- Stereoselective Synthesis of cis-2-Ene-1,4-diones via Aerobic Oxidation of Substituted Furans Catalyzed by ABNO/HNO3
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We report a highly efficient and selective catalytic system, ABNO (9-azabicyclo-[3.3.1]nonane N-oxyl)/HNO3, for the aerobic oxidation of substituted furans to cis-2-ene-1,4-diones under mild reaction conditions using oxygen as the oxidant. The catalyst system is amenable to various substituted (mon-, di-, and tri-) furans and tolerates diverse functional groups, including cyano, nitro, naphthyl, ketone, ester, heterocycle, and even formyl groups. Based on the control and 18O-labeling experiments, the possible mechanism of the oxidation is proposed.
- Yang, Liqun,Wang, Jingyang,Wang, Yue,Li, Xiaotong,Liu, Wei,Zhang, Zhaoguo,Xie, Xiaomin
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p. 14311 - 14320
(2021/10/25)
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- One-pot transformation of simple furans into 4-Hydroxy-2-cyclopentenones in water
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A highly efficient one-pot transformation of readily accessible furans into 4-hydroxy-2-cyclopentenones in H2O, using singlet oxygen as oxidant, has been developed.
- Kalaitzakis, Dimitris,Triantafyllakis, Myron,Alexopoulou, Ioanna,Sofiadis, Manolis,Vassilikogiannakis, Georgios
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supporting information
p. 13201 - 13205
(2015/02/19)
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- Laccase-catalyzed stereoselective oxidative ring opening of 2,5-dialkylfurans into 2-ene-1,4-diones using air as an oxidant
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The laccase-catalyzed ring opening of 2,5-dimethylfuran using air as an oxidant stereoselectively yields (Z)- or (E)-3-hexene-2,5-dione depending on the mediator employed: with TEMPO the (Z)-3-hexene-2,5-dione is formed, while a combination of TEMPO and violuric acid gives (E)-3-hexene-2,5-dione. The (Z)-selective ring cleavage was extended to a variety of symmetrical and unsymmetrical 2,5-dialkylfurans. The Royal Society of Chemistry.
- Asta, Chimene,Conrad, Juergen,Mika, Sabine,Beifuss, Uwe
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supporting information; experimental part
p. 3066 - 3069
(2011/12/21)
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- An efficient furan synthesis using heterogeneous catalysis
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A wide variety of 3-alkyne-1,2-diols have been found to undergo exceptionally clean 5-endo-dig cyclisations followed by dehydration at ambient temperature to give the corresponding furans in essentially quantitative yields when exposed to 10 mol % of 10%
- Hayes, Simon J.,Knight, David W.,Menzies, Melanie D.,O'Halloran, Mark,Tan, Wen-Fei
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p. 7709 - 7712
(2008/03/30)
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- Novel Oxa-Cage Compounds: Synthesis, Structures, and the Formation Mechanism of Tetraacetal Oxa-Cages and Convex Tetraquinane Oxa-Cages
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Several novel tetraacetal oxa-cage compoundsa 5a-d and convex tetraquinane oxa-cage compounds 16a-d and 17b-d are synthesized from alkylfuranes in three steps.Ozonolysis of the cis-endo-1,4-diones 3a-d in dichloromethane at -78 deg C followed by reduction with dimethyl sulfide gives the oxa-cage 5a-d in high yields, respectively.The structures of these new tetraacetal oxa-cages are deduced from their spectral data and proven for the first time by X-ray analysis of the crystalline compound 5a.Ozonolysis of 3a-d in dichloromethane at -78 deg C followed by treatment with triethylamine gives the convex tetraquinane oxa-cages 16a-d and 17b-d in 85-90percent yields, respectively.The structures of these novel convex tetraquinane oxa-cages are finally proven by X-ray analysis of the crystalline compound 16a.Two reaction mechanisms via the common final ozonides are proposed for the formation of these two different types of oxa-cage compounds.The structures of the final ozonides formed by ozonolysis of the norbornene derivatives 3 are deduced to be 9 with endo stereochemistry on the basis of their spectral data and the formation of these two types of oxa-cages from the final ozonides.In reaction with the final ozonides, triethylamine is found to act as a base instead of a reducing agent, a different function from that of dimethyl sulfide.The synthesis of oxa-cages 24 and 25, which possess aromatic substituents dirctly on the skeleton, has also been accomplished.
- Wu, Hsien-Jen,Lin, Chu-Chung
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p. 7558 - 7566
(2007/10/03)
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