- Synthesis and characterization of cyclobutenedione-bithiophene π-conjugated polymers: Acetal-protecting strategy for Kumada-Tamao-Corriu coupling polymerization between aryl bromide and Grignard reagents
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Cyclobutenedione is an aromatic ring that exhibits strong electron-withdrawing properties but is susceptible to undesired reactions with nucleophiles. Herein, Kumada-Tamao-Corriu coupling polymerization of a cyclobutenedione monomer whose carbonyl groups
- Ohishi, Tomoyuki,Sone, Takuma,Oda, Kohei,Yokoyama, Akihiro
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- A new method for the regio and stereoselective hydrocarboxylation of alkynes using NaHFe(CO)4/CH2Cl2 system
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The reagent generated in situ in THF using NaHFe(CO)4 and CH2Cl2 was used for the regio and stereoselective hydrocarboxylation of terminal and internal alkynes to obtain α,β-unsaturated carboxylic acid derivatives.
- Periasamy, Mariappan,Radhakrishnan, Ukkiramapandian,Rameshkumar, Chellappan,Brunet, Jean-Jacques
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- New Convenient One-Pot Methods of Conversion of Alkynes to Cyclobutenediones or α,β-Unsaturated Carboxylic Acids Using Novel Reactive Iron Carbonyl Reagents
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Reactions of NaHFe(CO)4/RX or [HFe3(CO)11]- reagents with alkynes lead to the formation of the corresponding α,β-unsaturated carboxylic acids and/or the cyclobutenediones. The reagent generated in situ using the NaHFe(CO)4/CH3I combination in THF, on reaction with alkynes followed by CuCl2·2H2O oxidation, gives the corresponding cyclobutenediones (27-42%) and α,β-unsaturated carboxylic acids (10-22%), whereas the reagent generated using CH2Cl2 in place of CH3I leads to α,β-unsaturated carboxylic acids (37-60%) and their derivatives (35-55%) at 25°C. The same reagent system in the presence of acetic acid (4 equiv) yields the corresponding cyclobutenedione (33%). The reaction using Me3SiCl gives the corresponding α,β-unsaturated carboxylic acids (45-54%) at 25°C and the corresponding cyclobutenediones (51-63%) at 60°C. Interestingly, the reaction of the [HFe3(CO)11]- species generated using Fe(CO)5/NaBH4/CH3COOH, with alkynes at 25°C, followed by CuCl2·2H2O oxidation gives the corresponding cyclobutenediones (60-73%). The possible intermediates and pathways for the formation of α,β-unsaturated carboxylic acids and cyclobutenediones are discussed.
- Periasamy, Mariappan,Rameshkumar, Chellappan,Radhakrishnan, Ukkiramapandian,Brunet, Jean-Jacques
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- Double carbonylation of alkynes using NaHFe(CO)4
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The reagent generated in situ using NaHFe(CO)4 and MeI in THF, on reaction with alkynes followed by CuCl2 oxidation, gives the corresponding cyclobutenediones in moderate yields (27-42%) in addition to the corresponding α,β-unsaturated carboxylic acids (10-22%).
- Periasamy, Mariappan,Radhakrishnan, Ukkiramapandian,Brunet, Jean-Jacques,Chauvin, Remi,El Zaizi, Abdel Wahed
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- Silver catalyzed decarbonylative [3 + 2] cycloaddition of cyclobutenediones and formamides
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As an important moiety in natural products, N,O-acetal has attracted wide attention in the past few years. An efficient method to construct N,O-acetal has been developed. Using silver catalyst, cyclobutenediones were smoothly converted to the corresponding γ-aminobutenolides in the presence of formamides, in which cyclobutenediones likely proceed with a key decarbonylative [3 + 2] cycloaddition process. In this way, a series of products with varied substituents were isolated in moderate yield and fully characterized.
- Ali, Sajjad,Gao, Jinming,Liu, Zhigang,Wang, Pengcheng,Wang, Zhengshen,Yu, Ruirui,Zheng, Huaiji
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- Reactive iron carbonyl reagents via reaction of metal alkoxides with Fe(CO)5 or Fe2(CO)9: Synthesis of cyclobutenediones via double carbonylation of alkynes
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Alkoxy bases such as t-BuOK react with Fe(CO)5 to give reactive iron carbonyl intermediates that in turn react with alkynes at 70 °C in THF to give 1,2-cyclobutenediones in 70-93% yields after CuCl2· 2H2O oxidation. A novel 1,2-diacyloxyferrole derivative was isolated in the reaction of diphenylacetylene with Fe(CO)5/t-BuOK in the presence of acetyl chloride in contrast to the formation of a 1,4-diacyloxyferrole complex formed in the reaction using Fe(CO) 5/Me3NO. The Fe2(CO)9/t-BuOK reagent system also converts the alkynes to corresponding cyclobutenediones in 63-90% yields under similar reaction conditions.
