- One-pot synthesis of spirofuran and benzocycloalka[1,2-b]furan derivatives using manganese(III)-mediated oxidative radical cyclization
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New spiro[furan-2(3H),1′-(benzocycloalkane)] derivatives were obtained by the oxidation of methylenebenzocycloalkanes with manganese(III) acetate in the presence of 1,3-dicarbonyl compounds. A similar oxidation of the benzocycloalkene derivatives produced the functionalized benzocycloalka[1,2-b] furans in good yields. However, 1-benzyl-3,4-dihydronaphthalene gave both the corresponding spirofuran and benzocydohexa[1,2-b]furan under the same oxidation conditions. The acid-catalyzed ring-opening reaction of the spirofurans and benzocycloalka[1,2-b]furans was also investigated.
- Fujino, Reika,Nishino, Hiroshi
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p. 731 - 740
(2007/10/03)
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- The Facile Synthesis of Dihydrofurans by the Oxidation of Olefins with Tris(2,4-pentanedionato)manganese(III)
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Eleven olefins were oxidized with tris(2,4-pentanedionato)manganese(III) at the reflux temperature to give the corresponding 3-acetyl-2-methyl-4,5-dihydrofurans in good yields.The oxidation of 9-benzylidene-9,10-dihydroanthracene under the same reaction conditions did not produce the corresponding dihydrofuran, but 9--9,10-dihydroxyanthracene.When 1,1-diphenylethene was oxidized at room temperature, 3-acetyl-2-hydroperoxy-2-methyl-5,5-diphenyltetrahydrofuran was obtained in a high yield.The effects of the solvent and the additives on the yield of dihydrofuran, the comparable reactivities of other (2,4-pentanedionato)metal complexes, such as Co(III), Cr(III), Fe(III), and Cu(II), and the reaction mechanism are discussed.
- Nishino, Hiroshi
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p. 1922 - 1927
(2007/10/02)
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