- Polysubstituted ethylene compound as well as preparation method and application thereof
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The invention discloses a polysubstituted ethylene compound as well as a preparation method and application thereof. The invention particularly discloses a preparation method of a polysubstituted ethylene compound as shown in a formula III, which comprises the following step: in an organic solvent, carrying out reaction as shown in the specification on a compound as shown in a formula I and a compound as shown in a formula II in the presence of a palladium catalyst, a phosphine ligand and alkali to obtain the polysubstituted ethylene compound as shown in the formula III. The preparation methodcan be suitable for various types of substrates, and the configuration of double bonds is controllable.
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Paragraph 0125-0129; 0230-0234
(2020/12/30)
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- Oxiranyl remote anions from epoxy cinnamates and their application towards the synthesis of α,β-epoxy-γ-butyrolactones
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A series of α,β-epoxy-γ-butyrolactones were synthesized in moderate yields via oxiranyl remote anions derived from epoxy cinnamate esters. The key synthetic step involved deprotonation of the β-position of α,β-epoxy cinnamate derivatives where the generated β-anion was stabilized by remote chelation from an ester group. The substitution reaction of the anion with a variety of ketones, followed by cyclization, readily furnished the desired substituted α,β-epoxy-γ-butyrolactones.
- Sermmai, Patpanat,Ruangsupapichat, Nopporn,Thongpanchang, Tienthong
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supporting information
(2020/11/19)
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- Following palladium catalyzed methoxycarbonylation by hyperpolarized NMR spectroscopy: A: para hydrogen based investigation
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Pd(OTf)2(bcope) is shown to react in methanol solution with diphenylacetylene, carbon monoxide and hydrogen to produce the methoxy-carbonylation product methyl 2,3 diphenyl acrylate alongside cis- and trans-stilbene. In situ NMR studies harnessing the parahydrogen induced polarization effect reveal substantially enhanced 1H NMR signals in both protic and aprotic solvents for a series of reaction intermediates that play a direct role in this homogeneous transformation. Exchange spectroscopy (EXSY) measurements reveal that the corresponding CO adducts are less reactive than their methanol counterparts.
- Guan, Dexin,Jonathan Holmes,López-Serrano, Joaquín,Duckett, Simon B.
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p. 2101 - 2109
(2017/07/15)
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- New Pd(II) binuclear complexes as effective catalysts in oxidative-heck reaction using arylboronic acid derivatives
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A series of new binuclear Pd(II) complexes based on chelating diimines and bridging diphosphine or diimine ligands have been synthesized and characterized successfully. The formula of the new complexes are [Pd2(mbyp) 2(DPA)2](PF6)4 (1), [Pd 2(mbyp)2(DPE)2] (PF6)4 (2), [Pd2(mbyp)2(4,4-byp)2] (PF 6)4 (3), [Pd2(mbyp)2(t-pye) 2] (PF6)4 (4) [mbyp= 4,4-dimethyl-2,2- bipyridine, DPA= 1,2-bis(diphenylphosphino)acetylene, DPE= 1,2- bis(diphenylphosphino)ethylene, 4,4-byp= 4,4-bipyridine, and t-ype= trans 1,2-bis(4-pyridyl)ethylene)]. The catalytic activities of the new complexes have been investigated in the coupling of arylboronic acid derivatives to various olefins. Results obtained showed interesting catalytic activities and chemoselectivities for the new complexes in the coupling reactions to produce the conjugate addition and heck coupling products under free base or oxidant conditions.
- Suleiman, Rami,Shakil Hussain,Fettouhi, Mohammed,El Ali, Bassam
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scheme or table
p. 850 - 856
(2012/09/22)
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- Synthesis of dineophyltin dihydride and stereoselective hydrostannation of alkynes and (E)-trisubstituted alkenes
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This paper reports the synthesis of dineophyltin dihydride (3) following two procedures. The four steps synthesis starting from benzyl chloride and Sn was shown to be more convenient than the two step direct alkylation of SnCl 4. The study of the free radical hydrostannation of mono- and disubstituted acetylenes with hydride 3 shows that they are stereoselective and that the stereoisomers obtained in higher proportion are stable and easily separated by column chromatography. Some preliminary studies on the chemical reactivity of the new divinylsubstituted dineophyltin compounds in Stille reactions are also informed. Radical hydrostannatation of (E)-trisubstituted ethylenes with 3 did not succeed probably due to steric factors. The preparation of dineophyltin bromohydride (27) is also reported. Radical addition of 27 to methyl (E)-2,3-disubstituted propenoates leads to mixtures of the corresponding erythro and threo adducts in diastereomeric excesses (d.e.) in the range of 74-90%.