- Beesu, Mallesh,Periasamy, Mariappan
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experimental part
p. 543 - 549
(2011/04/16)
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- A simple and convenient method for the synthesis of cyclobutenediones from alkynes using new Fe(CO)5/NaH/MeI reagent system
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Iron carbonyl complexes prepared in situ using the Fe(CO)5/NaH/MeI reagent combination and alkynes at 25 °C give the corresponding cyclobutenediones in 50-65% yields after CuCl2 · 2H2O oxidation.
- Periasamy, Mariappan,Beesu, Mallesh,Shyam Raj
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p. 2843 - 2846
(2008/12/21)
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- Pd-catalyzed, Cu(I)-mediated cross-couplings of bisarylthiocyclobutenediones with boronic acids and organostannanes
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(Chemical Equation Presented) Bisarylthiocyclobutenedione 7 reacted smoothly with a variety of both organostannanes and (hetero)arylboronic acids in the presence of a catalytic amount of Pd and a stoichiometric amount of CuTC to produce symmetrical disubstituted cyclobutenediones in yields that range from 37 to 94% (18 examples).
- Aguilar-Aguilar, Angelica,Liebeskind, Lanny S.,Pena-Cabrera, Eduardo
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p. 8539 - 8542
(2008/03/11)
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- Amine induced carbonylation of alkynes to cyclobutenediones using Fe3(CO)12
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Iron carbonyl species, prepared in situ in THF using Fe3(CO)12, react with alkynes at 25°C, in the presence of certain amines, to give the corresponding cyclobutenediones in moderate to good yields (25-61%) after CuCl2·2H
- Rameshkumar, Chellappan,Periasamy, Mariappan
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p. 2719 - 2722
(2007/10/03)
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- Ladderane-like motifs: Solid state architecture of trans-1,2-diphenyl-1- cyclobutene-3,4-diol dinitrate
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C2-Symmetric trans-1,2-diphenyl-1-cyclobutene-3,4-diol dinitrate defines a novel ladderane-like motif in the solid state through a network of C-H...O interactions between aromatic C-H donor and a weak acceptor like the nitrate ester group.
- Mehta, Goverdhan,Uma
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p. 1154 - 1158
(2007/10/03)
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- Generation of 1,2-bisketenes from cyclobutene-1,2-diones by flash photolysis and ring closure kinetics
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The interconversion of cyclobutene-1,2-diones (1) and 1,2-bisketenes (RC-C-O)2 has been surveyed for different combinations of substituents R = H, Me, t-Bu, Ph, Me3Si, CN, Cl, Br, R1O, alkynyl, and PhS. The bisketenes 2 have been generated by flash photolysis, and the kinetics of their conversion to 1 have been studied by time-resolved infrared and ultraviolet spectroscopy. The rate constants of the ring closure of 2 are correlated by the ketene stabilization parameters (SE) and with calculated barriers. The rate constant of ring closure of the di-tert-butyl bisketene 2g to cyclobutenedione 1g is only 40 times smaller than for the dimethyl analogue, showing a rather modest steric barrier. The quinoketene 2s has a fast rate of ring closure, but not as fast as anticipated on the basis of calculated geometric and thermodynamic factors. A lag in the attainment of aromatic stabilization in the transition structure for ring closure is a possible cause of this diminished reactivity.
- Allen, Annette D.,Colomvakos, Jim D.,Diederich, Fran?ois,Egle, Ian,Hao, Xiaokuai,Liu, Ronghua,Lusztyk, Janusz,Ma, Jihai,McAllister, Michael A.,Rubin, Yves,Sung, Kuangsen,Tidwell, Thomas T.,Wagner, Brian D.
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p. 12125 - 12130
(2007/10/03)
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- Facile addition of dichloroketene to acetylenes mediated by zinc and ultrasound
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The addition of dichloroketene, generated from trichloroacetyl chloride, zinc dust and ultrasound, to terminal and internal acetylenes is reported. This procedure is a more convenient alternative to Zn-Cu couple.
- Parker,Rizzo
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p. 2781 - 2789
(2007/10/02)
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