The acid catalysed dienone-phenol rearrangement of methyl substituted o-propargyl-cyclohexadienones (scheme 3) was investigated. The rearrangements were carried out in acetic anhydride containing about 10/00 sulfuric acid. Under these conditions acetoxy benzenium ions are formed as intermediates. These then undergo charge-controlled [3s, 4s]- and [1s, 2s]-sigmatropic rearrangements. Thus, the [3s,
研究了甲基取代的邻-炔丙基-环己二酮的酸催化的二烯酮-
苯酚重排(方案3)。的重排在含有约1
乙酸酐进行0 / 00
硫酸。在这些条件下,形成乙酰氧基苯离子作为中间体。然后,它们经历电荷控制的[3 s,4 s ]-和[1 s,2s ]σ重排。因此,[3级小号,4S ] -process通向相应
丙二烯基-
苯酚乙酸盐(形成19,21,23,25,28,30),而[1级小号,2S ] -process收率炔丙基-
苯酚乙酸盐(20,22,24,26,29),分别为(参见方案4)。