An efficient and general access to 3,4-annulated 2-vinylfurans (type II) is provided by the thermally induced ring transformation of epoxyhexenynes (I). Depending on the substitution pattern the reactions proceed either by heating in solution () or under short-time thermolysis conditions (). The results are consistent with a multistep mechanism involving 1-oxacyclohepta-3,4,6-trienes as central intermediates
通过环
氧己
烯(I)的热诱导环转化,可以有效而普遍地获得3,4-环
氧基
2-乙烯基呋喃(II型)。根据取代方式,反应可通过在溶液中加热()或在短时间热解条件下()进行。结果与涉及1-
氧杂环庚-3,4,6-
三烯作为中心
中间体的多步机理一致。