- Reaction of Olefins with α-Cyanoacetamide in the Presence of Manganese(III) Acetate
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2-Butenamides and 2-buten-4-olides are formed by the reaction of phenyl or 4-chlorophenyl-substituted olefins with α-cyanoacetamide in the presence of manganese(III) acetate.On the other hand, aryl substituted olefins having electron-donating groups are oxidized under similar reaction conditions to give 1,5-dihydro-2H-pyrrol-2-ones and 3-ethenyl-2-pyrrolidones.All these reactions also produce glycols or ketones which are given by the direct oxidation of these olefins with manganese(III) acetate.The question whether an intermediate carbocation in the oxidation process cyclized on an oxygen or a nitrogen atom can be explained by the hard and soft acids and bases (HSAB) concept.A possible mechanism for the formation of 2-buten-amides and 2-buten-4-olides is proposed.
- Sato, Hidehiko,Nishino, Hiroshi,Kurosawa, Kazu
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p. 1753 - 1760
(2007/10/02)
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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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- Reaction of Olefins with Malonamide in the Presence of Manganese(III) Acetate. Formation of α,β-Unsaturated γ-Lactones and γ-Lactams
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The reaction of olefins with malonamide in the presence of manganese(III) acetate gave 2-buten-4-olides and/or 1H-pyrrol-2(5H)-ones in one-step, short reaction time and moderate yields.The product distribution can be accounted for in terms of the stabilization of the intermediate carbocation in the oxidation process.The synthetic application and limitation, and the oxidation mechanism for the formations of α,β-unsaturated γ-lactones and γ-lactams are discussed.
- Nishino, Hiroshi
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p. 217 - 222
(2007/10/02)
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