Lichtreaktionen mit Carbonsäurederivaten, V. Eliminierung doppelt gebundenen Schwefels durch Bestrahlung: Endioläther aus Thionestern und Isonitrile aus Senfölen. Erzeugung atomaren Schwefels in Lösung

Schmidt, Ulrich; Kabitzke, Karlheinz; Boie, Immo; Osterroht, Christoph

doi:10.1002/cber.19650981207

Cited by 33 publications

(16 citation statements)

References 17 publications

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“…Enol-ethers 1b and 1c were prepared by the coupling of diazofenchane (4b) with thionoesters 3b and 3c (Scheme 2). 12,13 This inverse approach is required because the conventional BK reaction would require the difficult preparation of a methoxy-substituted diazomethane derivative. 19 The Bamford-Stevens method was unsuccessful to convert the corresponding tosylhydrazone to diazofenchane (4b).…”

Section: Resultsmentioning

confidence: 99%

“…6,10,11 The reaction consists of the 1,3-dipolar cycloaddition between a diazo and a thio or selenocarbonyl compound, furnishing the target alkene after two-fold extrusion of nitrogen and sulfur/selenium from D 3 -1,3,4-thia-or selenodiazolines. 9 The synthesis of enol-ethers by the BK method has been scarcely investigated, 12,13 and derivatives bearing the fenchyl group have not yet been described.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Ciscato¹,

Bastos²,

Bartoloni

et al. 2010

J. Braz. Chem. Soc.

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Usando-se a reação de Barton-Kellogg, foram sintetizados um alceno e dois enóis-éteres fenchyl-substituídos, contendo grupos 3-oxifenila como substituintes. O fenchil-alceno aromático tri-substituído 1a foi preparado com rendimento de 53% a partir de tiofenchona e um diazoanisol. A abordagem inversa, baseada no acoplamento entre diazofenchona e tionoésteres aromáticos, foi utilizada para produzir os enóis-éteres 1b e 1c (rendimentos 95 e 75%, respectivamente). Em todos os casos foi obtida uma mistura dos isômeros E e Z; a atribuição e quantificação destes isômeros foram realizadas pela análise dos dados de espectroscopia de RMN assistida por cálculos teóricos (relação E/Z 1a = 0,72, 1b = 2,2, 1c = 1,8). A reação ocorre com baixa estereosseletividade, levando à formação preferencial dos diastereoisômeros das olefinas e enóis-éteres, nos quais o substituinte aromático está localizado ao lado dos dois grupos metila da porção fenchila.The synthesis of one fenchyl-substituted alkene and two enol-ethers, containing 3-oxyphenyl substituents by the Barton-Kellogg reaction is described. The tri-substituted aromatic fenchylalkene 1a was prepared in 53% yield from thiofenchone and a diazoanisole; whereas enol-ethers 1b and 1c were obtained (95 and 75% yield, respectively) using an inverse approach based on diazofenchone and aromatic thionoesters. A mixture of Z and E isomers was obtained in all cases; isomer attribution and quantification has been carried out by analysis of NMR spectroscopic data assisted by theoretical calculations (E/Z ratio: 1a = 0.72, 1b = 2.2, 1c = 1.8). Reaction proceeds with low stereoselectivity leading to the preferential formation of diastereoisomeric olefins and enol-ethers where the aromatic substituent resides at the side of the two fenchyl methyl groups.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Ciscato¹,

Bastos²,

Bartoloni

et al. 2010

J. Braz. Chem. Soc.

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“…Caled for C12H8C1N0: C, 66.22; , 3.70. Found: C, 66.45; H, 3.74. 2-Chloro-2-cyano-4-methyl-3-phenylcyclobutanone (7). CCK cycloaddition to 1.25 equiv of (Z)-1-phenylpropene gave 1.45 g of a light yellow solid.…”

Section: Methodsmentioning

confidence: 99%

“…This was stirred for 2 h at room temperature followed by 3 h at 40 °C. Another 0.11 mL of the alkyne was added and the reaction solution was maintained at 40 °C for 8 h. The solution was concentrated and the resulting 0.36 g of orange crystalline solid was recrystallized from hexanes/diethyl ether to give 0.25 g (69%) of 8 as bright orange plates, mp 144.8-146.0 °C dec; UV (ethanol) 396 (400); IR, 2228,1692, 1612; XH NMR, 7.00 (m, 10), 3.47 (q of d, J = 7.0 Hz, J' = 1.6 Hz, 2), I. 98 (s, 3), 1.07 (t, J = 7.0 Hz, 3); 13C (El), m/e (relative intensity) 363 (M+, 7), 329 (100), 301 (66); MS (Cl), m/e (relative intensity) 364 (M + 1, 13), 330 (100).…”

Section: Methodsmentioning

confidence: 99%

Cyanoketenes. Cycloadditions of chlorocyanoketene to alkynes. Generation of vinylogous cyanoketenes

Fishbein¹,

Moore²

1985

J. Org. Chem.

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Chlorocyanoketene (CCK), an exceptionally reactive electrophilic ketene, has previously been shown to undergo facile cycloadditions to ¡mines,1 formimidates,2 aryl aldehydes,3 sulfurdimides,4 and alkenes.5 Its ability to cycloadd to selected alkynes is reported in this manuscript. Also reported is the observation that the resulting cyclobutenones function as precursors to vinylketenes. Indeed, the 4-chloro-4-cyanocyclobutenones arising from the initial cycloadditions are in equilibrium with their respective

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“…1-3); the induction of the same I reaction under the action of light has been less frequently reported (4)(5)(6). The photolysis of 2,6-diphenyl-4H-pyran-4-thione 1 to give 2 has been described (6) and the mechanism of this reaction has already been subject to some study.…”

mentioning

confidence: 96%

Thione photochemistry: on the formation of dipyranylidenes from pyranthiones

Berenjian¹,

Mayo²

1981

Can. J. Chem.

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The irradiation of the pyranthione 1 has been reinvestigated. The reaction proceeds through the (n,π*) triplet and can be quenched with ferrocene. The reaction can be sensitized with Michler's ketone or triphenylene. The elimination of sulfur from two molecules of 1 to give the dipyranylidene 2 requires, surprisingly, a hydrogen donor solvent, and the quantum yield of product has been found to increase with greater dilution, presumably because of the well-known quenching of triplet thiones by the ground state thione. A mechanism for the formation of 2 is suggested.

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Lichtreaktionen mit Carbonsäurederivaten, V. Eliminierung doppelt gebundenen Schwefels durch Bestrahlung: Endioläther aus Thionestern und Isonitrile aus Senfölen. Erzeugung atomaren Schwefels in Lösung

Cited by 33 publications

References 17 publications

Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Synthesis of some fenchyl-substituted alkenes and enol-ethers containing 3-oxyphenyl substituents by the Barton-Kellogg reaction

Cyanoketenes. Cycloadditions of chlorocyanoketene to alkynes. Generation of vinylogous cyanoketenes

Thione photochemistry: on the formation of dipyranylidenes from pyranthiones

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