- Generation of Thioaldehydes from Sodium Thiosulphate S-Esters (Bunte Salts)
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Treatment of Bunte salts, ZCH2SSO3Na where Z is an electron-withdrawing group, with triethylamine and calcium chloride in the presence of cyclopentadiene or 2,3-dimethylbuta-1,3-diene gives the corresponding cycloadducts of the transient thioaldehydes, ZC
- Kirby, Gordon W.,Lochead, Alistair W.,Sheldrake, Gary N.
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- Continuous Flow Synthesis of 2H-Thiopyrans via thia-Diels–Alder Reactions of Photochemically Generated Thioaldehydes
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Herein, we report a novel protocol for the photochemical generation of thioaldehydes in a continuous flow process which were in situ reacted with electron rich 1,3-butadienes in thia-Diels–Alder reactions. A broad range of 3,6-dihydro-2H-thiopyrans were formed as products in much higher yields and productivities as compared to classical batch processes. Moreover, greatly reduced reaction times and a facile large-scale preparation of products were achieved by fully exploiting the advantages of continuous flow technology.
- Sachse, Florian,Gebauer, Konrad,Schneider, Christoph
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supporting information
p. 64 - 71
(2020/11/30)
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- Synthesis and thermal transformation of stable monocyclic λ4-thiabenzenes
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The stable monocyclic λ4-thiabenzenes 6a-e, which are stabilized with electron-withdrawing substituents such as benzoyl, cyano and alkoxycarbonyl groups, are synthesized in high yields by proton abstraction from the corresponding thiopyranium salts 5a-e with triethylamine in ethanol. The ylidic properties of the λ4-thiabenzenes are established based on spectral and chemical evidence. Thermal decomposition of the λ4-thiabenzenes affords alkyl-rearranged products 7,8, and 9, thienofuran derivatives 10 (from benzoyl-substituted λ4-thiabenzenes), and thiophene derivatives 11. A plausible mechanism for the formation of those products is also discussed.
- Shimizu,Kudo,Kataoka,Hori
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p. 2269 - 2276
(2007/10/03)
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- Novel Type Elimination Reactions of Sulfoxides Bearing Several Heteroaromatics: Trapping of Sulfines with 2,3-Dimethyl-1,3-butadiene
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Previously we reported the novel thioaldehydes generation via thermolyses of phenacyl sulfoxides bearing some heteroaromatics. Thermolysis of sulfoxides (1a,b and 2a-4a) bearing other heterocycles such as thiadiazole, triazole, and tetrazole in the presence of 2,3-dimethyl-1,3-butadiene in dioxane at 100 °C led to the unexpected products 6-substituted-5,6-dihydro-3,4-dimethyl-2H-thiapyran 1-oxide (5a,b). These products were considered to be formed by the Diels-Alder reaction of the diene with the sulfines formed initially by the thermal decomposition of the sulfoxides. The rate acceleration and the improvement of the yield by addition of 1.5 equiv of triethylamine, especially in the case of ethoxycabonylmethyl sulfoxide 1c, was observed. The cis-trans selectivity for sulfine cycloadducts was also studied by NMR spectrometry. The reactions of α-substituted phenacyl sulfoxides 1d-f bearing a phenyl-substituted tetrazolyl group in the presence of the same diene were also studied.
- Morita, Hiroyuki,Takeda, Masahiro,Yoshimura, Toshiaki,Fujii, Takayoshi,Ono, Shin,Shimasaki, Choichiro
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p. 6730 - 6737
(2007/10/03)
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- Formation of Thioaldehyde Intermediates by Thermolysis of Sulfoxides Bearing Some Heteroaromatics
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Thermal reactions of phenacyl sulfoxide bearing heterocycles, such as a 2-benzothiazolyl or N-oxypyridyl group, in the presence of 2,3-dimethyl-1,3-butadiene afforded 6-benzoyl-5,6-dihydro-3,4-dimethyl-2H-thiapyran in good yield. This product is considered to be formed by the Diels-Alder reaction of a diene with thioaldehyde formed initially by the decomposition of sulfoxides.
- Morita, Hiroyuki,Takeda, Masahiro,Fujii, Takayoshi,Yoshimura, Toshiaki,Shimasaki, Choichiro
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p. 9018 - 9023
(2007/10/03)
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- The formation of thiocarbonyl compounds by the thermal decomposition of heteroaryl substituted sulfoxides
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The thermal reaction of phenacyl sulfoxide bearing some heterocycles in the presence of butadiene afforded the thiapyarn derivatives, which is considered to be formed by the Diels Alder reaction of diene with thiocalbonyl compound.
