- High turnover numbers for the catalytic selective epoxidation of alkenes with 1 atm of molecular oxygen
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The diiron-substituted silicotungstate γ-SiW10{Fe3+(OH2}2O 386- (schematically shown) is an effective catalyst for the oxygenation of alkenes in homogeneous reaction media with 1 atm of molecular oxygen. For example, a selectivity for cyclooctene oxide of 98% and a turnover number of 10000 were achieved in the epoxidation of cyclooctene. The catalyst is stable under the reaction conditions, and its ability to use molecular oxygen raises the prospect of using it in industrial epoxidation processes.
- Nishiyama, Yoshiyuki,Nakagawa, Yoshinao,Mizuno, Noritaka
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p. 3639 - 3641
(2007/10/03)
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- Photo-cleavage of carbon-carbon bond of α-iodocycloalkanones giving ω,ω-dialkoxyalkanoic ester in alcohol
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The irradiation at λ > 300 nm of α-iodocycloalkanones with a high- pressure mercury lamp in alcohols containing a small amount of water afforded the corresponding ω,ω-dialkoxyalkanoic ester (65-88%) by photochemical cleavage of the C(I)-C=O bond at room temperature. In the case of a commercial fluorescent lamp as the irradiating light source, photochemical ring-opening products were also obtained. The irradiation of 2α-iodo-5α- and 4β-iodo-5β-cholestan-3-ones in methanol gave methyl 2,2-dimethoxy-2,3- seco-5α-cholestan-3-oate and methyl 4,4-dimethoxy-3,4-seco-5β-cholestan-3- oate in 78 and 62% yields, respectively. The photochemical behavior of the cleavage reaction of α-iodocycloalkanones is also discussed on the basis of 2-hydroxycycloalkanone as an intermediate.
- Ji, Shun-Jun,Horiuchi, C. Akira
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p. 1645 - 1652
(2007/10/03)
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- Synthesis of α,β-unsaturated ketone from α-iodo ketone using photoirradiation
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Irradiation of α-iodo ketone in hexane under a nitrogen atmosphere with a high-pressure mercury lamp (λ>300nm) at room temperature afforded the corresponding α,β-unsaturated ketones in good yield. This reaction affords a new, clean and convenient synthetic method for the α,β-unsaturated ketone.
- Ji, Shun-Jun,Takahashi, Eiji,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
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p. 9263 - 9266
(2007/10/03)
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