由烯丙基硅烷闭环复分解和随后的S E '亲电子脱甲硅烷基化反应(烯丙基硅烷RCM / S E ')构成外显子的策略的发展描述了-亚甲基亚环烷基。它的效用已在替考克二醇和聚二醇的短合成中得到了证明。替卡醇的合成中的关键转变是醛醇加成反应,它一步一步建立了三种立体化学关系,非对映选择性≥10:1,并且在天然产物合成的背景下,外消旋反应伙伴提供了一个立体立体分化/动力学拆分的双重引人入胜的例子。从环戊烯酮开始合成(±)-戊二醇需要5个步骤,总产率为28%;通过该途径对(-)-戊二醇的对映选择性合成的适应性能够确定该萜烯天然产物的绝对构型。在最后的甲硅烷基化步骤中使用氟化物介导的条件可以保留烯烃的位置,提供天然产物(±)-异戊二醇(五个步骤,环戊烯酮的收率为21%)。聚乙二醇的合成显示了RCM可以构建八元环,并具有高度非对映选择性的环氧化/氟化物介导的片段化序列,可用于安装外亚甲基与相邻的带有羟基
Palladium/Acid Relay Catalyzed Tandem Heck Coupling/6‐Endo Cyclization between ortho‐Halogenated Benzoates and Unactivated Terminal Alkenes for the Synthesis of 1‐Isochromanones
We report a unique and expeditiousroute to synthesize 1‐isochromanone derivatives through palladium catalyzed tandem Heck coupling/6‐endo hydroacyloxylation cyclization between readily available ortho‐halogenated benzoates and unactivated alkenes. Various 2‐bromo or 2‐iodo benzoates can be coupled efficiently with a broad range of alkenes to afford functionalized 1‐isochromanones in high yields. Significantly
Ring-Closing Metathesis of Allylsilanes/Electrophilic Desilylation To Prepare <i>exo</i>-Methylidenecycloalkanes. Short Syntheses of Teucladiol and Poitediol
作者:Matthew S. Dowling、Christopher D. Vanderwal
DOI:10.1021/ja906241w
日期:2009.10.28
A general strategy for the synthesis of exo-methylidenecycloalkanes, which are salient features of many terpenoid natural products, is presented. Ring-closing alkene metathesis of allylsilanes provides intermediates that can be protodesilylated with alkene transposition to afford the exocyclic alkene; alternatively, the reactivity of the cyclic allylsilane intermediate can be harnessed to introduce
Effects of sterically remote substituents on .pi.-facial stereoselectivity in additions to methylenecyclohexanes
作者:Carl R. Johnson、Bradley D. Tait、Andrzej S. Cieplak
DOI:10.1021/ja00253a064
日期:1987.9
Etude de diverses reactions (oxymercuration, oxydation, osmylation) de methylene cyclohexanes substitues en C3 par des groupes de differentes electronegativites d'encombrements steriques importants
亚甲基环己烷取代 C3 par des groupes de differentes Electronegativites d'encombrements steriques importants 的不同反应(氧汞化、氧化、渗透)练习曲
Modular access to substituted cyclohexanes with kinetic stereocontrol
biologically active compounds. Although methods for the synthesis of thermodynamically favored, disubstituted cyclohexanes are well established, a reliable and modular protocol for the synthesis of their stereoisomers is still elusive. Herein, we report a general strategy for the modular synthesis of disubstituted cyclohexanes with excellent kinetic stereocontrol from readily accessible substituted methylenecyclohexanes
Construction of the A–B–C Ring of Simplicissin through an Oxidative Dearomatization/Iodination/[3+2] Annulation Cascade
作者:Ziwei Zhang、Zezhong Sun、Jianing Song、Hao Guo、Yunxia Wang、Xiangdong Hu
DOI:10.1021/acs.orglett.3c03464
日期:2023.12.8
analogues. On the basis of the development of an oxidative dearomatization/iodination/[3+2] annulationcascade, a concise synthetic pathway to the A–B–C ring of simplicissin has been successfully established, and the substrate generality of the novel oxidative dearomatization/iodination/[3+2] annulationcascade has been checked.