In an earlier work we reported that treatment of precocene I with Brönsted and Lewis acids produces its oligomerization, giving dimers, trimers, tetramers, etc. Now, in this article we show that bromination of precocene I with phenyltrimethylammonium tribromide (PTT) blocks its oligomerization giving a dibromo- dimer, which was reduced with tri-n-butyl tin hydride affording the same dimer obtained in the reactions with acid, thus avoiding the oligomerization. Additionally, the oxidations of precocene I with Jones reagent afforded the corresponding 3-hydroxy-4-chromanone, 3,4-chromandione, 3,4-diacid, and two dimers.

中文翻译：

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前十烯I的二聚化

在较早的工作中，我们报道了用Brönsted和Lewis酸处理前十烯I会发生低聚，从而产生二聚体，三聚体，四聚体等。现在，在本文中，我们表明用苯基三甲基铵三溴化铵（PTT）溴化前十烯I会阻止其低聚。得到二溴二聚体，将其用氢化三正丁基锡还原，得到与酸反应得到的相同的二聚体，从而避免了低聚。另外，用琼斯试剂氧化前十烯I，得到相应的3-羟基-4-苯并二氢吡喃酮，3，4-色二酮，3，4-二酸和两个二聚体。