Construction of 2,2-Dimethyloxepane Frameworks from Ene-Diols Catalyzed by Metal Catalyst or Brønsted Acid via
Ryo Murakami1, Kakeru Maeda2, Fuyuhiko Inagaki1
1The Faculty of Pharmaceutical Sciences, Kobe Gakuin University.
Abstract:
The synthesis of 2,2-dimethyloxepane frameworks based on the 7-endo-trig cyclization of ene-diol using a catalytic amount of metal catalysts (Au, Ag) or Brønsted acid (TfOH) has been developed. Also, the spiro-type dioxabicyclic products were also derived from the diene-diols. For the condition using metal catalysts, the cyclization selectively reacted between the 1,1,3-trisubstituted alkenes and alcohols to form the 2,2-dimethyloxepane frameworks. On the other hand, the TfOH reacted with not only the 1,1,2-trisubstituted alkene, but also the 1-substituted and 1,2-disubstituted alkenes providing the corresponding cyclic ethers, which is quite different from the conditions of the metal catalysts.
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