- Takeda, Masahiro,Yoshimura, Toshiaki,Shimasaki, Choichiro,Morita, Hiroyuki
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p. 461 - 462
(2007/10/03)
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- Thiapyran formation via an unexpected thioaldehyde intermediate by the thermal decomposition of phenacyl sulfoxides bearing some heterocycles
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Thermolysis of phenacyl sulfoxide bearing some nitrogen-containing heterocycles in the presence of 2,3-dimethyl-2,3-butadiene led to 6-benzoyl-5,6-dihydro-3,4-dimethyl-2H-thiapyran. This product was considered to be formed by the Diels-Alder reaction of the diene with thioaldehyde formed initially by the thermal decomposition of the sulfoxide.
- Morita, Hiroyuki,Takeda, Masahiro,Kamiyama, Hideo,Hashimoto, Tadaaki,Yoshimura, Toshiaki,Shimasaki, Choichiro,Tsukurimichi, Eiichi
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p. 3739 - 3740
(2007/10/03)
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- Phthalimidosulfenyl chloride. Part 5. Reaction with enolizable carbonyl compounds and synthesis of functionalized thiones
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β-Ketothio derivatives 4, prepared by reaction of phthalimidosulphenyl chloride with enolizable carbonyl compounds, afford, in presence of pyridine, unstable functionalized thiones which can be trapped with 1,3-dienes to give the corresponding cycloadditi
- Capozzi, Giuseppe,Menichetti, Stefano,Nativi, Cristina,Rosi, Alessandro,Valle, Giovanni
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p. 9023 - 9032
(2007/10/02)
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- A novel formation of thiocarbonyl compounds from phosphorus ylides with cyclic polysulfide as the sulfuration reagent
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The reaction of cyclic polysulfides, such as 5H-1,2,3,4-benzotetrathiepin and 6H-1,2,3,4,5-benzopentathiocin as the sulfuration reagent with relatively stable phosphorus ylides affords efficiently thiocarbonyl compounds such as thioaldehydes and thioketon
- Sato,Satoh
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p. 785 - 786
(2007/10/02)
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- Silicon-Assisted Synthesis of Thiocarbonyl Derivatives and Reactivity of Dienophilic Thioaldehydes
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Treatment of bis(trimethylsilyl) sulfide with CoCl2 * 6 H2O in the presence of aldehydes affords the corresponding thiocarbonyl analogues which can be trapped to avoid polymerization.The sulfurization reaction also takes place in the presence of TfOSiMe3, in which case, besides thioaldehydes, thioketones may be obtained in satisfactory yields.When thioaldehydes are generated with the CoCl2 * 6 H2O method the Diels-Alder reaction with cyclohexadiene occurs with very high selectivity in favor of the endo isomer, whereas when the TfOSiMe3-based method is employed, the stereochemistry of the cycloadduct can be conveniently selected toward endo or exo by varying the molar ratio of the sulfurating agent.
- Capperucci, Antonella,Degl'Innocenti, Alessandro,Ricci, Alfredo,Mordini, Alessandro,Reginato, Gianna
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p. 7323 - 7328
(2007/10/02)
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- First isolation of monocyclic thiabenzenes
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Monocyclic thiabenzenes, 1-alkyl-2-aroyl- (or 1-alkyl-2-cyano-) 4,5-dimethyl-thiabenzenes (6) are successfully synthesized by deprotonation of the corresponding thiopyranium salts (5) with triethylamine in ethanol. The ylide structures of 6 are elucidated by spectral and chemical evidence. Thermal reaction of 6 in several solvents provides S-alkyl rearranged products and ring-contracted ones, depending upon solvents used.
- Shimizu,Kudi,Katoaka,Hori
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p. 115 - 118
(2007/10/02)
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- Thioaldehyde Diels-Alder Reactions
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Thioaldehydes containing virtually any α-substitutent can be generated by photofragmentation of phenacyl sulfides.Donor-substituted derivatives are reactive toward electron-rich dienes and give 2 + 4 cycloadducts with regiochemistry corresponding to advan
- Vedejs, E.,Eberlein, T. H.,Mazur, D. J.,McClure, C. K.,Perry, D. A.,et al.
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p. 1556 - 1562
(2007/10/02)
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