Carbon dioxide triggered and copper-catalyzed domino reaction: efficient construction of highly substituted 3(2H)-furanones from nitriles and propargylic alcohols

A novel carbon dioxide triggered and copper-catalyzed domino reaction for the efficient synthesis of highly substituted 3(2H)-furanones from readily available nitriles and propargylic alcohols has been developed. Carbon dioxide is a prerequisite for achieving the present catalytic transformation, and one of the oxygen atoms of carbon dioxide is incorporated into the 3(2H)-furanones. Nitriles not only act as the reaction solvent but also as the reactant; copper salts play dual roles of activating both the propargylic alcohols and nitriles.     

Gold-catalyzed highly efficient access to 3(2H)-furanones from 2-oxo-3-butynoates and related compounds

[reaction: see text] The gold-catalyzed cyclization reactions of 2-oxo-3-butynoic esters or disubstituted-1,2-diones with a variety of nucleophiles are described, which offer an efficient and straightforward route to substituted 3(2H)-furanones under mild reaction conditions. The Au(III) catalysts are also highly effective in the hydration of these activated alkynes.     

Cyclohydrocarbonylation of substituted alkynes and tandem cyclohydrocarbonylation-CO insertion of alpha-keto alkynes catalyzed by immobilized Co-Rh heterobimetallic nanoparticles

The use of cobalt-rhodium (Co(2)Rh(2)) heterobimetallic nanoparticles in the cyclohydrocarbonylation of substituted alkynes and tandem cyclohydrocarbonylation-CO insertion of alpha-keto alkynes to give 2(3H)- or 2(5H)-furanones is described.     

A general method for alkylating 2(5H)-furanones; reduction of products to 3-, 2,3-, and 3,4-substituted furans

The cycloaddition of diazoalkanes, diazoesters and diazoketones to 2(5H)-furanones followed by thermal decomposition of the respective adducts is shown to provide a general method for the preparation of a variety of alkylated 2(5H)-furanones. Reduction of the latter compounds with diisobutylaluminum hydride affords the corresponding substituted furans in good yield.     

Intramolecular cycloadditions of alpha-allyloxycarbonylnitrones: stereoselective synthesis of 3-amino-2(5H)furanones

Treatment of furoisoxazolidines with NaH leads to functionalized 3-amino-2(5H)-furanones through a new rearrangement pattern of the isoxazolidine nucleus. This process has been usefully exploited for the synthesis of enantiomerically pure (5R)-3-alkylamino-5-methyl-2(5H)-furanones.     

Chemistry of polyenic and polyacetylenic compounds Communication 12. Hydration of tertiary diacetylenic alcohols and glycols

Summary A study was made of the hydration of tertiary diacetylenic glycols under the action of aqueous dimethylamine solution, which leads to substituted 3(2H)-furanones. Under the conditions of acid hydration, 2-methyl-3,5-hexadiyn2-ol also gives the corresponding furanone.     

Pd(OAc)2-catalyzed cyclization of 2,3-allenoic acids in the presence of terminal alpha,beta-unsaturated alkynones: a one-pot highly stereoselective synthesis of 4-(3'-oxo-1'(E)-alkenyl)-2(5H)-furanones

The Pd(OAc) 2-catalyzed cyclization reaction of 2,3-allenoic acids in the presence of terminal alpha,beta-unsaturated alkynones afforded an E/ Z mixture of 4-(3'-oxo-1'-alkenyl)-2(5 H)-furanones. A subsequent complete isomerization of the Z-isomer to E-isomer was observed in DMSO at 90 degrees C, which led to a highly stereoselective synthesis of 4-(3'-oxo-1'( E)-alkenyl)-2(5 H)-furanones. A possible mechanism is proposed.     

Efficient synthesis of 3-chloromethyl-2(5H)-furanones and 3-chloromethyl-5,6-dihydropyran-2-ones via the PdCl2-catalyzed chlorocyclocarbonylation of 2,3- or 3,4-allenols

A mild and efficient methodology involving PdCl2-catalyzed chlorocyclocarbonylation of 2,3- or 3,4-allenols with CuCl2 for the synthesis of 3-chloromethyl-2(5H)-furanones and 3-chloromethyl-5,6-dihydropyran-2-ones was developed. This reaction proceeded in a highly regioselective manner, i.e., the chlorine atom was introduced to the terminal position of the allene moiety while the lactone linkage was formed between the center carbon atom of the allene moiety and the hydroxyl oxygen, which was established by the X-ray single crystal diffraction study of gamma-lactone 3p. The highly optically active 3-chloromethyl-2(5H)-furanones could be easily prepared from the readily available optically active 2,3-allenols. A mechanism for this reaction was proposed.     

