Penta-l,4-dien

Jeong described desymmetrization of dienynes, such as iV-propargyl-jY-(penta-l,4-dien-3-yl) tosylamides, by the asymmetric Ir(i)-based PK-type reaction. The corresponding vinyl-substituted bicyclo[3,3,0]-octenones were obtained with high diastereoselectivity and enantioselectivity (Equation (36)). ... 

A solution of 19.4 g N-2,4-dimethylphenyl-N -methylformamidine and 0.3 g p-toluenesulphonic acid in 195 ml dry xylene was refluxed under anhydrous conditions for 48 h, causing the evolution of methylamine. The xylene was distilled off under reduced pressure to give l,5-di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triaza-penta-l,4-diene, melting point 88°-89°C (crystallized twice from isopropyl). 

Die von Stobbe und Farber 295) vorgeschlagene tricyclische Struktur 9 fiir das Photodimere des Dimethylesters der 3-Oxo-penta-l,4-dien-l,5-... 

Katsuki-Sharpless desymmetrization of penta-l,4-dien-3-ol gives the monoepoxide 490, which can be converted into l,4-dideoxy-l,4-imino-D-lyxitol 491 (Scheme 13.112) [217]. 

When the cyclopropane homolog 24, with the same 1,1,2,2-tetrabromide array, was treated with zinc, the analogous fragmentation reaction occurred, leading in this case to an 84% yield of 2,4-dimethyl-penta-l,4-diene, 25This is in contradistinction to the reaction of the corresponding tetramesylate 16 with sodio-diethyl malonate (vide supra). 

Nitrogen can be incorporated as an oxime into a different kind of ene reaction that has been explored by Grigg and his group. The ene component now bears no resemblance to a diene one pair of electrons comes from the lone pair on nitrogen and the other from the OH bond of the oxime 140. The enophile is a more conventional enone and the initial product is a nitrone 141. No nitrogen heterocycle is formed in this step, but, if the enophile contains a second alkene, a 1,3-dipolar cycloaddition gives a bicyclic structure. The simplest reagent for this job is the rather unstable divinyl ketone (penta-l,4-dien-3-one, 143). Fortunately this can be released from the dichloroketone 142 with base and distilled with the solvent THF into the reaction mixture.24... 

Diastereoisomeric mixtures of cyclopropanes result from 1,1,5,5-tetraphenylpenta-l,4-dienes 6 with two different substituents on C3. Cyclopropanols and derivatives are also formed in reasonable yields in similar reactions of penta-l,4-dien-3-ols. 

Diphenyl- or l,5-difuran-2-yl-penta-l,4-dien-3-one 463a,b furnished the spiropyrazol-3-ones 464a,b by Michael addition with pyrazol-3-one 62 (99JCEN61) (Scheme 160). 

Dialkyl acetone-1 -dicarboxylates 1 were transformed with DMFDMA by heating in ethanol into dialkyl l,5- is(dimethylamino)-3-oxo-penta-l,4-diene-2,4-dicarboxylates 52 in good yields. They were treated with ammonia, hydrazine, primary aliphatic, aromatic or heterocyclic amines to form dialkyl 1-substituted 4-oxo-l,4-dihydrop5u--idine-3,5-dicarboxylates 53 and 54.1,4-Diaminobenzene reacts with 52 in a 1 2 molar ratio to produce l,4-bis[3,5-fcis(alcoxycarbonyl)-4-oxo-l, 4-dihydropyridin-l-yl]benzene 55 in 57% yield. Hydrazine and mono-substituted hydrazines afforded 1-amino-1,4-dihydro-4-oxop5uidines 54 (00H2033) (Scheme 20). 

The reaction of indole with 1,5-diaryl penta-l,4-dien-3-ones has been examined using both I2 [258] and AICI3 [259] in conjunction with ultrasonic irradiation. Both sets of conditions give mixtures of mono- and h/s-indole adducts. Another catalyst studied for this reaction is RuCla, which at a 2 1 indole ratio gives the bis-(3-indolyl) adducts [260]. 

Molecular Inclusion Compounds of E, -l-[p-Dimethylamino-phenyl]-5-[o-hydroxyphenyl]-penta-l,4-dien-3-one (DHDK) — the Heilbron Complexes ... 

Dibenzalacetone [l,5-diphenyl-l,4-dien-3-one, l,5-(bisphenyl)-penta-l , 4 -diene-3-one] ]538-58-9] M 234.3, m 107-113°, 112°, 120-122°. Purify the ketone by flash chromatography (150 mesh AI2O3 deactivated with 6% v/w H2O) using petroleum ether 40-60°/EtOAc (4/1, v/v), and the yellow solid is reciystallised by... 

Faghihi K, Hajibeygi M, Shabanian M. New photosensitive and optically active organo-sol-uble poly(amide-imide)s from N,N -(bicyclo [2,2,2] oct-7-ene-tetracarboxylic)-bis-l-amino acids and l,5-bis(4-aminophenyl)penta-l,4-dien-3-one synthesis and characterization. J Polym Res 2010 17(3) 379-90. 

Water-soluble calix[n]arenes are powerful receptors for non-polar substrates in aqueous solution. These compounds are promising candidates as carrier molecules for the transport of non-polar substrates through bulk water as well as inverse phase-transfer catalysts, as proven for the Suzuki coupling of iodobenzene with phenyl boronic acid [91]. 1.5-bis(4,4 -bis(perfluorooctyl)penta-l,4-dien-3-one (39) stabilizes palladium 0) nanoparticles (transmission electron microscopy) formed in the reduction of palladium dichloride with methanol. These palladium colloids are soluble in perfluorinated solvents, and they are efficient recoverable catalysts for Suzuki crosscoupling under fluorous biphasic conditions (Equation 69) [92]. 

Polo V, Andres J (2007) Lewis acid and substituent effects on the molecular mechanism for the nazarov reaction of penta-l,4-dien-3-one and derivatives. A topological analysis based on the combined use of electron localization function and catastrophe theory. J Chem Thetny Comput 3 816-823... 

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