Efficient Methods for Asymmetric Synthesis Based on Asymmetric Transmission via Sigmatropic Rearrangements

基于西格玛重排不对称传输的高效不对称合成方法

• 批准号: 14550821
• 负责人: NAKAI Takeshi
• 金额: $ 2.56万
• 依托单位: Niigata University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14550821/
• 关键词: Sigmatropic Rearrangement; Carbanion Rearrangement; Wittig Rearrangement; Brook Rearrangement; Asymmetric Transmission; Borneol; Carvenol; Piperitol; 動的速度論的工学

The main results of this 2-year project are as follows :Theme (1)"The Mechanism of the Asymmetric Transmission via [2,3]-Wittig Rearrangement" : A series of experiments using chiral carbanion termini generated from optically active tin compounds provided pieces of evidence in support of the "dynamic kinetic resolution mechanism" for the asymmetric transmission concerned.Theme (2)"Asymmetric Transmission via the [1,4]-Wittig Rearrangement" : First, the carbanion rearrangement of allyl endo-and exo-bornyl ether was found to predominantly undergo the rarely precedented [1,4]-Wittig rearrangement which proceeds in non-stereospecific manner. Second, similar (but at lower temperatures) rearrangements of allyl cis-carvenyl ether and allyl trans-piperityl ether were shown to undergo the [1,4]-Wittig rearrangement predominantly which proceeds with complete retention of configuration. Interestingly enough, the rearrangement of -allyl cis-piperityl ether was found to undergo the [2,3]-Wittig rearrangement exclusively. Thus, the substrate conformation has been revealed to play a key role in determining the periselectivity in these carbanion rearrangements. Third, three convenient procedures have been developed for effecting the [1,4]-retero-Brook rearrangement of allyl silyl ethers to afford the silylated (2)-enol silyl ethers.Theme (3)"Asymmetric Transmission via Sequential Sigmatropic Rearrangements" : the sequential [2,3]-Wittig/oxy-Cope rearrangement of allyl cyclopentenyl ether was investigated. However, no work for evaluating the asymmetric transmission of the Sigmatropic sequence has been made yet.

这个为期2年的项目的主要成果如下：主题(1)“通过[2,3]-Wittig重排的不对称传输机制”：使用由光学活性锡化合物产生的手性碳负离子末端进行的一系列实验支持有关不对称传输的“动态动力学解决机制”的证据。主题（2）“通过[1,4]-维蒂希重排的不对称传输”：首先，发现烯丙基内冰片基醚和外冰片基醚的碳负离子重排主要经历罕见的[1,4]-Wittig重排，该重排以非立体特异性方式进行。其次，烯丙基顺式香芹基醚和烯丙基反式哌啶基醚的类似（但在较低温度下）重排主要经历[1,4]-维蒂希重排，该重排在完全保留构型的情况下进行。有趣的是，发现α-烯丙基顺式胡椒基醚的重排仅发生[2,3]-维蒂希重排。因此，底物构象已被揭示在确定这些碳负离子重排的近选择性中发挥关键作用。第三，已经开发了三种方便的程序用于实现烯丙基甲硅烷基醚的[1,4]-逆布鲁克重排以提供甲硅烷基化的(2)-烯醇甲硅烷基醚。 主题(3)“通过连续西格玛重排的不对称传递”：研究了烯丙基环戊烯基醚的连续[2,3]-Wittig/oxy-Cope重排。然而，尚未开展评估 Sigmatropic 序列的非对称传输的工作。

项目成果

Takahiro Tomoyasu, Katsuhiko Tomooka, Takeshi Nakai: "Asymmetric Synthesis of Enantio-enriched Acyclic a-Amino Alkylstanannes and Rearrangement Behavior of Carbanions Thereof"Tetrahedron Letters. Vol.44. 1239-1242 (2003)

Takahiro Tomoyasu、Katsuhiko Tomooka、Takeshi Nakai：“对映体富集的无环 a-氨基烷基斯坦烷的不对称合成及其碳负离子的重排行为”四面体字母。

Takahiro Tomoyasu, Katsuhiko Tomooka, Takeshi Nakai: "Asymmetric synthesis of enantio-enriched acyclic α-amino alkylstanannes and rearrangement behavior od carbanions thereof"Tetrahedron Letters. Vol.44. 1239-1242 (2003)

Takahiro Tomoyasu、Katsuhiko Tomooka、Takeshi Nakai：“对映体富集的无环 α-氨基烷基斯坦的不对称合成及其碳负离子的重排行为”Tetrahedron Letters Vol.44（2003）。