xiaolin,Bao, Weiliang
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supporting information
p. 1873 - 1879
(2016/07/06)
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- Preparation of Vinyl Arenes by Nickel-Catalyzed Reductive Coupling of Aryl Halides with Vinyl Bromides
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This work emphasizes the synthesis of substituted vinyl arenes by reductive coupling of aryl halides with vinyl bromides under mild and easy-to-operate nickel-catalyzed reaction conditions. A broad range of aryl halides, including heteroaromatics, and vinyl bromides were employed to yielding products in moderate to excellent yields with high functional-group tolerance. The nickel-catalytic system displays good chemoselectivity between the two C(sp2)-halide coupling partners, thus demonstrating a mechanistic pathway distinct from other stepwise protocols.
- Liu, Jiandong,Ren, Qinghua,Zhang, Xinghua,Gong, Hegui
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supporting information
p. 15544 - 15548
(2016/12/09)
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- A General Copper-Catalyzed Vinylic Halogen Exchange Reaction
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An efficient and general system for the halogen exchange reaction in alkenyl halides has been developed. Upon reaction with catalytic amounts of copper iodide and trans-N,N′-dimethylcyclohexane-1,2-diamine in the presence of tetramethylammonium chloride or bromide, a wide range of easily accessible alkenyl iodides can be smoothly transformed to their far less available chlorinated and brominated derivatives in excellent yields and with full retention of the double bond geometry. This reaction also enables the chlorination of bromoalkenes and could be extended to the use of gem-dibromoalkenes.
- Nitelet, Antoine,Evano, Gwilherm
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supporting information
p. 1904 - 1907
(2016/05/19)
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- Development of a general copper-catalyzed vinylic Finkelstein reaction—application to the synthesis of the C1–C9 fragment of laingolide B
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An efficient and broadly applicable procedure for the copper-catalyzed vinylic Finkelstein reaction is reported. Using a simple, readily available and cheap catalytic system, a broad range of alkenyl iodides and bromides can be smoothly converted to their lower homologues with high yields and full retention of the double bond geometry. Key features of this vinylic Finkelstein reaction are its broad applicability, enabling the conversion of readily available alkenyl iodides to their less available brominated and chlorinated counterparts, and the mild reaction conditions compatible with a range of highly functionalized substrates. The potential of this vinylic halogen exchange reaction in total synthesis and medicinal chemistry was demonstrated by its successful use for the synthesis of the C1–C9 fragment of laingolide B and for the late-stage modification of drug-like molecules. The extension of this halogen exchange to the acetylenic and allenic Finkelstein reactions is also reported.
- Nitelet, Antoine,Jouvin, Kévin,Evano, Gwilherm
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p. 5972 - 5987
(2016/09/16)
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- Ultrasonically Assisted Decarboxylative Bromination of α,β-Unsaturated Carboxylic Acids under Vilsmeier-Haack Conditions
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An efficient method for decarboxylative bromination of cinnamic acids (α,β-unsaturated carboxylic acids or 3-arylpropenoic acids) was achieved under relatively mild conditions using Vilsmeier-Haack reagent and KBr in acetonitrile media. Vilsmeier-Haack reagent is prepared by using 1:1 ratio of oxychloride (SOCl2 or POCl3) and DMF under chilled condition. Ultrasonically assisted reactions underwent smoothly with highly significant rate enhancements and afforded bromostyrenes as products in very good yields even though the reactions were too sluggish.
- Kumar, M. Satish,Rajanna,Venkanna,Venkateswarlu,Sudhakar Chary
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p. 642 - 646
(2015/12/26)
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- Pd-Catalyzed C(sp3)-C(sp2) cross-coupling of Y(CH2SiMe3)3(THF)2 with vinyl bromides and triflates
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Pd-Catalyzed C(sp3)-C(sp2) cross-coupling of Y(CH2SiMe3)3(THF)2 with vinyl bromides and triflates has been developed for efficient synthesis of various allyltrimethylsilanes. The cross-coupling reaction was conducted at room temperature with low catalyst loading of either Pd(PPh3)4 or Pd(PPh3)2Cl2, and exhibited high efficiency and a broad substrate scope. In combination with the cross-coupling by the Lewis-acid catalyzed Hosomi-Sakurai reaction, a novel three-component one-pot cascade reaction was then accomplished to deliver homoallylic alcohols and ethers with high regioselectivity and diastereoselectivity. The three-component reaction defined the yttrium complex as a novel one-carbon synthon, which could either trigger bifunctionalization of alkenes or link two electrophiles and would find applications in organic synthesis.
