- Synthesis of Silylated Cyclobutanone and Cyclobutene Derivatives Involving 1,4-Addition of Zinc-Based Silicon Nucleophiles
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A copper-catalyzed conjugate silylation of various cyclobutenone derivatives with Me2PhSiZnCl ? 2LiCl or (Me2PhSi)2Zn ? xLiCl (x≤4) to generate β-silylated cyclobutanones is reported. Trapping the intermediate enolate with ClP(O)(OPh)2 affords silylated enol phosphates that can be further engaged in Kumada cross-coupling reactions to yield silylated cyclobutene derivatives.
- Cui, Ming,Oestreich, Martin
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supporting information
p. 16103 - 16106
(2021/10/12)
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- -Cycloaddition Reaction of Sulfilimines with Cyclobutenones: Access to Benzazepinones
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A catalyst-free [4+3]-cycloaddition reaction of N-aryl sulfilimines with cyclobutenones is described, which provides a straightforward protocol for synthesizing 1,5-dihydro-2H-benzo[b]azepin-2-ones under mild reaction conditions. This reaction features a
- Xie, Xiaozhou,Sun, Jiangtao
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p. 8921 - 8925
(2021/11/20)
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- Enantioselective Synthesis of 4-Hydroxy-dihydrocoumarins via Catalytic Ring Opening/Cycloaddition of Cyclobutenones
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A highly diastereo- and enantioselective ring-opening/cycloaddition reaction of cyclobutenones with 2-hydroxyacetophenones or salicylaldehyde was achieved by employing a chiral N,N′-dioxide-scandium(III) complex as the catalyst. It provided various 3-phen
- Zhang, Hang,Luo, Yao,Li, Dawei,Yao, Qian,Dong, Shunxi,Liu, Xiaohua,Feng, Xiaoming
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p. 2388 - 2392
(2019/03/29)
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- Rhodium(i)-catalysed intermolecular alkyne insertion into (2-pyridylmethylene)cyclobutenes
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Cyclobutenes with 2-pyridylmethylene groups at the 3 position underwent an intermolecular alkyne insertion reaction in the presence of a rhodium(i) catalyst at 170 °C to afford substituted benzenes. Among the different 2-pyridylmethylene groups examined, 3-methyl-2-pyridyl derivatives showed superior activity and readily coupled with various alkynes, including sterically demanding, heteroaromatic and terminal alkynes.
- Matsuda, Takanori,Matsumoto, Takeshi
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p. 5023 - 5027
(2016/06/14)
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- Regiodivergent cyclobutanone cleavage: Switching selectivity with different Lewis acids
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The exploitation of strain release in small rings as driving force to enable complex transformations is a powerful synthetic tool. Among them, cyclobutanones are particularly versatile substrates that can be elaborated in a wide variety of structurally diverse building blocks. Herein, Lewis acid catalyzed rearrangement reactions are presented that provide selective access to two structurally distinct polycyclic scaffolds, that is, indenylacetic acid derivatives and benzoxabicyclo[3.2.1]octan-3-ones. The choice of the Lewis acid fully controls the reaction pathway and the regioselectivity of the cyclobutanone C-C bond cleavage site.
- Souillart, Laetitia,Cramer, Nicolai
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p. 1863 - 1867
(2015/01/30)
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- Rh(II)-catalyzed [2,3]-sigmatropic rearrangement of sulfur ylides derived from N-tosylhydrazones and sulfides
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In this paper, Rh2(OAc)4-catalyzed [2,3]-sigmatropic rearrangement of sulfur ylides derived from N-tosylhydrazones and sulfides is reported. A series of tosylhydrazones derived from aldehydes were successfully used for [2,3]-sigmatropic rearrangement by reaction with either allylic phenyl sulfides or propargyl phenyl sulfides. The reaction conditions were optimized and afforded the products in moderate to good yields. In addition, a novel and convenient approach for the synthesis of cyclobutenones and cyclopropanes has been developed through direct oxidation of the rearrangement products.
- Li, Yuye,Huang, Zhongxing,Wu, Xinhu,Xu, Peng-Fei,Jin, Jing,Zhang, Yan,Wang, Jianbo
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experimental part
p. 5234 - 5240
(2012/08/07)
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- Efficient approach to 1,2-diazepines via formal diazomethylene insertion into the C-C bond of cyclobutenones
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Efficient monocyclic 1,2-diazepine formation via a tandem electrocyclization reaction of cyclobutenones with lithiodiazoacetate is demonstrated. The reaction proceeds through an oxy anion-accelerated 4π-ring opening of cyclobutene followed by an 8π-ring closure of the resultant oxy anion-substituted diazo-diene under mild conditions to furnish a 1,2-diazepine via formal diazomethylene insertion into the C-C bond of cyclobutenone.
