A General Strategy for the Stereocontrolled Preparation of Diverse 8- and 9-Membered Laurencia-Type Bromoethers
摘要:
A unique procedure to effect a ring-expanding bromoetherification process is described, wherein tetrahydrofurans and tetrahydropyrans are smoothly transformed into 8- and 9-membered bromoethers in a regio- and stereocontrolled manner through the use of BDSB (bromodiethylsulfonium bromopentachloroantimonate). These products resemble the cores of the Laurencia C15 acetogenins. In light of the generality and effectiveness of the approach, this work provides a unique strategy for their laboratory preparation and may implicate a possible biosynthesis pathway.
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。
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.
Novel Approach to the Synthesis of 6-Substituted 5,6-Dihydro-2(2H)-pyranones
作者:Charles Fehr、Jos� Galindo、G�nther Ohloff
DOI:10.1002/hlca.19810640503
日期:1981.7.22
Easily accessible dihydropyrans 9, 10, 12 and 19 are precursors for the synthesis of 6-substituted5,6-dihydro-2 (2H)-pyranones and 6-substituted tetrahydro-2-pyranones. Syntheses of massoia lactone (3), argentilactone (5), tuberolactone (4) and jasmine lactone (2) from acrolein (6), acrolein dimer (7) or glutaraldehyde (16) are described.
Heck arylation of cyclic enol ethers with aryldiazonium salts: regio- and stereoselective synthesis of arylated oxacycles
作者:Bernd Schmidt
DOI:10.1039/b305142k
日期:——
Dihydropyrans and dihydrofurans bearing an aryl substituent in the 2-position are regio- and stereoselectively synthesized by Heck arylation of cyclic enol ethers with aryldiazonium salts.