- Cai, Guilong,Zhou, Zhibing,Wu, Wenchao,Yao, Bo,Zhang, Shaowen,Li, Xiaofang
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supporting information
p. 8702 - 8706
(2016/10/03)
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- Tellurium-promoted stereoselective hydrodebromination of 1,1-dibromoalkenes: Synthesis of (: E)-bromoalkenes
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We describe herein an efficient and simple method for the stereoselective hydrodebromination of 1,1-dibromoalkenes by using a catalytic amount of the nucleophilic species of tellurium, generated in situ by the reaction of elemental tellurium with NaBH4. By this methodology, (E)-bromoalkenes were obtained in moderate to excellent yields under mild reaction conditions, without the use of transition metals or base. Furthermore, a high stereoselectivity for the (E)-isomer was observed when 1,1-dibromoarylalkenes were used, thus indicating a promising alternative for future applications in organic synthesis.
- Perin, Gelson,Barcellos, Angelita M.,Peglow, Thiago J.,Nobre, Patrick C.,Cargnelutti, Roberta,Lenard?o, Eder J.,Marini, Francesca,Santi, Claudio
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p. 103657 - 103661
(2016/11/13)
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- Expedient Iodocyclization Approach Toward Polysubstituted 3H-Benzo[e]indoles
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A facile and expedient iodocyclization of 4-(2-prop-1-ynylphenyl)-1H-pyrroles towards the synthesis of polysubstituted 3H-benzo[e]indoles is reported. The transformation was optimized and the best results were obtained by using iodine (1.2 equiv,) in dichloromethane, and potassium carbonate as base. The starting 1,2,3,4-tetrasubstituted pyrroles were efficiently obtained by means of a nickel(II) chloride-promoted four-component (nitromethane, amine, 2-alkynylbenzaldehyde and ethyl acetoacetate) reaction. Further functionalization of the resulting 5-iodoheterocycles was also explored.
- Martins, Guilherme M.,Zeni, Gilson,Back, Davi F.,Kaufman, Teodoro S.,Silveira, Claudio C.
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supporting information
p. 3255 - 3261
(2015/11/03)
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- Palladium(0)-Catalyzed Methylcyclopropanation of Norbornenes with Vinyl Bromides and Mechanism Study
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An unusual methylcyclopropanation from [2 + 1] cycloadditions of vinyl bromides to norbornenes catalyzed by Pd(OAc)2/PPh3 in the presence of CH3ONa and CH3OH has been established. A methylcyclopropane subunit was installed by a 3-fold domino procedure involving a key protonation course. Preliminary deuterium-labeling studies revealed that the proton came from methyl of CH3OH and also exposed an additional hydrogen/deuterium exchange process. These two proton-concerned reactions were fully chemoselective.
- Mao, Jiangang,Xie, Hujun,Bao, Weiliang
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supporting information
p. 3678 - 3681
(2015/08/18)
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- Pd-Catalyzed Difluoromethylation of Vinyl Bromides, Triflates, Tosylates, and Nonaflates
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Pd-catalyzed difluoromethylation of di-, tri- or tetra-substituted vinyl bromides, triflates, tosylates and nonaflates under mild conditions is described. The reaction tolerates a wide range of functional groups, such as bromide, chloride, fluoride, ester, amine, nitrile, and protected carbonyl, thus providing a general route for the preparation of difluoromethylated alkenes. Vinyl fantasy: Pd-catalyzed difluoromethylation of di-, tri-, or tetra-substituted vinyl bromides, triflates, tosylates, and nonaflates under mild conditions is described. The reaction tolerates a wide range of functional groups, such as bromide, chloride, fluoride, ester, amine, nitrile, and protected carbonyl, thus providing a general route for the preparation of difluoromethylated alkenes.
