- Synthesis of benzofulvenes by palladium-catalyzed cyclization of 1,2-dialkynylbenzenes
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A palladium-catalyzed cyclization of enediynes for the synthesis of benzofulvenes 2 in yields of 59-76% was accomplished by treatment of dialkynylbenzenes 1 with 5 mol% of PdX2 and 3 equiv. of CuX 2 in acetonitrile at 60 °C for 2 h.
- Lee, Chia-Ying,Wu, Ming-Jung
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- Fulvenes from Enediynes: Regioselective Electrophilic Domino and Tandem Cyclizations of Enynes and Oligoynes
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Complementary products: the electrophilic cyclizations of ortho-benzooligoynes upon bromination give benzopentafulvenes with orthogonal, peripheral phenyl groups. In contrast, the thermal cyclizations of the same starting materials give naphthalene deriva
- Schreiner, Peter R.,Prall, Matthias,Lutz, Volker
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- Electrophilic cyclizations of 2,3-dialkynylquinoxalines and 1, 2-dialkynylbenzenes: A comparative study
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The reactivity of 2,3-dialkynylquinoxalines towards electrophiles (Br 2, I2, ICI, NBS, HBr) has been studied. All tested reactions, except one with HBr, start with the addition of an electrophile to the carbon-carbon triple bond that promotes further 5-exo-dig carbocyclization ultimately yielding a mixture of stereoisomeric cyclopenta[b]quinoxaline derivatives. The nature of substituents on the C=C bonds of the starting molecule influence the stereochemical result of the reaction. The ratio of isomeric cyclization products also depends on the electrophile used. ortho-Dialkynylbenzenes and ortho-dialkynylquinoxalines demonstrate rather similar reactivity towards halogen electrophiles, but differ in their reactions with hydrobromic acid, which is caused by the basic nature of the aza group of the quinoxaline substrate.
- Gulevskaya, Anna V.,Lazarevich, Roman Yu,Pozharskii, Alexander F.
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p. 910 - 917
(2013/07/05)
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