1575-48-0Relevant academic research and scientific papers
Gold-catalyzed cascade oxidative cyclization and arylation of allenoates
Zhang, Rui,Xu, Qin,Chen, Kai,Gu, Peng,Shi, Min
supporting information, p. 7366 - 7371 (2013/11/19)
An AuI/AuIII catalytic system was found to be effective for the cascade oxidative arylation and cyclization of allenoates with arylboronic acids to give the corresponding cyclic adducts in moderate yields. This reaction system constitutes a new method for the synthesis of β-aryl-γ-butenolides under mild conditions. Based on the previous mechanistic studies, a proposed AuI/AuIII redox catalytic cycle has been outlined. An AuI/AuIII catalytic system was found to be effective for the cascade oxidative arylation and cyclization of allenoates with various arylboronic acids to give the corresponding cyclic adducts in moderate yields. This reaction system enabled the synthesis β-aryl-γ-butenolides under mild conditions. Based on previous mechanistic studies, an AuI/AuIII redox catalytic cycle has been outlined. Copyright
Cu(II)-catalyzed acylation by thiol esters under neutral conditions: Tandem acylation-wittig reaction leading to a one-pot synthesis of butenolides
Matsuo, Kazumasa,Shindo, Mitsuru
supporting information; experimental part, p. 5346 - 5349 (2011/01/05)
The first catalytic acylation of alcohols with a thiol ester present in Wittig reagents under neutral conditions catalyzed by the Cu(II) salt through a push-pull mechanism is reported. Furthermore, a new methodology for the one-pot lactonization of acyloins by a copper catalyst is developed. The synthetic utility of this method for the synthesis of natural products is shown.
Selective synthesis of unsymmetrical 3,4-disubstituted and 4-substituted 2(5H)-furanones
Rossi,Bellina,Raugei
, p. 1749 - 1752 (2007/10/03)
Easily available 3,4-dibromo-2(5H)-furanone undergoes regioselective palladium-catalyzed reaction with aryl(trialkyl)stannanes to give the corresponding 4-aryl-3-bromo-2(5H)-furanones in satisfactory yields. These monobromo derivatives have proven to be useful precursors to unsymmetrical 3,4-diaryl-2(5H)-furanones, 4-aryl-3-methyl-2(5H)-furanones and 4-aryl-2(5H)-furanones.
Facile access to 4-aryl-2(5H)-furanones by suzuki cross coupling: Efficient synthesis of rubrolides C and E
Boukouvalas, John,Lachance, Nicolas,Ouellet, Michel,Trudeau, Martin
, p. 7665 - 7668 (2007/10/03)
The Pd(0)-catalyzed cross coupling between 4-bromo-2(5H)-furanones and arylboronic acids provides the corresponding 4-aryl-2(5H)-furanones in yields of 61-85%. By using this method in conjunction with furanolate chemistry, the marine antibiotics rubrolide C and E have been synthesized in highly efficient fashion (4 steps, overall yield = 61 and 56% respectively) from β- tetronic acid.
The reaction of α-diazo-β-hydroxy esters with boron trifluoride etherate: Generation and rearrangement of destabilized vinyl cations. A detailed experimental and theoretical study
Pellicciari, Roberto,Natalini, Benedetto,Sadeghpour, Bahman M.,Marinozzi, Maura,Snyder, James P.,Williamson, Bobby L.,Kuethe, Jeffrey T.,Padwa, Albert
, p. 1 - 12 (2007/10/03)
Cyclic ethyl 2-diazo-3-hydroxy carboxylates were prepared by treating ethyl diazoacetate with LDA followed by reaction with a series of cyclic ketones. Further treatment of these α-diazo-β-hydroxy esters with boron trifluoride etherate in various solvents affords an unusual array of products. Product types and ratios were found to be strongly dependent on ring size and the solvent used. The reaction proceeds by Lewis acid complexation of the alcohol functionality of the diazo hydroxy ester with BF3 etherate followed by neighboring-group participation of the diazo moiety to generate a cycloalkylidene diazonium salt. Loss of nitrogen produces a highly reactive, destabilized, linear vinyl cation. Ring expansion via a 1,2-methylene shift leads to the formation of a more stable, bent cycloalkenyl vinyl cation. A subsequent 1,2-methylene shift results in ring contraction ultimately leading to a stable allylic cation. This cation is either trapped by the solvent or else undergoes cyclization with the adjacent ester group to give a lactone. Computational studies at the 6-31G* level were performed to determine the geometry of the optimized vinyl cations. Relative energies suggest a moderate energy gain for isomerization of the initial vinyl cation V1 to the rearranged vinyl cation V2 followed by a large stabilization in energy for subsequent conversion to the allyl cation A1. Compared with isolated product distributions, the energy profiles suggest kinetically-controlled V1 → V2 → A1 migrations. Finally, the calculations suggest that in diethyl ether the carbocations may be coordinated to a molecule of solvent resulting in "protected" cationic intermediates with nonlinear geometries.
