- Oxidative Cyclization of β,γ-Unsaturated Carboxylic Acids Using Hypervalent Iodine Reagents: An Efficient Synthesis of 4-Substituted Furan-2-ones
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The oxidative cyclization of β-substituted β,γ-unsaturated carboxylic acids using a hypervalent iodine reagent to provide 4-substituted furan-2-one products, is reported. In this cyclization, the use of a highly electrophilic PhI(OTf) 2, which is in situ prepared from PhI(OAc) 2 and Me 3 SiOTf, is crucial. Depending on the substitution pattern at the α-position of the substrates, furan-2(5 H)-ones or furan-2(3 H)-ones are produced. Thus, the present method offers a useful tool for accessing various types of 4-substituted furan-2-ones that are important structural motifs in the field of organic chemistry and medicinal chemistry.
- Kiyokawa, Kensuke,Takemoto, Kenta,Yahata, Shunsuke,Kojima, Takumi,Minakata, Satoshi
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supporting information
p. 2907 - 2912
(2017/06/27)
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- Palladium-catalyzed hydrodehalogenation of butenolides: An efficient and sustainable access to β-arylbutenolides
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Several α-unsubstituted β-arylbutenolides have been prepared in 69–92% yield by reductive dehalogenation of α-halo-β-arylbutenolides. The latter were assembled in a single-step from α,β-dihalobutenolides, which are accessible on a large-scale from biomass-derived furfural. Our dehalogenation protocol is illustrated by a new synthesis of the marine antibiotics rubrolide E and F, and 3″-bromorubrolide F.
- Karak, Milandip,Barbosa, Luiz C.A.,Maltha, Celia R.A.,Silva, Thiago M.,Boukouvalas, John
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p. 2830 - 2834
(2017/06/27)
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- Hg/Pt-catalyzed conversion of bromo alkynamines/alkynols to saturated and unsaturated γ-butyrolactams/lactones via intramolecular electrophilic cyclization
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Convenient and general Hg(ii)/Pt(iv) catalyzed syntheses of γ-butyrolactams and α,β-unsaturated γ-butyrolactones/lactams are described via intramolecular electrophilic cyclizations of bromoalkynes with tosylamino and hydroxyl tethers. The reaction features the use of wet solvents, the exclusion of any base and additive, mild conditions and practical yields. We also synthesised few chiral lactams through this pathway. Additionally, it is shown that the NHTs group distanced further from the homopropargylic position assists regioselective bromoalkyne hydration to yield useful α-bromoketones. Furthermore, Boc protected bromo homo propargyl amines undergo 6-endo-dig cyclization through Boc oxygen to give bromomethylene substituted oxazinones.
- Kumar, Yalla Kiran,Kumar, Gadi Ranjith,Reddy, Maddi Sridhar
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p. 1252 - 1260
(2016/02/03)
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- Highly Regioselective Palladium-Catalyzed Carboxylation of Allylic Alcohols with CO2
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Various allylic alcohols were carboxylated in the presence of a catalytic amount of PdCl2 and PPh3 using ZnEt2 as a stoichiometric transmetalation agent under a CO2 atmosphere (1atm). This carboxylation proceeded in a highly regioselective manner to afford branched carboxylic acids predominantly. The β,γ-unsaturated carboxylic acid thus obtained was successfully converted into an optically active γ-butyrolactone, a known intermediate of (R)-baclofen.
- Mita, Tsuyoshi,Higuchi, Yuki,Sato, Yoshihiro
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supporting information
p. 16391 - 16394
(2015/11/09)
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- Palladium-catalyzed cross-coupling reactions of 4-tosyl-2(5H)-furanone with boronic acids: A facile and efficient route to generate 4-substituted 2(5H)-furanones
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An efficient and facile synthesis of 4-substituted 2(5H)-furanones using palladium catalyzed cross-coupling reactions between 4-tosyl-2(5H)-furanone and boronic acids is reported herein.
- Wu, Jie,Zhu, Qiang,Wang, Lisha,Fathi, Reza,Yang, Zhen
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p. 670 - 673
(2007/10/03)
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- An expeditious synthesis of 4-aryl-γ-butyrolactones, -furan-2(5H)-ones and -5-alkoxyfuran-2(5H)-ones via Heck-reaction of arenediazonium salts with 2,5-dihydrofuran
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An exceptionally simple and short synthetic sequence to 4-substituted furan-2(5H)-ones involving a Heck reaction on 2,5-dihydrofuran and subsequent iterative NBS oxidation is described.
- Mehta, Goverdhan,Sengupta, Saumitra
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p. 8625 - 8626
(2007/10/03)
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- Simple preparation of 4-aryl- and 4-alkyl-2(5H)-furanones from β-substituted crotonic esters
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Treatment of β-aryl- or β-alkylcrotonic esters with selenium dioxide in acetic acid in the presence of a catalytic amount of perchloric acid gave 4-substituted 2(5H)-furanones in moderate to good yields.
- Kagabu,Shimizu,Ito,Moriya
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p. 830 - 832
(2007/10/02)
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- Reductive Carbonylation of Acetylenes under Water-Gas Shift Reaction Conditions. Synthesis of Furan-2(5H)-ones from Terminal and Non-substituted Acetylenes
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Under water-gas reaction conditions terminal and non-substituted acetylenes are selectively converted into furan-2(5H)-ones by catalysis with a rhodium carbonyl cluster.
- Joh, Takashi,Nagata, Hiroyuki,Takahashi, Shigetoshi
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p. 1305 - 1308
(2007/10/02)
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- INVESTIGATIONS IN THE SERIES OF SUBSTITUTED BUTAN- AND BUTENOLIDES. III. SYNTHESIS OF ARYLBUTAN- AND ARYLBUTENOLIDES AND THEIR PROPERTIES
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A new method was developed for the synthesis of 2-aryl- and 3-aryl-2-buten-4-olides by the arylation of 2-buten-4-olide with diazonium halides in the presence of cupric chloride as catalyst.The intermediate products of the reaction are the corresponding arylchlorobutanolides. 4-R-Methylene-3-aryl-2-buten-4-olides and 4-hydroxy-3-aryl-2-butenamides were obtained in the reaction of 3-aryl-2-buten-4-olides with aldehydes and primary aliphatic amines respectively.Some of the synthesized compounds have antimicrobial and growth-stimulant activity.
- Chellar, N. S.,Badovskaya, L. A.,Ignatenko, A. V.
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p. 1775 - 1779
(2007/10/02)
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