Formation and reaction of carbonyl ylides. 1,3-Dipolar cycloaddition of 2-benzopyrylium-4-olates with carbonyl compounds.

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概要

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• Cyclic orthoester type 1,3-dipolar cycloadducts of 1-methoxy-2-benzopyrylium-4-olate with carbonyl compounds were obtained in high yields in the copper(II) acetylacetonate-catalyzed decomposition of <I>o</I>-methoxycarbonyl-α-diazoacetophenone in the presence of carbonyl compounds such as substituted benzaldehydes, acetaldehyde, propionaldehyde, isobutyraldehyde, pivalaldehyde, acetone, methyl ethyl ketone, methyl isopropyl ketone, 1,3-dichloroacetone, substituted acetophenones, benzoyl cyanides, cyclopentanone, cyclohexanone, 1-indanone, 9-fluorenone, anthrone, and anthraquinone. However, methyl <I>t</I>-butyl ketone, benzophenone, and xthanthone gave no adduct. Aldehydes and asymmetric ketones gave endo- and exo-adducts. The regiochemistry and stereochemistry of the adducts of aldehydes were determined on the basis of their coupling constants of methine protons. The reactions of <I>p</I>-methoxyphenyl <I>o</I>-diazoacetylbenzoate also gave similar 1,3-dipolar adducts. When carbonyl compounds of medium reactivity were used as a substrate, 2 : 1-adduct was obtained together with the 1 : 1-adduct. The formation of the 2 : 1-adduct was attributed to the competitive reaction of the corrsponding benzopyrylium-4-olate intermediate toward the carbonyl compounds and 1 : 1-adduct. The regiospecificity of the 1 : 1-cycloaddition was explained according to the frontier orbitals calculated by STO-3G method.

• 公益社団法人 日本化学会の論文

著者

• TOYODA Jiro

  Institute for Molecular Science

• Ibata Toshikazu

  Institute Of Chemistry College Of General Education Osaka University

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• Molecular structure of the exo-Diels-Alder-adduct of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with N-methylmaleimide.
• Synthesis and molecular structure of the 2:1-cycloadduct of 1-methoxy-2-benzopyrylium-4-olate with acenaphthylene.
• The BF3 catalyzed decomposition of diazo compounds in the presence of carbonyl compounds.
• The reaction of diazo ketones in the presence of metal chelates. VIII. The stereochemistry of the 1,3-dipolar cycloaddition of 1-methoxy-2-benzopyrylium-4-olates to ethylenic dipolarophiles.
• Formation and reaction of oxazoles. Synthesis of N-substituted 2-(aminomethyl)oxazoles.
• Aromatic nucleophilic substitution of halobenzenes with amines under high pressure.
• Reaction of diazo ketones in the presence of metal chelates. VII. 1,3-Dipolar cycloaddition of 1-methoxybenzo[c]pyrylium-4-olate with acetylenic dipolarophiles.
• The acid catalyzed decomposition of diazo compounds. I. Synthesis of oxazoles in the BF3 catalyzed reaction of diazo carbonyl compounds with nitriles.
• Formation of 1,3-oxathiole-2-thione and 1,2,4-trithiolane derivatives by the catalytic reaction of .ALPHA.-diazocarbonyl compounds with carbon disulfide.
• Formation and molecular structure of the 2:1-adducts of 1-alkoxy-2-benzopyrylium-4-olates with carbon disulfide.
• The Diels-Alder reactions of 2-alkyl-5-methoxy-4-(p-nitrophenyl)oxazoles with ethylenic, acetylenic, and azo-type dienophiles.
• The Acid-catalyzed Decomposition of α-Diazo β-Hydroxy Ketones
• Formation and reaction of carbonyl ylides. 1,3-Dipolar cycloaddition of 2-benzopyrylium-4-olates with carbonyl compounds.
• The high pressure Diels-Alder reactions of 5-methoxy-2-methyl-4-(p-nitrophenyl)oxazole with ethylenic dienophiles.
• The acid-catalyzed decomposition of diazo carbonyl compounds. II. Synthesis of 2- or 5-heteroatom-substituted oxazoles.

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