Angelmarin (1), a novel anti-cancer agent, was efficiently synthesized through a highly enantioselective epoxidation and a copper cyanide-mediated esterification of the hindered alcohol as the key steps in 53% overall yield.
Enantioselective total synthesis of (–)-heliannuol A
作者:Hidetoshi Kishuku、Mitsuru Shindo、Kozo Shishido
DOI:10.1039/b211227b
日期:2003.1.23
An efficient and enantiocontrolled totalsynthesis of (-)-heliannuol A has been accomplished by employing ring closing metathesis and sequential diastereoselective epoxidation and regioselective reductive cleavage of the epoxide ring.
Selective C−S Bond Formation via Fe-Catalyzed Allylic Substitution
作者:Markus Jegelka、Bernd Plietker
DOI:10.1021/ol901297s
日期:2009.8.6
In contrast to the formation of C−O and C−N bonds it was only recently that the selective C−Sbondformation by means of transition metal complexes moved more into the center of research. This is somewhat surprising given the fact that the sulfur atom in a functional group can possess different oxygenation levels which correspond to different chemical properties and reaction portfolios. Herein we wish
new approach has been developed for the synthesis of 8-substituted 2H-chromenes, featuring a novel cascade aromatic Claisen rearrangement/o-quinone methide formation/6π-electrocyclization. This new method was demonstrated with 28 examples tolerating different substitutions at alkenes, allylic and aromatic ring and with total syntheses of three 2H-chromene natural products.
Redox-Active Triazolium-Derived Ligands in Nucleophilic Fe-Catalysis - Reactivity Profile and Development of a Regioselective<i>O</i>-Allylation
作者:Johannes E. M. N. Klein、Michael S. Holzwarth、Stephan Hohloch、Biprajit Sarkar、Bernd Plietker
DOI:10.1002/ejoc.201300902
日期:2013.10
Triazolium-derived N-heterocyclic carbene (aNHC) ligands, which are readily accessible by deprotonation of the corresponding triazolium salts, proved to be versatile ligands in diverse allylic substitution reactions. The corresponding triazolium salts are formed from azides and alkynes through the application of 1,3-dipolar cycloaddition and N-alkylation reactions. The unique property of these ligands
三唑鎓衍生的 N-杂环卡宾 (aNHC) 配体通过相应三唑鎓盐的去质子化很容易获得,被证明是各种烯丙基取代反应中的通用配体。相应的三唑鎓盐是由叠氮化物和炔烃通过 1,3-偶极环加成和 N-烷基化反应形成的。这些配体的独特性质是在其释放形式时是两性离子的,并作为强氧化还原活性 σ-供体配体。凭借这些特性,这些配体能够开发出前所未有的 Fe 催化的烯丙基碳酸酯区域选择性芳氧基化。