- Chang, Dalu,Gu, Yang,Shen, Qilong
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supporting information
p. 6074 - 6078
(2015/04/14)
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- Palladium(0)-catalyzed methylenecyclopropanation of norbornenes with vinyl bromides
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Highly strained methylenecyclopropane derivatives have been achieved via a novel and efficient Pd(0)-catalyzed domino reaction. The formal [2 + 1] cycloaddition reaction of vinyl bromides to norbornenes involves a Heck-type coupling and a C(sp2)-H bond activation.
- Mao, Jiangang,Bao, Weiliang
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supporting information
p. 2646 - 2649
(2014/06/09)
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- Palladium-catalyzed [2+1+1] annulation of norbornenes with (z)-bromostyrenes: Synthesis of bismethylenecyclobutanes via twofold C(sp2)-H bond activation
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The first Pd-catalyzed intermolecular [2+1+1] annulation reaction of (Z)-bromostyrene derivatives and norbornenes has been realized. Bismethylenecyclobutane derivatives were obtained with high yields. The domino coupling reaction involves a double Heck-type coupling process, twofold C(sp2)-H bond activation and formation of three carbon-carbon bonds.
- Mao, Jiangang,Bao, Weiliang
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supporting information
p. 15726 - 15729
(2015/01/08)
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- Nickel-catalyzed asymmetric reductive cross-coupling between vinyl and benzyl electrophiles
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A Ni-catalyzed asymmetric reductive cross-coupling between vinyl bromides and benzyl chlorides has been developed. This method provides direct access to enantioenriched products bearing aryl-substituted tertiary allylic stereogenic centers from simple, stable starting materials. A broad substrate scope is achieved under mild reaction conditions that preclude the pregeneration of organometallic reagents and the regioselectivity issues commonly associated with asymmetric allylic arylation.
- Cherney, Alan H.,Reisman, Sarah E.
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supporting information
p. 14365 - 14368
(2014/12/11)
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- H-β-zeolite catalyzed synthesis of β-bromostyrenes from styrene bromohydrins
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Synthesis of β-bromostyrenes from styrene bromohydrins using H-β-zeolite as catalyst under moderate conditions is reported. The catalyst could be regenerated and reused up to three consecutive cycles.
- Pappula, Venkatanarayana,Donthiri, Ramachandra Reddy,Darapaneni, Chandra Mohan,Subbarayappa, Adimurthy
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supporting information
p. 1793 - 1795
(2014/03/21)
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- Stereoselective synthesis of (Z)-β-arylvinyl bromides from anti-2,3-dibromo-3-arylpropanoic acids
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A novel method for the stereoselective synthesis of (Z)-β-arylvinyl bromides in excellent yields by debrominative decarboxylation of anti-2,3-dibromo-3-arylpropanoic acids using NaN3 was developed. This facile transformation was achieved under room temperature for 1-2 h.
- Xv, Wenjing,Zhang, Wensheng,Zhang, Fei,Kuang, Chunxiang
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p. 115 - 117
(2014/03/21)
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- Transition-metal free synthesis of diaryl vinyl selenides: A simple synthetic approach with high selectivity
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A simple, highly efficient synthetic protocol is developed for the synthesis of unsymmetrical diaryl vinyl selenides from diaryldiselenide and β-bromo styrene under transition-metal free conditions in N,N′-dimethyl propylene urea and 130 °C to afford high yields and excellent selectivities. This method provides a new strategy to fabricate a wide variety of important substituted molecular skeletons and an alternative to conventionally used metal salts, additives, and ligands.
