An efficient synthesis of triptophenolide methyl ether 4 from the readily available abietic acid 3 in nine steps is described and successfully applied to the synthesis of (−)-triptolide 1. The route is of characteristic of low cost, high yield and easy operation. In addition, every reaction in this route has been successfully scaled-up to a 100 g substrate level without loss of yield.

中文翻译：

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有效合成关键的中间体雷公藤酚甲醚用于合成（-）-雷公藤内酯

从九个步骤中容易获得的松香酸3高效合成了雷公藤多酚甲醚4，并已成功应用于（-）-雷公藤内酯1的合成。该路线具有成本低，产量高，易于操作的特点。此外，此路线中的每个反应均已成功扩大规模至100 g底物水平，而没有损失收率。