tandem ring-closingmetathesis (RCM) double-bond isomerization reaction is described in this paper. The utility of this method for the efficient syntheses of five-, six-, and seven-membered cyclic enol ethers is demonstrated. It relies on the conversion of a metathesis-active rutheniumcarbene species to an isomerization-active ruthenium−hydride species in situ. This conversion is achieved by using various
本文描述了一种新型的钌催化串联闭环复分解(RCM)双键异构化反应。证明了该方法对五元,六元和七元环状烯醇醚的有效合成的效用。它依赖于易位活性钌卡宾物质到原位异构化活性钌氢化物物质的转化。通过使用各种添加剂可以实现这种转化。讨论了不同方案的范围和局限性,并基于31 P和1 H NMR光谱学研究提出了一些机械方面的考虑。
Synthesis of conjugated γ- and δ-lactones from aldehydes and ketones via a vinylation(allylation)-ring closing metathesis–oxidation sequence
作者:J.Alberto Marco、Miguel Carda、Santiago Rodrı́guez、Encarnación Castillo、Marı́a N. Kneeteman
DOI:10.1016/s0040-4020(03)00584-2
日期:2003.6
aldehydes and ketones followed by O-allylation of the obtained carbinols gave the corresponding allyl or homoallyl ethers, respectively. Ring-closing metathesis of these compounds afforded in many cases cyclic ethers (dihydrofurans and dihydropyrans, respectively) bearing disubstituted and trisubstituted CC bonds. These were then subjected to allylic oxidation to yield conjugated γ- and δ-lactones. Reasons
In situ conversion of a Ru metathesis catalyst to an isomerization catalystElectronic supplementary information (ESI) available: representative experimental procedure and analytical data for products 3. See http://www.rsc.org/suppdata/cc/b4/b400229f/
作者:Bernd Schmidt
DOI:10.1039/b400229f
日期:——
Addition of alcohols and substoichiometric amounts of a base to a metathesis reaction induces conversion of the metathesis-active carbene catalyst to an isomerization-active hydride species.
Tandem Isomerization/Claisen Rearrangement of Diallyl- and Allylhomoallylethers: In Situ Conversion of Grubbs’ Catalyst to a Ru-H Species
作者:Bernd Schmidt
DOI:10.1055/s-2004-829068
日期:——
allylhomoallylethers do not undergo the expected ring closing metathesis reaction if ethyl vinyl ether is added to the reaction mixture. Instead, upon heating, a selective isomerization of the substrates to allyl vinyl ethers is induced. These then undergo a Claisen rearrangement to produce pent-4-enals.