- Metal-Free Synthesis of Selenodihydronaphthalenes by Selenoxide-Mediated Electrophilic Cyclization of Alkynes
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A transition-metal-free, selenium mediated electrophilic cyclization reaction was realized through a one-pot procedure between simple alkynes and triflic anhydride-activated selenoxides to give selenium containing dihydronaphthalene products. This method gave good to very high yields for all products, including selenium-substituted phenanthrene, dihydroquinoline, 2H-chromene, and coumarin, which can be further transformed to other functionalized compounds.
- An, Shaoyu,Li, Pingfan,Zhang, Zhong
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p. 3059 - 3070
(2021/07/22)
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- Stereoselective synthesis of 3-alkylideneoxindoles using tandem indium-mediated carbometallation and palladium-catalyzed cross-coupling reactions
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The first efficient methods for the stereoselective synthesis of various (E)-, (Z)-, and disubstituted 3-alkylideneoxindoles via radical cyclization reactions were investigated using tandem indium-mediated carbometallation and palladium-catalyzed cross-co
- Yanada, Reiko,Obika, Shingo,Kobayashi, Yusuke,Inokuma, Tsubasa,Oyama, Munetaka,Yanada, Kazuo,Takemoto, Yoshiji
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p. 1632 - 1642
(2007/10/03)
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- A simple method for the preparation of substituted phenoxyacrylic acid phenyl esters
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A simple and efficient synthesis of phenoxyacrylic acid phenyl esters via one pot esterification and Michael-type addition starting from propynoic acid and an excess of an appropriate phenol is described.
- Bialecka-Florjanczyk
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p. 4417 - 4424
(2007/10/03)
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- Synthesis of polyalkylphenyl prop-2-ynoates and their flash vacuum pyrolysis to polyalkylcyclohepta[b]furan-2(2H)-ones
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A new method for the smooth and highly efficient preparation of polyalkylated aryl propiolates has been developed. It is based on the formation of the corresponding aryl carbonochloridates (cf Scheme 1 and Table 1) that react with sodium (or lithium) propiolate in THF at 25-65°, with intermediate generation of the mixed anhydrides of the arylcarbonic acids and prop-2-ynoic acid, which then decompose almost quantitatively into CO2 and the aryl propiolates (cf. Scheme 11). This procedure is superior to the transformation of propynoic acid into its difficult-to-handle acid chloride, which is then reacted with sodium (or lithium) arenolates. A number of the polyalkylated aryl propiolates were subjected to flash vacuum pyrolysis (FVP) at 600-650°and 10-2 Torr which led to the formation of the corresponding cyclohepta[b]furan-2(2H)-ones in average yields of 25-45% (cf. Scheme 14). It has further been found in pilot experiments that the polyalkylated cyclohepta[b]furan-2(2H)-ones react with 1-(pyrrolidin-1-yl)cyclohexene in toluene at 120-130°to yield the corresponding 1,2,3,4- tetrahydrobenz[a]azulenes, which become, with the growing number of Me groups at the seven-membered ring, more and more sensitive to oxidative destruction by air (cf. Scheme 15).
- Nagel, Matthias,Hansen, Hans-Juergen
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p. 1022 - 1048
(2007/10/03)
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