A new synthesis of 13E-ent-crotonadiol and its 13Z-isomer from 6a-acetoxy-14,15-bis-norlabd-8(17)-en13-one is described. A mixture of methyl esters of 13E- and 13Z-6a-acetoxylabd-8(17),13-dien-15-oic and 13E- and 13Z-6a-hydroxylabd-8(17),13-dien-15-oic acids was formed by its reaction with trimethylphosphonoacetate. Mixtures of 13E- and 13Z-6a-hydroxylabd-8(17),13-dien-15-oic acids were formed by hydrolysis of this mixture. These were separated, methylated, and reduced by LiAlH4 to give the pure 13E- and 13Z-crotonadiols in 64 and 16% yields, respectively. The two known syntheses of crotonadiol from (+)-larixol were reproduced. It was shown that they produced only 13E-crotonadiol.
描述了一种从 6a-acetoxy-14,15-bis-norlabd-8(17)-en13-one 合成 13E-ent-crotonadiol 及其 13Z-isomer 的新方法。13E- 和 13Z-6a- 乙酰氧基赖百当-8(17),13-二烯-15-酸和 13E- 和 13Z-6a- 羟基赖百当-8(17),13-二烯-15-酸的甲酯混合物是由其与
三甲基膦酰
乙酸酯反应生成的。13E- 和 13Z-6a-hydroxylabd-8(17),13-dien-15-oic acids 的混合物通过
水解形成。将这些混合物分离、甲基化并用 LiAlH4 还原后,得到纯净的 13E- 和 13Z-
巴豆二醇,产率分别为 64% 和 16%。从 (+)-larixol 中合成
巴豆二醇的两个已知方法被重现。结果表明,它们只生成了 13E-
巴豆二醇。