1999 Fiscal Year Final Research Report Summary
Oxidation with Hypervalent Peroxyiodinanes
| Project/Area Number |
09470485
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemical pharmacy
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| Research Institution | Tokushima University |
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Principal Investigator |
OCHIAI Masahito Tokushima University, Pharmaceutical Sciences, Professor, 薬学部, 教授 (50127065)
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| Co-Investigator(Kenkyū-buntansha) |
SUEDA Takuya Tokushima University, Pharmaceutical Sciences, Instructor, 薬学部, 助手 (40260682)
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| Project Period (FY) |
1997 – 1999
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| Keywords | hypervalent compound / organoiodine / oxidation / benzyl ether / amine / sulfide / phenol / radical |
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| Research Abstract |
(tert-Butylperoxy) iodanes were found to be a useful oxidizing reagent in organic synthesis.
1) They oxidizes benzyl and allyl ethers to the esters at room temperature in the presence of alkali metal carbonates via a radical process. Because this reaction is compatible with other protecting groups such as MOM, THP, and TBDMS ethers, and acetoxy groups, and because esters are readily hydrolyzed under basic conditions, this method provides a convenient and effective alternative to the usual reductive deprotection of benzyl and allyl ethers.
2) Oxidation of sulfides with the (tert-butylperoxy) iodane in acetonitrile-water or in dichloromethane, yielding sulfoxides in high yields. Substituent effects were examined for the oxidation of thioanisoles in acetonitrile-water in the presence and the absence of BF3・Et20 as well as effects of a free-radical scavenger, galvinoxyl.
3) Reaction of secondary amines with (tert-butylperoxy) iodane undergoes dehydrogenation to afford imines in the presence of K2CO3, while oxidation of tertiary amines without base produces tert-butylperoxyamino acetals.
4) (tert-butylperoxy) iodane undergoes oxidation of the methlene groups α to the nitrogen atom of amides (or carbamates) yielding imides or tert-butylperoxyamide acetals, depending on the reaction conditions. A proposed mechanism involves generation of carbon-centered radicals α to the nitrogen atom.
5) Oxidation of 4-alkylphenols by (tert-butylperoxy) iodane in the presence of tert-butylhydroperoxide affords selectively 4-(tert-butylperoxy)-2,5-cyclohexadien-1-ones in good yields. Evidence for the involvement of free-radicals was obtained.
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