- Sugimoto, Kenji,Hayashi, Rie,Nemoto, Hideo,Toyooka, Naoki,Matsuya, Yuji
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p. 3510 - 3513
(2012/07/31)
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- New access to a tricyclo[3.2.1.02,7]oct-3-ene structure
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A thermally induced reaction cascade including an electrocyclic rearrangement, two Diels-Alder reactions and a 1,4-elimination from a simple cyclobutene carbonate can explain the synthesis of a complex tricyclo[3.2.1.02,7]oct-3-ene core structu
- Dubarle-Offner, Julien,Marrot, Jér?me,Rager, Marie-No?lle,Le Bideau, Franck,Jaouen, Gérard
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p. 800 - 802
(2007/12/25)
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- The intermediacy of oxycyclobutenes in the synthesis and reactions of cyclobutenones and cyclobutenols
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Vinylcyclobutenol 7, generated via the singlet oxygenation of alkylidenecyclobutene 5, rearranges at room temperature to a solvent dependent mixture of isomeric dienones 10 and 11. Alkylidenecyclobutene 5 was prepared in turn via an inverse Wittig additio
- Frimer, Aryeh A.,Pizem, Hillel
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p. 12175 - 12186
(2007/10/03)
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- Preparation and Photosensitized Oxidation of Isopropylidenecyclobutanes and -cyclobutenes
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Isopropylidenecyclobutanes 2-5 underwent facile ene reaction with singlet dioxygen, yielding (upon Ph3P reduction) the corresponding pairs of epimeric allylic alcohols 9 and 10, 11 and 12, 13 and 14, and 15 and 16, respectively.A combination of spectral evidence and molecular modeling studies were utilized in the structural assignment of the epimers.The data clearly indicate that steric considerations play an important role in determining the face of the ring which 1O2 approaches.Isopropylidenecyclobutenes 6 and 7 reacted with singlet oxygen more slowly than their monoolefinic analogs, yielding upon reduction allylic alcohols 21b and 22, respectively.Benzo analog 7 also generated a small and solvent-dependent amount of isomeric aldehydes 23 and 24, presumably via a free-radical mechanism. n-Butyl diene 8 underwent rapid photosensitized oxygenation producing allylic alcohol 35 (as the 1O2 ene product) and dione 37 (the Hock-cleavage product of allylic hydroperoxide 39, formed in turn via a free-radical route) in a 1:9 ratio.Ab initio (STO-3G) calculations confirm that, in their lowest energy conformations, compounds 2-8 are planar with the methylene ring hydrogens displaced ca. 36 deg from the perpendicular.As a result, only exocyclic ene product is formed, since 1O2 strongly prefers axial or pseudoaxial allylic hydrogens.These calculations combined with the relative rate data suggest that the initial interaction between the electrophilic 1O2 and alkylidenecyclobutenes involves both ends of the singlet dioxygen molecule, in which the "front" end attacks the reactive exocyclic double bond while the "back" end obtains stabilization by interacting with the more electron rich but unreactive endocyclic olefin linkage.Because of this added, and presumably substantial, stabilization, the relative rates within this system are determined in part by the orbital coefficients at the latter olefinic center.
- Frimer, Aryeh A.,Weiss, Joseph,Gottlieb, Hugo E.,Wolk, Joel L.
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p. 780 - 792
(2007/10/02)
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- A GENERAL METHOD FOR THE REDUCTIVE DECHLORINATION OF 4,4-DICHLOROCYCLOBUTENONES
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Exposure of 4,4-dichlorocyclobutenones to the action of zinc dust in ethanol containing 5 equiv each of AcOH and TMEDA results in smooth reductive dechlorination producing simple cyclobutenones.
- Danheiser, Rick L.,Savariar, Selvaraj
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p. 3299 - 3302
(2007/10/02)
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- Synthesis, Regiochemistry, and Reactions of Dichlorocyclobutenones
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Dichlorocyclobutenones previously obtained only with difficulty were prepared by the cycloaddition of dichloroketene with alkynes in the presence of phosphorus oxychloride in fair to good yields.The regiochemistry of addition can be rationalized on the ba
- Hassner, Alfred,Dillon, John L.
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p. 3382 - 3386
(2007/10/02)
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- THE SILA-PUMMERER REARRANGEMENT OF 1-ALKYL-3-PHENYLSULFINYL-3-TRIMETHYLSILYLCYCLOBUTANOLS. A NEW METHOD FOR THE PREPARATION OF 3-ALKYL-2-CYCLOBUTENONES
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3-Alkyl-2-cyclobutenones were produced by the sila-Pummerer rearrangement of 1-acetoxy-1-alkyl-3-phenylsulfinyl-3-trimethylsilylcyclobutanes followed by hydrolysis. β-Phenylthio-α,β- and β,γ-unsaturated ketones were major products when the corresponding cyclobutanols were employed.
- Takeda, Takeshi,Tsuchida, Toshio,Ando, Kazuo,Fujiwara, Tooru
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p. 549 - 552
(2007/10/02)
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