Synthesis of 4-iodo-3-furanones utilizing electrophile-induced tandem cyclization/1,2-migration reactions

Two protocols for the construction of 4-iodo-3-furanones through a sequence consisting of cyclization and 1,2-migration of 2-alkynyl-2-silyloxy carbonyl compounds were developed. In one, electrophilic cyclization is directly induced by N-iodosuccinimide (NIS). In the second less limited variant, AuCl3 catalyzes the tandem reaction in the presence of NIS to provide highly substituted heterocycles in moderate to excellent yields.     

Regiospecific Displacement of the C-B Bond of Tris[4-(substituted)furan-3-yl]boroxines with C-Sn Bond and C-O Bond: Syntheses of 3,4-Disubstituted Furans and 4-Substituted-3(2H)-furanones,

Tris[4-(substituted)furan-3-yl]boroxines 2 , prepared from the corresponding 4-(substituted)-3-(trimethylsilyl) furan 1, were converted successfully to 4-(substituted)-3-(tributylstannyl)furans 3 through palladium-catalyzed cross-coupling reactions with tributylstannyl chloride. Palladium-catalyzed cross-coupling reactions of 3 with organohalides afforded 3,4-disubstituted furans 4 . Regiospecific iodination of 4-(trimethylsilyl)-3-((tributylstannyl) furan ( 3a ) gave 4-iodo-3-(trimethylsilyl)furan ( 5 ), which reacted with excess ethyl acrylate under a common Heck-condition to produce 2,3-bis(trans-ethoxycarbonylvinyl)-4-(trimethylsilyl)furan ( 6 ). A thermal 6-electrocyclic reaction followed by dehydration converted 6 into benzo[2,3-6]furan 8 . Oxidation of 2 generated the corresponding 4-substituted-3(2H)-furanones 9 .     

PdCl2-catalyzed oxidative cycloisomerization of 3-cyclopropylideneprop-2-en-1-ones

A novel PdCl(2)-catalyzed oxidative cycloisomerization of 3-cyclopropylideneprop-2-en-1-ones, providing a facile synthesis of highly strained functionalized 2-alkylidenecyclobutanones via furan-fused cyclobutene intermediates, is reported. An interesting route to 2(3H)-furanones with a spiro-cyclopropane unit from the obtained 2-alkylidenecyclobutanones via a ring-contraction rearrangement reaction is also realized.     

Preparation et reactions de Diels et Alder des alcenyl-5(3H)-furannones-2

Isomerization of readily available 5-alkenyl 2-(5$\text{H}$)-furanones 1 generated from aldehydes and propiolate anion to 5-alkenyl 2-(3$\text{H}$)-furanones 2 by base treatment provides a new and convenient access by mild Diels-Alder reaction in water to substituted cyclohexanofuranones.     

Transformation of alkyl esters of 4-oxo-3-phenylthioalkanoic acids into substituted 4-phenylthio-2(5H)-furanones and 3-phenylthiofurans

When the solutions of methyl and ethyl esters of 4-oxo-3-phenylthioalkanoic acids are boiled in toluene in the presence of p-toluene sulfonic acid, substituted 4-phenylthio-2(5H)-furanones are formed in good yields. In the reaction with diisobutylaluminum hydride or organomagnesium compounds, the latter convert into the corresponding 3-phenylthiofurans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 313–316, March, 1988.     

Hexafluoroacetone as protecting and activating reagent: reactions of hexafluoroacetone with α-keto acids

Hexafluoroacetone and α-keto acids react to give 5,5-bis(trifluoromethyl) substituted 2(5H)-furanones and/or 2,2-bis(trifluoromethyl)-1,3-dioxolan-4-ones depending upon the substituent pattern of the side chain of the acid. A fluoroanalogue of the natural product zymonic acid was obtained from ethyl 3,3,3-trifluoropyruvate and 2-oxosuccinic acid in one step.     

金属催化的2(5H)-呋喃酮反应研究进展

2(5H)-呋喃酮结构单元广泛存在于天然产物中,同时许多2(5H)-呋喃酮类化合物也是重要的有机合成中间体.因此,基于常见2(5H)-呋喃酮的有机合成研究近年来引起了人们的关注,尤其是金属催化的2(5H)-呋喃酮反应的地位日趋彰显重要,从而成为众多化学工作者的研究热点.按照反应类型的不同,对近年来金属催化的2(5H)-呋喃酮反应的研究进展进行了综述,主要包括Sonogashira,Suzuki,Stille等偶联反应,以及Michael加成反应、Friedel-Crafts烷基化反应、Baylis-Hillman反应、亲核取代反应、还原反应等.     

