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Double annulations of dihydroxy- and diacetoxy-dialkynylbenzenes. An efficient construction of benzodifurans |
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| Authors: | Zhiqiang Liang Shengming Ma Jihong Yu Ruren Xu |
| Institution: | aState Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, PR China bState Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, PR China |
| Abstract: | An efficient synthetic route to construct disubstituted benzodifurans from dihydroxy- or diacetoxy-dialkynylbenzenes utilizing Cs2CO3 or Pd(OAc)2/Cs2CO3 promoted double annulations is described. The scope for the reaction in the presence of a catalytic amount of Pd(OAc)2 is more general. In addition, it was observed that NaOH-promoted reaction of diacetoxy-dialkynylbenzenes may directly afford in THF/MeOH/H2O at 80 °C benzodifurans through hydrolysis and double cyclization in a one-pot manner. However, in most cases, the reaction is less selective affording a mixture of the double cyclization products and monocyclization–hydrolysis products. |
| Keywords: | Benzodifuran Palladium Base Annulation |
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