55004-95-0Relevant articles and documents
Manganese-catalyzed dehydrogenative Csp3-Csp2coupling of imidazo[1,2-a]pyridines with methyl ketones
Yao, Hua,Zhong, Xiaoyang,Wang, Bingqing,Lin, Sen,Liu, Lichi,Yan, Zhaohua
, p. 3479 - 3483 (2021/05/03)
A Mn(ii)-catalyzed efficient C-H alkylation of imidazoheterocycles with methyl ketones has been developedviadehydrogenative C(sp3)-C(sp2) coupling which can serve as a novel approach toward hydrocarboxylated imidazolopyridines. The merit of this strategy is illustrated by excellent functional group tolerance and the use of cheap and readily available starting materials.
Copper-catalyzed electrosynthesis of 1-acyl-2,2-diphenylcyclopropanes and their behaviour in acidic medium
Oudeyer, Sylvain,Léonel, Eric,Paugam, Jean Paul,Nédélec, Jean-Yves
, p. 1073 - 1081 (2007/10/03)
The formation of 1-acyl-2,2-diphenylcyclopropanes is performed under mild electrochemical conditions. These cyclopropane derivatives, through acid-catalyzed ring-opening, lead to γ,γ-diphenyl-β,γ-unsaturated carbonyl compounds which evolve into either substituted naphthalenes, or β-benzhydryl-α,β-cycloalkenones depending on the acyclic or cyclic nature of the intermediate allyl ketone.
Electrocyclization reactions of 1-Aza- and 1-oxapentadienyl and -heptatrienyl cations: Synthesis of pyrrole and furan derivatives
Alickmann, Dirk,Froehlich, Roland,Maulitz, Andreas H.,Wuerthwein, Ernst-Ulrich
, p. 1523 - 1537 (2007/10/03)
Quantum chemical DFT calculations (B3LYP/6-31+G) have been used to gain insight into the conformational and energy properties of the 1-aza- and 1-oxapentadienyl and -heptatrienyl cations 1, 2, 3, and 4. The calculated thermodynamic and kinetic data of the ring-closure reactions giving the cyclic products 5-14 are reported and discussed with respect to the experimental results. Experimentally, synthetic routes to the α,β-unsaturated carbonyl compounds 24 and 27, each with a leaving group in the γ-position, have been developed. These compounds have been investigated with respect to their ability to undergo 1,5-electrocyclization reactions to yield 2,5-disubstituted furans 28 upon heating in the presence of acid, presumably through the intermediate formation of the 1-oxapentadienyl cations 2. From the corresponding imine 29a the pyrrole 30d was obtained after treatment with tetrakis (triphenylphosphane) palladium. In the presence of benzylamine and the Pd° catalyst, the corresponding pyrroles 30a-c were formed from 24 and 27. The homologous α,β,γ,δ-unsaturated carbonyl compounds 31 afforded 2-vinyl-substituted furans 32 upon heating with acid, and the 2-vinyl-substituted pyrroles 34 on treatment with benzylamine and the Pd catalyst. No seven-membered heterocyclic rings were formed. Surprisingly, the α,β-unsaturated carbonyl compounds with two phenyl substituents at the γ-position also provided pyrrole derivatives 40 through a formal dimerization. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Synthesis of naphthalenes using acid-catalyzed ring-opening and recyclization of 3-acetyl-5,5-diaryl-2-methyl-4,5-dihydrofurans. Isolation of intermediates
Kajikawa, Shougo,Nishino, Hiroshi,Kurosawa, Kazu
, p. 3351 - 3354 (2007/10/03)
3-Acetyl-5,5-diaryl-2-methyl-4,5-dihydrofurans were heated in concentrated hydrochloric acid to give the 4-aryl-1-methylnaphthalenes in high yields. The same reaction was carried out in hydrochloric acid diluted with acetonitrile to give the 5,5-diaryl-4-
Formation of tetrahydrofuran derivatives and acetonylation of alkenes using carbon radicals derived from manganese(III) oxidation of diketene
Nishino, Hiroshi,Nguyen, Van-Ha,Yoshinaga, Shinji,Kurosawa, Kazu
, p. 8264 - 8271 (2007/10/03)
Oxidation of a mixture of diketene and a 1,1-diarylethene 1 with manganese(III) acetate dihydrate gave an equilibrium mixture of 5-hydroxy-2-pentanone 2 and a tetrahydrofuran-2-ol, which was subsequently dehydrated in glacial acetic acid to yield 4-penten-2-one 4 in good yield. A similar reaction in the presence of alcohols or amines afforded 2-alkoxy-2-methyltetrahydrofurans 5 or 3-acetyl-2-aminodihydrofurans 9 in moderate yields. Diketene reacted with manganese(III) acetate in the presence of nucleophiles, such as water and alcohols, to give a mixture of unconjugated manganese(III) enolate A and conjugated manganese(III) enolate B. Major products 4 and 5 were formed by the oxidation of the conjugated manganese(III) enolate B. Tetrahydrofurylideneacetates 3 and 7 derived from the unstable unconjugated enolate A were also obtained as minor products. The reaction pathways are discussed.