- Mohan, Balaji,Hwang, Sori,Woo, Hyunje,Park, Kang Hyun
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supporting information
p. 2699 - 2702
(2014/04/17)
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- Nickel(II)-magnesium-catalyzed cross-coupling of 1,1-dibromo-1-alkenes with diphenylphosphine oxide: One-pot synthesis of (E)-1-alkenylphosphine oxides or bisphosphine oxides
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A novel nickel(II)-magnesium-mediated cross-coupling of diphenylphosphine oxide with a variety of 1,1-dibromo-1-alkenes has been developed, which provides a powerful and general methodology for the stereoselective synthesis of various (E)-1-alkenylphosphine oxides or bisphosphine oxides, with operational simplicity of the procedure, good to high yields and broad substrate applicability. Mechanistic studies reveal that the reaction might involve a Hirao reduction, cross-coupling and Michael addition. Copyright
- Liu, Liu,Wang, Yulei,Zeng, Zhiping,Xu, Pengxiang,Gao, Yuxing,Yin, Yingwu,Zhao, Yufen
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p. 659 - 666
(2013/04/10)
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- Formation of quaternary stereogenic centers by copper-catalyzed asymmetric conjugate addition reactions of alkenylaluminums to trisubstituted enones
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Alkenylaluminums undergo asymmetric copper-catalyzed conjugate addition (ACA) to β-substituted enones allowing the formation of stereogenic all-carbon quaternary centers. Phosphinamine-copper complexes proved to be particularly active and selective compared with phosphoramidite ligands. After extensive optimization, high enantioselectivities (up to 96 % ee) were obtained for the addition of alkenylalanes to β-substituted enones. Two strategies for the generation of the requisite alkenylaluminums were explored allowing for the introduction of aryl- and alkyl-substituted alkenyl nucleophiles. Moreover, alkyl-substituted phosphinamine (SimplePhos) ligands were identified for the first time as highly efficient ligands for the Cu-catalyzed ACA. Chiral synthesis made easy: The copper-catalyzed conjugate addition of alkenylaluminum reagents to 3-substituted cyclic enones allows for the formation of all-carbon chiral quaternary centers (see scheme; CuTC=copper(I) thiophene-2-carboxylate). Chiral phosphinamine (SimplePhos) ligands were found to be highly efficient for this transformation.
- Mueller, Daniel,Alexakis, Alexandre
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p. 15226 - 15239
(2013/11/06)
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- On the Origin of E/Z Selectivity in the Modified Julia Olefination - Importance of the Elimination Step
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The mechanism and origin of high E selectivity in the modified Julia olefination of aromatic aldehydes have been explored by computational and experimental means. Reversibility of addition and hence selectivity of the formation of sulfinate 5 is very variable and depends on the nature of the sulfone substrate. However, in all cases, elimination occurs through a concerted antiperiplanar and synperiplanar mechanism for sulfinates anti-5 and syn-5, respectively. Both syn and anti diastereomeric pathways thus lead preferentially to the (E)-alkene. Copyright
- Robiette, Raphael,Pospisil, Jiri
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supporting information
p. 836 - 840
(2013/03/29)
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- Decarboxylative bromination of cinnamic acids by 2-iodoxybenzoic acid with tetrabutylammonium bromide
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The decarboxylative bromination of cinnamic acids using the hypervalent iodine reagent 2-iodoxybenzoic acid with tetrabutylammonium bromide is described, providing good to excellent yields of bromostyrenes. Bromostyrenes are useful coupling components in a wide range of transition metal-catalysed coupling reactions.
- Han, Jianlei,Wei, Yuping
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experimental part
p. 247 - 248
(2012/09/22)
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- C-1 alkynylation of N-methyltetrahydroisoquinolines through CDC: A direct access to phenethylisoquinoline alkaloids
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Direct cross-coupling between N-methyltetrahydroisoquinolines and alkynes using CuI-DEAD is presented. It affords the regioselective C-1-alkynylated products in good yield. This regio-selectivity is in contrast to the results reported earlier in the reaction of N,N-dimethylbenzyl amine where the N-methyl alkynylated product was formed exclusively or predominantly. The C-1-substituted propargylic isoquinolines were easily reduced to phenethylisoquinolines with Pd/C. This reaction sequence provides a short route to synthesize methopholine, homolaudanosine and other phenethylisoquinoline alkaloids. Georg Thieme Verlag Stuttgart · New York.