Furan-2(3H)- and -2(5H)-ones. Part 6. Di-?-methane rearrangement of the α-substituted 4-benzylfuran-2(5H)-one system
Muraoka, Osamu,Tanabe, Genzoh,Higachiura, Mie,Minematsu, Toshie,Momose, Takefumi
, p. 1437 - 1444 (2007/10/02)
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.
Rhodium Complex-Catalyzed Desilylative Cyclocarbonylation of 1-Aryl-2-(trimethylsilyl)acetylenes: A New Route to 2,3-Dihydro-1H-inden-1-ones
Takeuchi, Ryo,Yasue, Hiroyuki
, p. 5386 - 5392 (2007/10/02)
Under water gas shift reaction conditions, 1-aryl-2-(trimethylsilyl)acetylenes undergo Rh-catalyzed desilylative cyclocarbonylation to give 2,3-dihydro-1H-inden-1-ones and trimethylsilanol.A wide variety of functional groups, such as methoxy, chloro, acetyl, ethoxycarbonyl, cyano, and trifluoromethyl, are tolerated on the aromatic ring under the reaction conditions.The products were obtained in good to excellent yield whether the substituent on the aromatic ring was electron-donating or electron-withdrawing.The cyclizations of substrates bearing a meta substituent onthe aromatic ring regiospecifically gave 5-substituted-2,3-dihydro-1H-inden-1-ones except when the meta substituent was a methoxy group.The desilylative cyclocarbonylation is an alternative to the conventional preparation of 2,3-dihydro-1H-inden-1-ones, an intramolecular Friedel-Crafts acylation.A possible mechanism for the process is described.
Preparation of α-Hydroxy-γ-lactones and their Application in the Synthesis of α,β-Butenolides, α-Alkylidene-γ-lactones and Furans
Munoz, A. Heber,Tamariz, Joaquin,Jimenez, Rogelio,Mora, Gustavo Garcia de la
, p. 501 - 522 (2007/10/02)
A straightforward synthesis of α-hydroxy-γ-butyrolactones was carried out by condensation reaction of the lithium anion of ethoxyethyl-protected cyanohydrins with epoxides, followed by acidic treatment.Synthetic applications of these synthons in the preparation of interesting α,β-butenolides, α-alkylidene-γ-lactones and furans are described.
Rhodium-Catalysed Reactions of Propargylamines with CO/H2. Formation of Pyrroles and Butenolides
Campi, Eva M.,Fallon, Gary D.,Jackson, W. Roy,Nilsson, Ylva
, p. 1167 - 1178 (2007/10/02)
Rhodium-catalysed reactions of (arylpropargyl)amines with CO/H2 give β-arylpyrroles in good yields.Reactions of (alkylpropargyl)amines gave alkylpyrroles together with butenolides which are formed in an unusual reaction that probably involves double carbonylation, reduction of one carbonyl function and removal of the amine function by hydrogenolysis.The single-crystal X-ray structure of 5-methyl-N,3-diphenylpyrrole-2-carboxamide is recorded.
ANODIC SYNTHESIS OF BUTENOLIDES FROM β-ETHYLENIC ESTERS DOUBLE CYCLIZATION IN THE PRESENCE OF OLEFINS
Delaunay, J.,Orliac-Le Moing, A.,Simonet, J.
, p. 7089 - 7094 (2007/10/02)
Anodic oxidation of β-ethylenic esters yields butenolides 2.In the presence of 1-phenyl-1-propene or α,β-disubstituted indenones a double cyclization takes place to yield more complex butenolides
