• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Stereoselective Synthesis of Highly Enantioenriched(E)-Allylsilanes by Palladium-Catalyzed Intramolecular Bis-Silylation:1,3-Chirality Transfer and Enantioenrichment via Dimer Formation
【24h】

Stereoselective Synthesis of Highly Enantioenriched(E)-Allylsilanes by Palladium-Catalyzed Intramolecular Bis-Silylation:1,3-Chirality Transfer and Enantioenrichment via Dimer Formation

机译：钯催化的分子内双甲硅烷基化立体选择性合成高对映体（E）-烯丙基硅烷：1,3-手性转移和二聚体形成对映体

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Highly enantioenriched(E)-allylsilanes have been synthesized from optically active allylic alcohols on the basis of Pd-catalyzed intramolecular bis-silylation followed by highly stereo-specific Si-O elimination reactions.The method involves three steps:1)O-disilanylation of the allylic alcohols with chlorodisilanes,2)intramolecular bis-silylation in the presence of a 1,1,3,3-tetramethylbutyl isocyanide/[Pd-(acac)_2](acac=acetylacetonate)catalyst at 110deg C,and 3)treatment of the reaction mixture with organolithium reagents.The overall transformation proceeds with nearly complete conservation of the enantiopurity of the starting allyl alcohols by transposition of the C=C bond.For instance,(R)-(E)-3-decen-2-ol(99.6-99.7 % ee)produced (5)-(E)-4-(organosilyl)-2-decene of 98.8-99.4% ee for a variety of silyl groups,including Me_3Si,Me_2PhSi,tBu-Me_2Si,Et_3Si,and iPr_3Si.In the bis-silylation step,the initially formed trans-1,2-oxasiletanes immediately dimerize to stereoselectively give l,5-dioxa-2,6-disilacyclooctanes,which are isolated in high yield by carrying out the reaction at 70 deg C.The eight-membered ring compounds undergo thermal extrusion of(E)-allylsilanes in high yield at 110deg C,along with formation of 1,3-dioxa-2,5-disilacyclohexane derivatives.These in turn undergo a Peterson-type elimination by treatment with nucleo-philes such as BuLi and PhLi to give the(E)-allylsilanes.All of the steps involved in the sequence proceed with extremely high stereoselectivity and stereospecificity,leading to almost complete 1,3-chirality transfer through the overall transformation.The dimeri-zation step,which forms diastereomeric intermediates,allows the synthesis of a highly enantioenriched allylsilane(99.4% ee)from an optically active allylic alcohol with lower enantiopurity(79.2% ee)by enrichment of enantiopurity.A general method for the determination of the enantiomeric excesses of(E)-allylsilanes is also described in detail.
机译：在Pd催化的分子内双甲硅烷基化反应之后，通过高度立体特异性的Si-O消除反应，由旋光性烯丙醇合成了高度对映体富集的（E）-烯丙基硅烷，该方法涉及三个步骤：1）O-二甲硅烷基化2，在1,1,3,3-四甲基丁基异氰化物/ [Pd-（acac）_2]（acac =乙酰丙酮）催化剂存在下于110℃进行分子间双甲硅烷基化，以及3）处理（R）-（E）-3-decen-2-例如，（R）-（E）-3-decen-2- ol（99.6-99.7％ee）产生了多种甲硅烷基，包括Me_3Si，Me_2PhSi，tBu-Me_2Si，Et_3Si，（5）-（E）-4-（有机甲硅烷基）-2-癸烯，其硅含量为98.8-99.4％ee在双甲硅烷基化步骤中，最初形成的反式1,2-氧杂环丁烷会立即二聚以立体选择性生成l，5 -dioxa-2,6-disilacyclooctanes，通过在70℃下进行反应高产率地分离。八元环化合物在110℃下高产率地进行（E）-烯丙基硅烷的热挤出，并形成1,3-二氧杂2,5-二硅环己烷衍生物，然后通过用亲核试剂如BuLi和PhLi处理得到Peterson型消除，得到（E）-烯丙基硅烷。该序列以极高的立体选择性和立体专一性进行，从而通过整个转化过程几乎完成了1,3-手性转移。二聚化步骤形成了非对映异构体中间体，从而可以从苯甲酸酯合成高对映体的烯丙基硅烷（99.4％ee）。通过富集对映体纯度降低对映体纯度（79.2％ee）的旋光烯丙基醇。还详细介绍了测定（E）-烯丙基硅烷对映体过量的一般方法。

著录项

相似文献

  • 外文文献
  • 中文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号