A facile solid-phase synthesis of substituted 2(5H)-furanones from polymer-supported alpha-selenocarboxylic acids

The synthesis of polystyrene-supported alpha-selenoacetic acid, alpha-selenopropionic acid, and alpha-selenophenylacetic acid is described. The reaction of the dilithio derivatives of polymer-supported alpha-selenocarboxylic acids with racemic epoxides or optically active styrene oxide afforded polystyrene-supported gamma-substituted alpha-selenobutyrolactones. The alpha-alkylation reaction of gamma-substituted polystyrene-supported alpha-selenobutyrolactones provided another route for the synthesis of polystyrene-supported alpha,gamma-disubstituted alpha-selenobutyrolactones. Subsequent oxidation-elimination with an excess of 30% hydrogen peroxide at room temperature afforded substituted (3- and 5-mono-; 3,4- and 3,5-di) 2(5H)-furanones in high yields and good purities.     

Transformation of fused bicyclic and tricyclic beta-lactones to fused gamma-lactones and 3(2H)-furanones via ring expansions and O-H insertions

A two-step strategy for conversion of beta-lactones to gamma-lactones and 3(2H)-furanones was developed involving initial acyl C-O cleavage leading to delta-hydroxy-alpha-diazo-beta-ketoesters and beta-ketophosphonates. Subsequent tandem Wolff rearrangement/lactonization of these alpha-diazo intermediates provided cis-fused gamma-lactones efficiently under photolytic or thermolytic conditions. In addition, cis-fused 3(2H)-furanones were obtained by rhodium(II)-catalyzed O-H insertion reactions of the delta-hydroxy-alpha-diazo intermediates.     

基于稳定的膦叶立德合成2(5H)-呋喃酮和2(5H)-吡咯酮作为细菌群体感应抑制剂的研究

利用稳定的乙酸乙酯基膦叶立德与含羰基化合物反应,合成了不同的2(5H)-呋喃酮,然后将获得的部分2(5H)-呋喃酮与醋酸铵反应转化为2(5H)-吡咯酮类化合物.所合成化合物均经1H NMR、13C NMR和MS等确认.通过测定所得到的化合物对于绿脓杆菌的最低抑菌浓度(MIC)来检验其抑菌活性;利用细莆生物膜染色实验来检测所得到的化合物对细菌群体感应系统和细菌生物膜的影响.活性实验结果表明,所得到的2(5H)-呋喃酮类化合物和2(5H)-吡咯酮类化合物均具有一定的抑制细菌群体感应的能力.     

5-(S)-孟氧基-3,4-二卤-2(5H)-呋喃酮与4-硝基邻苯二胺的Michael加成―消除反应

在Et3N作为碱的温和条件下,5-(S)-孟氧基-3,4-二卤-2(5H)-呋喃酮与芳香胺4-硝基邻苯二胺发生串联的Michael加成―消除反应,生成了新的含有苯环结构的5-孟氧基-4-氨基-3-卤-2(5H)-呋喃酮类化合物。新化合物的结构通过紫外―可见光谱(UV-Vis)、红外光谱(IR)、质谱(MS)、核磁共振氢谱(1H NMR)、核磁共振碳谱(13C NMR)和元素分析等表征证实。该多环结构卤代2(5H)-呋喃酮化合物的合成,能为某些多官能团的结构复杂的2(5H)-呋喃酮化合物的合成提供新途径。     

A New Synthesis of 3-Aryl-5-Arylmethylene-2(5H)-Furanones

A recent report about the synthesis of di and tri-substituted 2 (5H)-furanones starting from bromoaldehydes and potassium phenyl-acetate¹ prompts us to report our own studies on the preparation of 3-aryl-5-arylmethylene-2 (5H)-furanones (or butenolides) 1. We have earlier reported² a general method for the synthesis of 1 from phenylpropargyl aldehyde, 2 and arylacetic acids. Although several methods have been reported for the synthesis of the parent compound 1 (R = R₁ = Ph)^3–6, these methods have not been extended to other substituted furanones. Saikachi and Taniguchi⁷ prepared 1 (R = 5-nitro-2-thenyl, R₁ = 2-thenyl and 2-furyl) in 16–17% yields.