| Budget Amount *help |
¥4,190,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Research Abstract |
Stereochemistry of the 1,4-eliminative ring opening of [3-substituted (E) -1-propenyl]oxiranes to the corresponding 2,4-dienyl alcohols by LDA was investigated. The Z/E ratios of the resulting 2, 4-dienyl alcohols varied with the substituents at 3-position of the propenyl group. This phenomenon was discussed based on the concept of a "syn-effect," which is most primarily rationalized by a σ→π* interaction.
Stereochemistry of nucleophilic addition of amines to (E) -1-tosyl-l,3-butadiene was investigated. The Z/E ratios of the resulting allylic sulfones varied with amines, solvents, temperature, and concentration. When diethylamine was reacted in low concentration at higher temperature, the corresponding sterically unfavorable (Z) -4-amino-2-butenyl sulfone was preferentially obtained. Stereochemistry of nucleophilic addition of amines to ethyl (E)-2,4-pentadienoate, which possesses an ester group as a conjugated electron-withdrawing group instead of p-toluenesulfonyl(Ts) group, was also investigated to realize similar high (Z)-selectivity. The predominant formation of (Z)-isomers in both cases was rationalized by a "syn-effect," which might be mainly due to n/σ→π* interaction and/or 6r-electron homoaromaticity.
In the case of δ-benzyloxy substituted vinyloxiranes, [1,2]-Wittig rearrangement proceeded following the initial 1,4-eliminative ring opening to give a (E,Z) -2,4-dienyl 1,6-diols in a completely stereoselective manner. The sequential 1,4-eliminative ring opening-[1,2]-Wittig rearrangement also proceeded using α, α-dimethyl allylic sulfones to give the corresponding (Z)-dienyl alcohols.
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