A new approach to benzofuran synthesis: Lewis acid mediated cycloaddition of benzoquinones with stilbene oxides
作者:Ken Kokubo、Kenji Harada、Eiko Mochizuki、Takumi Oshima
DOI:10.1016/j.tetlet.2009.12.047
日期:2010.2
We report a BF3-mediated novel dehydrative cycloaddition reaction of benzoquinones with stilbene oxides to afford 2,3-diaryl-5-hydroxybenzofurans and 2,3-diaryl-5-hydroxydihydrobenzofurans in good combined yields. No change in the products or the yield is observed when using diphenylacetaldehyde and cis-stilbene oxide instead of trans-stilbene oxides. When stilbene oxide is reacted with hydroquinone
我们报告了BF 3介导的苯醌与氧化lb的新型脱水环加成反应,以良好的合并收率提供了2,3-二芳基-5-羟基苯并呋喃和2,3-二芳基-5-羟基二氢苯并呋喃。当使用二苯乙醛和顺式二苯乙烯氧化物代替反式时,没有观察到产品的变化或收率的变化。-二苯乙烯氧化物。当在相同条件下使氧化苯乙烯与对苯二酚而不是相应的苯醌反应时,可以高产率分离出二氢苯并呋喃。根据这些结果,我们提出以下可能的反应机理:二氧化二锡被转化为a离子(关键中间体),苯醌或同时生成的氢醌经历亲核攻击,随后分子内环化脱水,生成苯并呋喃或二氢苯并呋喃。 , 分别。