- Crossed Regio- and Enantioselective Iron-Catalyzed [4+2]-Cycloadditions of Unactivated Dienes
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The cyclohexene motif is ubiquitous in nature and specialty chemicals. A straightforward selective access to chiral cyclohexenes from unactivated dienes and dienophiles is not feasible by classical Diels–Alder reaction and constitutes an unsolved syntheti
- Braconi, Elena,Cramer, Nicolai
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supporting information
(2021/12/22)
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- Photoinduced copper-catalyzed dual decarboxylative coupling of α,β-unsaturated carboxylic acids with redox-active esters
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The first photoinduced copper-catalyzed dual decarboxylative cross-coupling of α,β-unsaturated carboxylic acids and redox-active esters has been developed. This reaction enabled C(sp2)–C(sp3) bond formation, which afforded a variety of synthetically valuable alkene derivatives. Many α,β-unsaturated carboxylic acids and redox-active ester derivatives were tolerant to this reaction. The reaction also tolerated many common functional groups.
- Lu, Xiao-Yu,Gao, Ang,Liu, Qi-Le,Xia, Ze-Jie
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supporting information
(2021/06/15)
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- Vinyl Sulfonium Salts as the Radical Acceptor for Metal-Free Decarboxylative Alkenylation
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Vinyl sulfonium salts typically act as an electrophilic Michael acceptor, thus initiating many tandem cyclization reactions. Herein, we disclosed the novel reactivity of vinyl sulfonium salts as a radical acceptor. Using redox-active ester as an alkyl rad
- Zhang, Yu-Lan,Yang, Lei,Wu, Jie,Zhu, Chunyin,Wang, Peng
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supporting information
p. 7768 - 7772
(2020/10/09)
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- Iron-Catalyzed Vinylic C?H Alkylation with Alkyl Peroxides
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A variety of alkyl peresters and alkyl diacyl peroxides, which are readily accessible from carboxylic acids, are utilized as general primary, secondary, and tertiary alkylating reagents for iron-catalyzed vinylic C?H alkylation of vinyl arenes, dienes, and 1,3-enynes. This transformation affords olefinic products in up to 98 % yield with high E/Z values. A broad range of functionalities, including carboxyl, boronic acid, methoxy, ester, amino, and halides, are tolerated. This protocol provides a facile approach to some olefins that are difficult to access, and hence, offers an alternative to existing systems. The synthetic utility of this method is demonstrated by late-stage functionalization of selected natural-product derivatives.
- Ge, Liang,Jian, Wujun,Zhou, Huan,Chen, Shaowei,Ye, Changqing,Yu, Fei,Qian, Bo,Li, Yajun,Bao, Hongli
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supporting information
p. 2522 - 2528
(2018/08/01)
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- Palladium-tetraphosphine complex catalysed heck reaction of vinyl bromides with alkenes: A powerful access to conjugated dienes
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A wide variety of 1,3-dienes have been prepared by the Heck vinylation of vinyl bromides using [Pd(η3-C3H5)Cl] 2/cis,cis,cis-1,2,3,4-tetrakis[(diphenylphosphino)methyl] cyclopentane (Tedicyp) as the catalyst precursor. Both α- and β-substituted vinyl bromides undergo the Heck reaction with functionalised alkenes such as acrylates, enones, styrenes or a vinyl sulfone, and also with nonfunctionalised alkenes such as dec-1-ene, leading stereoselectively, in most cases, to the corresponding E- or E,E-1,3-dienes in good yields. Furthermore, this catalyst can be used at low loading for several reactions. Georg Thieme Verlag Stuttgart.
- Lemhadri, Mhamed,Battace, Ahmed,Berthiol, Florian,Zair, Touriya,Doucet, Henri,Santelli, Maurice
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p. 1142 - 1152
(2008/12/22)
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- A simple radical addition - Elimination route to geometrically pure (E)-alkene and chromanone derivatives via β-nitrostyrene
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Various geometrically pure (E)-β-alkyl-styrenes have been synthesized by the radical NO2 substitution of alkyl moieties generated via hydrogen abstraction followed by decarbonylation from aliphatic aldehydes. These reactions, which involve a high chemical selectivity and regioselectivity constitute a new route to (E)-β-alkylstyrenes. Both aliphatic and aromatic aldehydes can be used in this novel reaction. When 2-allyloxybenzaldehyde was used, the benzoyl radical added directly to the double bond without decarbonylation to give the 3-cinnamylchroman-4-one. This unique difference between aliphatic and aromatic aldehydes represents a simple route for the synthesis of biologically important chromanones.
- Jang, Yeong-Jiunn,Yan, Ming-Chung,Lin, Yung-Feng,Yao, Ching-Fa
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p. 3961 - 3963
(2007/10/03)
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- Heck reaction of vinyl bromides with alkenes in the presence of a tetraphosphine/palladium catalyst
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Through the use of [PdCl(C3H5)]2- cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of vinyl bromides undergo Heck reaction with a wide variety of alkenes leading selectively to the corresponding 1,3-dienes in good yields. Furthermore, it can be used at low loading even for reactions of sterically hindered vinyl bromides.
- Berthiol, Florian,Doucet, Henri,Santelli, Maurice
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p. 841 - 844
(2007/10/03)
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- On the Twofold Heck Reaction of 4-Vinylcyclohexene and p-Dihalobenzenes
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The palladium-catalyzed reaction of iodobenzene, p-haloiodobenzenes (p-C6H4IX'; X' = F, Cl, Br, I) and p-dibromobenzene with 4-vinylcyclohexene (Heck arylation reaction of olefins) was investigated with Pd(OAc)2/PR3/Et3N (R = phenyl, o-tolyl) as a classic
- Lorenz, Peter,Becher, Diana,Steinborn, Dirk,Poetsch, Eike,Akermark, Bjoern
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p. 375 - 378
(2007/10/02)
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- Isomerisation de dienes-1,5 fonctionnalises par le fer pentacarbonyle
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A series of various, functionnalized 4-vinylcyclohexene derivatives, substituted with electron-withdrawing or -donating groups on the exocyclic double bond, have been isomerized by pentacarbonyliron, under thermodynamic control with heating, into a mixture of conjugated cyclohexadiene tricarbonyliron complexes, of which the 2-substituted derivative is the predominant.When ferrous chloride is used as the co-catalyst, the isomerisation proceeds under kinetic control to give the 1-substituted cyclohexadienetricarbonyliron complex as the major derivative.Reaction mechanisms, have been proposed for these isomerisation processes, which provide a new selective route to such derivatives.The formation of η4-1,4-cyclohexadienetricarbonyl complexes as intermediates has been excluded, and it is shown that the thermal isomerisation proceeds via η2-complexes that are formed by successive 1,3-hydrogen shifts.
- Rodriguez, J.,Brun, P.,Waegell, B.
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p. 343 - 370
(2007/10/02)
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- CARBOPALLADATION DES ALKYLIDENECYCLOPROPANES-I; CAPTURE INTERMOLECULAIRE DE L'ORGANOPALLADIQUE INTERMEDIAIRE
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The reaction of methylenecyclopropane and 1-cyclopropylidene pentane with iodobenzene or 2-bromopropene and a delocalized anion (issued from malonate or from a β-sulfonyl ester) in the presence of catalytic amounts of a palladium (0) complex leads to conj
- Fournet, Guy,Balme, Genevieve,Gore, Jacques
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p. 5809 - 5820
(2007/10/02)
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