- Singh, Kamal Nain,Singh, Paramjit,Kaur, Amarjit,Singh, Pushpinder
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p. 760 - 764
(2012/07/02)
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- Regioselective copper(I)-catalyzed C-H hydroxylation/C-S coupling: Expedient construction of 2-(styrylthio)phenols
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Regioselective copper(I)-catalyzed C-H hydroxylation/C-S coupling of aryl thiols with vinyl halides was developed. Starting from substituted aryl thiols and vinyl halides, various 2-(styrylthio)phenol derivatives were efficiently prepared. The application of the synthetic methodology to generate the bioactive organic intermediate was also exemplified.
- Xu, Run-Sheng,Yue, Lei,Pan, Yuan-Jiang
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experimental part
p. 5046 - 5052
(2012/08/07)
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- A novel method for bromodecarboxylation of α,β-unsaturated carboxylic acids using catalytic sodium nitrite
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A first novel synthetic utility of catalytic sodium nitrite in combination with aqueous HBr, for bromo decarboxylation of α,β-unsaturated carboxylic acid is described. α,β-Unsaturated carboxylic acid compounds successfully converted into corresponding bromo compounds. The advantages of this protocol are shorter reaction time and moderate to good yields.
- Telvekar, Vikas N.,Takale, Balaram S.
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experimental part
p. 2394 - 2396
(2011/05/09)
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- Cu and Au nanocomposites in catalytic olefination reaction
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Metal-vapor synthesis-prepared Cu, Ag, Au and bimetallic Au-Cu (optimal) nanocomposites catalyse olefination of hydrazones with polyhalomethanes.
- Nenajdenko, Valentine G.,Vasil'Kov, Alexander Yu.,Goldberg, Aleksey A.,Muzalevskiy, Vasiliy M.,Naumkin, Alexander V.,Podshibikhin, Vladislav L.,Shastin, Aleksey V.,Balenkova, Elizabeth S.
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scheme or table
p. 200 - 202
(2011/03/20)
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- Copper oxide nanoparticles catalyzed vinylation of imidazoles with vinyl halides under ligand-free conditions
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Recyclable copper oxide nanoparticles catalyzed most efficient and straightforward protocol for the vinylation of imidazoles with vinyl halides under ligand-free conditions. Utilizing this protocol various imidazoles were cross-coupled with different substituted vinyl halides to get the corresponding products in excellent yields with the retention configuration.
- Prakash Reddy,Vijay Kumar,Rama Rao
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supporting information; experimental part
p. 3181 - 3185
(2010/08/05)
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- Novel system for decarboxylative bromination of α,β-unsaturated carboxylic acids with diacetoxyiodobenzene
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A simple and mild method for the conversion of varieties of α,β-unsaturated carboxylic acids to the corresponding bromoalkenes using diacetoxyiodobenzene (IBD) in combination with tetraethyl-ammonium bromide (TEAB) at room temperature is discussed. Advantages of this system are short reaction time, easy work up and gave good to excellent yields.
- Fursule, Ravindra Abhykumar,Patil, Pravin Onkar,Shewale, Bharti Devaji,Kosalge, Satish Bhaskar,Deshmukh, Prashant Krishnarao,Patil, Dilip Ashok
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experimental part
p. 1243 - 1245
(2010/08/06)
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- New one-pot synthesis of (E)-β-aryl vinyl halides from styrenes
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A new, efficient protocol for the highly stereoselective one-pot synthesis of (E)-β-aryl vinyl iodides and (£)-β-aryl vinyl bromides from styrenes based on sequential ruthenium-catalyzed silylative coupling-N-halosuccinimide-mediated halodesilylation reactions is reported.
- Pawluc, Piotr,Hreczycho, Grzegorz,Szudkowska, Justyna,Kubicki, Maciej,Marciniec, Bogdan
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supporting information; experimental part
p. 3390 - 3393
(2009/12/01)
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- A novel system for decarboxylative bromination
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A simple and mild method for decarboxylative bromination of α,β-unsaturated carboxylic acids has been developed using diphosphorus tetraiodide in combination with tetraethylammonium bromide (TEAB) at room temperature. High yields of the corresponding bromoalkenes were obtained.
- Telvekar, Vikas N.,Chettiar, Somsundaram N.
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p. 4529 - 4532
(2008/02/03)
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