derivatives (18, 26, and 27). Intramolecular cyclization of 18 and 26 with anhydrous aluminium chloride followed by demethylation with boron tribromide gave (+)-ferruginol and (+)-sempervirol. The similar cyclization of 27 gave (+)-13-methoxypodocarpa-8, 11, 13-triene. This was reduced with lithium in liquid ammonia in the presence of ethanol and then treated with dilute hydrochloric acid to give (+)-podo
(R)-(-)-α-环
柠檬醛与(3-异丙基-4-甲氧基苄基)-、(4-异丙基-3-甲氧基苄基)-和(3-甲氧基苄基)三苯基
氯化
鏻的Wittig反应得到
苯乙烯基衍
生物其部分氢化成相应的二氢衍
生物(18、26和27)。18 和 26 用无
水氯化铝分子内环化,然后用
三溴化硼去甲基化得到 (+)-ferruginol 和 (+)-sempervirol。27 的类似环化得到 (+)-13-甲氧基podocarpa-8, 11, 13-triene。在
乙醇存在下用液
氨中的
锂将其还原,然后用稀
盐酸处理得到 (+)-podocarpa-8(14)-en-13-one,这是一种用于天然二萜合成的通用中间体。