Allylation with substituted vinylthionium ions from SnCl4 ionisation of 1,3- and 3,3-bis(alkyl/phenylthio) propenes
作者:Roger Hunter、Joseph P. Michael、Daryl S. Walter
DOI:10.1016/s0040-4020(01)85514-9
日期:——
α- and γ-substituted vinylthionium ions from SnCl4 ionisation of a range of substituted 1,3- and 3,3-bis (alkyl/phenylthio) propenes allylate enol allyl ethers in good yield. Levels of regioselectivity are sterically dependent and in the case of methyl as γ-substituent may be controlled by the steric bulk of the sulfur substituent. As with the Pummerer methodology, γ-addition generally gave (E)-vinyl
SnCl 4中的α和γ取代的乙烯基硫鎓离子一系列取代的1,3-和3,3-双(烷基/苯硫基)丙烯进行电离,可以高收率烯丙基烯醇烯丙基醚。区域选择性的水平是空间依赖性的,并且在甲基作为γ-取代基的情况下,可以通过硫取代基的空间体积来控制。与Pummerer方法一样,γ加成通常会生成(E)-乙烯基硫化物,专门暗示“游离”乙烯基硫鎓离子的中间体。在适当的情况下,可以将烯丙基化产物水解并环化为罗宾逊环化产物,脱硫为烯烃或消除为二烯。烯丙基三甲基硅烷和吲哚也以高收率被烯丙基化。具有γ-苯硫基或甲氧基的乙烯基硫鎓离子也经历反应。4。提出了机械原理。该研究以五次硝化序列结束,该序列涉及分子内捕获由该方法产生的乙烯基硫鎓离子。