- 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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- Catalytic enantioselective conjugate reduction of lactones and lactams
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A dramatic acceleration of the enantioselective copper-catalyzed conjugate reduction of α,β-unsaturated lactones, lactams, and esters is reported upon addition of alcohol additives. Good to excellent yields and enantioselectivities were realized using a catalyst generated in situ from CuCl2·H2O, t-BuONa, p-tol-BINAP, and PMHS, and this methodology was applied to the synthesis of (-)-Paroxetine.
- Hughes, Gregory,Kimura, Masanari,Buchwald, Stephen L.
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p. 11253 - 11258
(2007/10/03)
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- Preparation and reactions of 3,4-bisstannyl-2(5H)furanones
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Bistributylstannyl-2(5H)-furanone 4a has been prepared from 3-(tetrahydropyran-2-yl)oxy but-2-ynoate and shown to exhibit good selectivity in its Stille reactions with a range of halogenated compounds, leading to 4-substituted-3-stannyl-2(5H)-furanones, in generally moderate yield. Under certain reaction conditions, doubly substituted products were also isolated from the reactions. The 3,4-bistrimethylstannyl furanone, 4b, corresponding to 4a was prepared, but decomposed during all attempts to execute Stille reactions upon it.
- Carter, Neil B,Mabon, Ross,Richec?ur, Alexandre M.E,Sweeney
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p. 9117 - 9129
(2007/10/03)
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- A short synthesis of biologically active lignan analogues
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β-Benzyl-γ-butyrolactones were synthesized in four transition metal catalysed reactions from butynediol, and alkylated to afford new, biologically active lignan analogues.
- Kamlage,Sefkow,Pool-Zobel,Peter
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p. 331 - 332
(2007/10/03)
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- 3-Phenylselanylfuran-2(5H)-one: A versatile building block in the synthesis of lignans. A new approach towards 3,4-dibenzyl γ-butyrolactones
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Ready available 3-phenylselanylfuran-2(5H)-one undergoes tandem conjugate addition-alkylation by organocopper reagents to afford, with good yields and diastereoselectivities, 3,4-disubstituted-3-phenylselanyl-γ- butyrolactones, which can be transformed into naturally occurring compounds, such as lignans.
- Bella, Marco,Piancatelli, Giovanni,Pigro, Maria Cristina
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p. 12387 - 12398
(2007/10/03)
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- Furan-2(3H)- and -2(5H)-ones. Part 6. Di-?-methane rearrangement of the α-substituted 4-benzylfuran-2(5H)-one system
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The effect of the 'central methane' substitution on the di-?-methane rearrangement in 4-benzyl-2,5-dihydrofuran-2-ones 8a-d was investigated.Significant enhancement of efficiency in the rearrangement leading in high combined yields to two isomeric products, endo-12 and exo-12, is discussed in terms of both the substituent effects at the benzylic carbon and the restrained features of the ring-enrolled ?-system.The origin of the difference in chemoselectivity compared with that of the 3-benzyl counterpart 5 where a photoarylated product 6 resulted upon photoirradiation was also investigated, and was rationalized by postulating a higher reactivity at the β-position of the enone system.
- Muraoka, Osamu,Tanabe, Genzoh,Higachiura, Mie,Minematsu, Toshie,Momose, Takefumi
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p. 1437 - 1444
(2007/10/02)
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- Synthesis of butenolides via palladium-promoted cyclization of acyclic allylic esters of chloromercurioacetic acid
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Acyclic allylic esters of chloromercurioacetic acid react with Li2PdCl4 to afford good yields of butenolides.
- Larock,Stinn,Kuo
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- Analogues of γ-hydroxybutyric acid. Synthesis and binding studies
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Substituted 4-hydroxybutyric (GHB) or trans-4-hydroxycrotonic acids (T-HCA) and structurally related compounds were synthesized and submitted to [3H]GHB binding. Structure-activity relationship studies highlighted for [3H]GHB binding (a) the necessity of a nonlactonic, relatively extended conformation of the γ-hydroxybutyric chain, (b) the existence of some bulk tolerance in the vicinity of the hydroxyl group, and (c) the high sensitivity toward isosteric replacement of the carboxyl or the hydroxyl groups. T-HCA has been recently identified as a naturally occurring substance in the central nervous system (CNS) and shows a better affinity than GHB. Our findings are in favor of the presence in the CNS of specific GHB binding sites, which are different from the GABA and the picrotoxin binding sites, and for which T-HCA may be an endogenous ligand.
- Bourguignon,Schoenfelder,Schmitt,Wermuth,Hechler,Charlier,Maitre
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p. 893 - 897
(2007/10/02)
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- Synthesis of 4-Alkyl-2(5H)-furanones
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An alternative method for the synthesis of 4-alkyl-2(5H)-furanones is described.Intramolecular carbene addition reaction of α-diazo compounds (4) in the presence of rhodium acetate or copper acetylacetonate furnished the bicyclic compounds (5), which were subjected to cyclopropane ring-opening reaction to give the 4-alkyl-4,5-dihydrofuran-2(3H)-ones (6) regioselectively.These compounds (6) were further converted into 4-alkyl-2(5H)-furanones (14) in several steps.Keywords - carbene; intramolecular addition; butenolide; cyclopropanation; ring-opening reaction
- Kametani, Tetsuji,Katoh, Tadashi,Tsubuki, Masayoshi,Honda, Toshio
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- A SIMPLE ROUTE TO Δ2-BUTENOLIDES FROM CONJUGATED ALDEHYDES
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A variety of Δ2-butenolides may be synthesized by oxidation of the O-trimethylsilylcyanohydrins of α,β-unsaturated aldehydes using pyridinium dichromate in dimethylformamide.
- Corey, E. J.,Schmidt, Greg
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p. 731 - 734
(2007/10/02)
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