- A Copper(I)-Catalyzed Addition/Annulation Sequence for the Two-Component Synthesis of γ-Ylidenebutenolides
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A highly efficient Cu(I)-catalyzed addition/annulation sequence has been developed for the synthesis of (Z)-ylidenebutenolides employing readily available α-ketoacids and alkynes as substrates. The reactions employ a simple commercially available Cu(I)-catalyst, display good substrate scope, and deliver products with high stereoselectivity. The synthetic utility of the method is demonstrated by the straightforward derivatization of the ylidenebutenolides into a diverse range of heterocycles, and also by the preparation of the natural product bovolide, and analogs thereof.
- Seo, Sangwon,Willis, Michael C.
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p. 4556 - 4559
(2017/09/11)
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- Facile synthesis of γ-alkylidenebutenolides from Morita-Baylis- Hillman adducts
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An expedient synthetic procedure of γ-alkylidenebutenolides was developed via a sequential indium-mediated Barbier-type reaction of Morita-Baylis-Hillman bromide with aldehyde, lactonization, and double-bond isomerization. Various γ-alkylidenebutenolides
- Park, Bo Ram,Kim, Ko Hoon,Lim, Jin Woo,Kim, Jae Nyoung
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- Carboxylate-directed tandem functionalisations of α,β- dihaloalkenoic acids with 1-alkynes: A straightforward access to (Z)-configured, α,β-substituted γ-alkylidenebutenolides
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An easy and mild copper(I)-catalysed lactonisation of readily available (E)-2,3-dihalopropenoic acid derivatives regio- and stereoselectively leads to rarely described (Z)-3-halo-5-ylidene-5H-furan-2-ones. These compounds are subsequently able to undergo classical Pd-catalysed cross-coupling reactions, providing 3-substituted and 3,4-disubstituted 5-ylidene-5H-furan-2-ones (see scheme).
- Inack Ngi, Samuel,Cherry, Khalil,Héran, Virginie,Commeiras, Laurent,Parrain, Jean-Luc,Duchêne, Alain,Abarbri, Mohamed,Thibonnet, Jér?me
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supporting information; experimental part
p. 13692 - 13696
(2012/01/06)
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- Synthesis of 5-(bromomethylene)furan-2(5H)-ones and 3-(bromomethylene) isobenzofuran-1(3H)-ones as inhibitors of microbial quorum sensing
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(E)- and (Z)-5-(Bromomethylene)furan-2(5H)-ones and (E)- and (Z)-3-(bromomethylene)isobenzofuran-1(3H)-ones have been prepared starting from commercially available maleic anhydrides and phthalic anhydrides, respectively. A debrominative decarboxylation or a bromodecarboxylation reaction is a key step in the synthesis. The furanones were investigated for their ability to interfere with microbial communication and biofilm formation by Staphylococcus epidermidis. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
- Benneche, Tore,Hussain, Zainab,Aamdal Scheie, Anne,Loenn-Stensrud, Jessica
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experimental part
p. 1567 - 1572
(2009/04/10)
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- A novel protocol for the stereoselective synthesis of variously substituted (Z)-5-ylidene-5H-furan-2-ones
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The Pd(II)- or Ag(I)-catalyzed lactonization of easily available (E)-4- (1-alkynyl)-2-bromopropenoic acids provides (Z)-3-bromo-5-ylidene-5H-furan- 2-ones, 5. These compounds, which represent an unpreviously reported class of (Z)-alkylidenebutenolides, are able to undergo Pd-catalyzed cross-coupling reactions with arylzinc halides, tetraalkylstannanes or alkenylstannanes to provide the corresponding 3-substituted (Z)-5-ylidene-5H-furan-2-ones, 1. The new procedure for the preparation of compounds 1 has been employed in a new synthesis of the butter flavour component bovolide.
- Rossi, Renzo,Bellina, Fabio,Mannina, Luisa
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p. 3017 - 3020
(2007/10/03)
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- Acylpalladation of internal alkynes and palladium-catalyzed carbonylation of (Z)-β-iodoenones and related derivatives producing γ-lactones and γ-lactams
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The reaction of either an internal alkyne-organic halide mixture or (Z)-β-iodoenones with CO in the presence of a Pd-phosphine catalyst, e.g., Cl2Pd(PPh3)2, can give one of the three discrete types of compounds as the major products depending on the substrate structure and the reaction conditions. Those substrates which are convertible to (Z)-γ-oxo-α,β-unsaturated acylpalladium derivatives lacking δ-H atoms are converted to the corresponding 2-butenolides (13) in the presence of water, which serves as a H donor. Carbon monoxide most likely is the source of two electrons. Either in the absence of water (or any other suitable H source) or in the presence of some factors disfavoring the butenolide formation, the same reaction gives the corresponding dimeric product (16). Even in cases where there is an α-H atom in the α-substitutent, 1,4-elimination products (11), reported to be the major products in a related Pd-catalyzed reaction of terminal alkyne-aryl iodide mixtures with CO, were not detected. In sharp contrast, those substrates which can give rise to (Z)-γ-oxo-α,β-unsaturated acylpalladium derivatives containing δ-H atoms give, under comparable reaction conditions, enol lactones (12), i.e., (Z)-3-alkylidene-2-butenolides, contaminated with only very minor amounts of 22 even in cases where an excess (4 equiv) of water was present. The required (Z)-β-iodoenones can be readily prepared in one pot via ZrCp2-promoted cyclization of alkynes with nitriles. The ready availability of the starting compounds and the high Z stereoselectivity make the overall sequence an attractive synthetic route to 12. The courses of the Pd-catalyzed carbonylation reactions of (Z)-β-iodo-α,β-unsaturated imines 23 closely parallel the reactions of enones and produce the corresponding lactams, i.e., 24 and 25.
- Copéret, Christophe,Sugihara, Takumichi,Wu, Guangzhong,Shimoyama, Izumi,Negishi, Ei-Ichi
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p. 3422 - 3431
(2007/10/02)
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