- Zú?iga, Adriana E.,Fidelibus, Pablo M.,Mandolesi, Sandra D.,Podestá, Julio C.
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experimental part
p. 1547 - 1555
(2011/06/17)
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- The non-metathetic role of Grubbs' carbene complexes: From hydrogen-free reduction of α,β-unsaturated alkenes to solid-supported sequential cross-metathesis/reduction
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An efficient and high-yielding "hydrogen-free" reduction of α,β-unsaturated alkenes was carried out employing Grubbs' catalyst in a non-metathetic role and Et3SiH. Conditions were optimized under microwave irradiation. Application to the solid-phase organic synthesis allows a facile construction of sp3-sp3 carbon bonds through a sequential cross metathesis/olefin reduction.
- Poeylaut-Palena, Andres A.,Testero, Sebastian A.,Mata, Ernesto G.
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supporting information; experimental part
p. 1565 - 1567
(2011/03/20)
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- Rhodium catalyzed reaction of internal alkynes with organoborons under CO atmosphere: a product tunable reaction
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Alkynes react with organoborons under a CO atmosphere in the presence of a rhodium(I) catalyst to afford mainly 5-aryl-2(5H)-furanones, α,β-unsaturated ketones, and indanones. The product selectivity can be tuned by modifying the reaction conditions.
- Artok, Levent,Ku?, Melih,Aksin-Artok, ?zge,Dege, Fatma Nurcan,?zkilin?, Fatma Yelda
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scheme or table
p. 9125 - 9133
(2010/01/16)
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- Synthesis of α,β-unsaturated ketones by rhodium-catalyzed carbonylative arylation of internal alkynes with arylboronic acids
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The Rh-catalyzed reaction of arylboronic acids with internal alkynes under a CO atmosphere in the presence of an acid additive afforded α,β-unsaturated ketones as the major products. Hydroacylation of internal alkynes, except in the case of diaryl acetylenes, proceeded in syn fashion, yielding the E-configured isomer. A mixture of E- and Z-isomers was obtained with diphenyl acetylene. Reactions were also highly regioselective for various nonsymmetric alkynes.
- Ku?, Melih,Artok, ?zge Aksin,Ziyanak, Firat,Artok, Levent
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experimental part
p. 2587 - 2592
(2009/04/16)
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- Stereoselective synthesis of Z-α-aryl-α,β-unsaturated esters
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An efficient method for the stereoselective synthesis of (Z)-α-arylacrylates is described. Treatment of α-hydroxyesters with triflic anhydride and pyridine at 0 °C followed by warming to room temperature afforded the corresponding (Z)-α-aryl-α,β- unsatura
- Mani, Neelakandha S.,Mapes, Christopher M.,Wu, Jiejun,Deng, Xiaohu,Jones, Todd K.
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p. 5039 - 5042
(2007/10/03)
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- Mechanism of β-silyl diacyl peroxide decomposition: A mild and stereoselective synthesis of β-silyl esters
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A novel method for the formation of β-silyl esters is presented. Mechanistic studies were carried out on the formation and decomposition of β-silyl diacyl peroxides, showing that the decomposition pathway involves an ionic mechanism that is influenced by the presence of the β-silyl moiety. These studies exclude a free radical decomposition pathway as evidenced by the absence of chemically induced dynamic nuclear polarization (CIDNP) during the reaction and a strong correlation of the resulting regioisomeric product distribution to σ+. This reaction allows for the formation of β-silyl esters in 45-50% isolated yield with predictable regioselectivity and good to excellent diastereoselectivity. Studies demonstrate that ester products which are formed at benzylic centers have the erythro configuration, whereas ester products formed at alkyl centers have the threo configuration.
- Masterson, Douglas S.,Porter, Ned A.
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p. 3693 - 3699
(2007/10/03)
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- ETUDE DE LA REACTION CHLOROCARBENE-ACETALS DE CETENES. I. SYNTHESE D'ESTERS α,β-ETHYLENIQUES.
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The reaction of chloro, chloromethyl and chlorophenyl carbenoids with ketene alkylsilylacetals has been studied.Excellent yields of cyclopropanation were observed and the unstable chlorocyclopropanone acetals formed were thermally rearranged in high yield into α-substituted α,β-ethylenic esters.This new method for the synthesis of unsaturated esters appeared complementary of the known-ones.
- Slougui, N.,Rousseau, G.
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p. 2643 - 2652
(2007/10/02)
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- OLEFIN SYNTHESIS VIA FRAGMENTATION OF HINDERED ESTER HALIDES
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Hindered methyl esters possessing allylic or benzylic bromine substituents undergo smooth dealkylative decarboxylation to afford olefinic derivatives.
- Belletire, J. L.,Walley, D. R.
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p. 1475 - 1476
(2007/10/02)
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