New Synthetic Routes to Furans and Dihydrofurans from 1-Propargylbenzotriazole
Katritzky, Alan R.,Li, Jianqing,Gordeev, Mikhail F.
, p. 3038 - 3041 (2007/10/02)
Base-assisted cyclizations of 1-propargyl>benzotriazoles, derived from lithiated 1-propargylbenzotriazole (1) and aromatic aldehydes or ketones, gave 2-arylfurans 5 or 1-(5,5-diaryl-2,5-dihydrofuran-2-yl)benzotriazoles 7, respectively, in high yields.Compounds 7 with Grignard reagents yielded trisubstituted 2,5-dihydrofurans 9.
Photochemistry of two diphenyl β,γ-enones and a series of methyl- and phenyl-substituted α-phenyl ketones
Koppes, Margareth J. C. M.,Crabbendam, Astrid M.,Cerfontain, Hans
, p. 676 - 683 (2007/10/02)
The photochemistry of the diphenyl β,γ-enones 2 and 3 and the methyl- and phenyl-substituted α-phenyl ketones 4-9 has been studied, using mainly benzene as solvent.Irradation of 2 with λ 300 nm leads to the 1,3-acyl shift (1,3-AS) product 17, relatively small amounts of the decarbonylation products 15 and 16, and the photo-oxidation products benzophenone (18) and the α,β-unsaturated aldehyde 19.Direct irradation of the 1,3-AS product 17 yields 15, 16, 18 and 19, but no 2.Direct irradation of 3 with λ 350 nm leads mainly to the formation of 1,3-AS products (E)- and (Z)-22, the decarbonylation products (E)- and (Z)-20 and 21 and, in addition, a small amount of the cis-di-?-methane isomer 23.Direct irradation of the substituted α-phenyl ketones 4, 5, 8 and 9 with λ 300 nm leads predominantly to the formation of the radical coupling products 2,3-butanedione and 24-27, respectively, whereas 6 and 7 yield 1,2-diphenyl-1,2-ethanedione and the respective 24 and 25.The acetone-sensitized irradation of 4 leads to 4-phenyl-2-butanone (33) in addition to 2,3-butanedione and 1,2-diphenylethane (24).
Cyclopropanols and the Di-?-methane Rearrangement: Mechanistic and Exploratory Organic Photochemistry
Zimmerman, Howard E.,Nuss, John M.,Tantillo, Anthony W.
, p. 3792 - 3803 (2007/10/02)
The photochemistry of a series of di-?-methane systems, having a hydroxyl group on the methane carbon, was investigated.Both the divinyl and the aryl vinyl versions were studied.In certain cases, an isomeric γ,δ-unsaturated ketone was obtained; the reactant a-b-c-d-e carbon skeletal sequence was permuted to afford the product with the sequence c-a-b-d-e.In two cases intermediate cyclopropanols could be isolated and in all instances evidence was obtained that the bizarre rearrangement resulted from a di-?-methane rearrangement followed by ring opening of the resultant cyclopropanol.Photolysis of the corresponding phenyldimethylsilyl ethers led nicely to the corresponding cyclopropyl ethers in all cases.Tetrabutylammonium fluoride treatment resulted in ring opening.Quantum yields and reaction multiplicites were determined.Direct and sensitized irradiations established both singlet and triplet reactivity.The photochemistry of the cyclopropane products revealed cis-trans isomerization of the silyl ethers and, additionally, ring opening of the cyclopropanols.One of the reactions proved reversible, thus 1,2,2,5,5-pentaphenylpent-4-en-1-one afforded the stereoisomeric 1,2,2-triphenyl-3-cyclopropanols.Single photon counting was employed to obtain the excited singlet lifetime and reaction rate for 1,1,3,3-tetraphenyl-2-propen-1-ol.
Thromboxane A2 Analogues from 8-Oxabicyclooct-6-en-3-ones
Bowers, Kevin G.,Mann, John,Walsh, E. Brian,Howarth, Oliver W.
, p. 1657 - 1666 (2007/10/02)
We describe approaches to thromboxane A2 analogues (3), (4), and (32) which contain 2,6-dioxabicyclooctane and 2,6-dioxatricyclo3,7>nonane ring system.Both were derived from 2-substituted 8-oxabicyclooct-6-en-3-
