Elucidafion of Origin of"Syn-Effect" and Application to Organic Synthesis

“顺效应”起源的阐明及其在有机合成中的应用

基本信息

批准号：
18550030
负责人：
UKAJI Yutaka
金额：
$ 2.68万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

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.

通过LDA研究了[3-取代（E）-1 -1-丙烯基]对相应2,4-二烯基醇的1,4-释放环开口的立体化学。所得的2,4-二烯基醇的z/e比在丙烯基的3位时随替代物而变化。基于“合成效应”的概念讨论了这种现象，该概念最初是通过σ→π*相互作用合理化的。将胺胺添加到（e）-1-甲基-l，3-丁二烯的核能添加的静脉化学。所产生的slic硫磺酮的z/e比随胺，溶液，温度和浓度而变化。当在较高温度下以低浓度反应二乙胺时，优选获得相应的在空间不利（Z）-4-氨基-2-丁烯基磺基磺基酮。将胺添加到乙基（E）-2,4-苯二烯酸酯中的核直体化学化学化学化学，该酯具有酯基作为共轭电子，而不是p-toluenesulsulfonyl（ts）组，还研究了以实现类似的高（z） - 选择性。 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）-2,4-二烯基1,6-二醇以完全立体选择的方式。顺序的1,4-释环开口 - [1,2] - wittig重排也使用α，α-二甲基烯丙基磺酸来进行相应的（z） - 二烯基醇。