- Ozonolyses of 1-Alkyl-Substituted 3-Methylindenes. Remarkable Effects of the Substituent Steric Bulk and the Stereochemistry of the Carbonyl Oxide Intermediates on the Efficiency of Ozonide Formation
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Ozonolyses of 3-methyl- and 3-isopropyl-l-methylindenes (1a,b) in ether gave mainly the corresponding oligomers 3a,b, while in the case of 3-phenyl- and 3-tert-butyl-1-methylindenes (1c,d), the corresponding exo-endo mixtures of ozonides 2c,d were obtaine
- Kawamura, Shin-Ichi,Takeuchi, Rika,Masuyama, Araki,Nojima, Masatomo,McCullough, Kevin J.
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p. 5617 - 5622
(2007/10/03)
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- Cycloaddition between Carbonyl Oxides and Dicarbonyl Compounds: Isolation and Characterization of Novel Polycyclic 1,2,4,6-Tetroxepane Derivatives
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Formaldehyde O-oxide reacts with dicarbonyl compounds to produce mono-ozonides formed by conventional cycloadditions to an aldehyde carbonyl group of the substrate, and/or polycyclic 1,2,4,6-tetroxepane derivatives arising from formal cycloadditions involving both carbonyl groups.Similar reactions between the more highly substituted carbonyl oxides, benzaldehyde and octanal O-oxides, and dicarbonyl compounds yielded the corresponding mono-ozonides as the sole isolable cycloaddition products.In certain favorable cases, mono-ozonides could undergo acid-catalysed intramolecular rearrangement to the corresponding 1,2,4,6-tetroxepanes.X-Ray crystallographic analyses of two 1,2,4,6-tetroxepanes, 6a and 13b, are recorded.
- McCullough, Kevin J.,Sugimoto, Toshiya,Tanaka, Shogo,Kusabayashi, Shigekazu,Nojima, Masatomo
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p. 643 - 652
(2007/10/02)
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- Ozonolysis of 1-Methylindenes. Solvent, Temperature, and Substituent Electronic Effects on the Ozonide Exo/Endo Ratio
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The ozonolyses of 1-methyl-3-aryl-, 1,2-dimethyl-3-aryl-, and 1-methyl-2,3-diarylindenes (1a-e, 4a-e, 7a-e, 7a',b',d') in various solvents at several temperatures have been undertaken.The data revealed the following. (a) The ozonolysis of indenes 1c, 4c,
- Miura, Masahiro,Fujisaka, Tomohiro,Nojima, Masatomo,Kusabayashi, Shigekazu,McCullough, Kevin J.
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p. 1504 - 1509
(2007/10/02)
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- Ozonolysis of a Series of 1-Substituted Indenes. The Substituent Steric Effects on Ozonide Exo/Endo Ratios
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The ozonolysis of a series of disubstituted (1,2 and 1,3) and trisubstituted (1,2,3) indenes 1-28 in carbon tetrachloride at 20 deg C has been investigated.The major product in each case was the corresponding bicyclic ozonide, usually obtained as a mixtur
- Miura, Masahiro,Nojima, Masatomo,Kusabayashi, Shigekazu,McCullough, Kevin J.
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p. 2932 - 2936
(2007/10/02)
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- Acidolysis of Ozonides. An ab Initio Study
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As the model species of the intermediates which may participate in the acidolysis of ozonides, seven species 14-20 have been investigated with the ab initio SCF-MO method at the split-valence 4-31G level.On the basis of both the relative stabilities and the charge distributions of these species, we have attempted to provide insight into the apparently complicated experimental observations.
- Miura, Masahiro,Nagase, Shigeru,Nojima, Masatomo,Kusabayashi, Shigekazu
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p. 2366 - 2370
(2007/10/02)
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- Synthesis, X-ray Analysis, and Acidolysis of exo- and endo-1-Methylindene Ozonides
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Ozonolyses of 2,3-disubstituted 1-methylindenes gave mixtures of the corresponding exo and endo ozonides.The structures of endo-1-methyl-3-phenylindene ozonide (3a) and exo-1-methyl-2,3-diphenylindene ozonide (2b) were determined by the X-ray analysis.Acidolysis of exo- and endo-1-methylindene ozonides 2a-d and 3a-d under several conditions revealed some characteristic features. (a) Antimony pentachloride or chlorosulfonic acid catalyzed the interconversion of the exo-endo ozonide isomers, the ratio in equilibrium being ca. 7:3 for all the pairs. (b) In the reaction of 3-methyl-substituted indene ozonides 2c,d and 3c,d in acetic-d3 acid-d a rapid hydrogen-deuterium exchange on the bridgehead methyl was observed. (c) In methylene chloride or acetic acid the ozonides decomposed very slowly, yielding the mixtures of rearranged products 4 and 5, carboxylic acid 6, and diketone 7; both the rate of decomposition and the product distribution being a marked function of the structure of the ozonides. (d) Methanol accelerated the decomposition of ozonides, the disappearance following pseudo-first-order kinetics.The rate decreased in the order 3a > 2a > 2b > 2c ca. 3c > 3b.This order was significantly different from the order observed in the reaction in acetic acid: 3b > 3c > 2b > 2c > 3a > 2a. (e) Reduction by AlHCl2 gave a mixture of 3,4-dihydro-1H-2-benzopyrans 19 - 22, the composition being significantly varied depending on the stereochemistry of the ozonides. (f) Treatment of 2a or 3a with bis(α-hydroxy-4-methylbenzyl)peroxide (31) gave two stereoisomeric peroxides 32a and 33a in roughly equal amounts.In contrast, the reaction of an exo ozonide 2d with a mixture of p-tolualdehyde and 30percent H2O2 (an equivalent of 31) afforded exclusively the corresponding exo peroxide 32d, while the endo isomer 3d gave predominantly the endo peroxide 33d.
- Miura, Masahiro,Ikegami, Akio,Nojima, Masatomo,Kusabayashi, Shigekazu,McCullough, Kevin J.,Nagase, Shigeru
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p. 2414 - 2426
(2007/10/02)
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