The syntheses of several 10β-hydroxyfuranoeremophilane derivatives, (±)-10β-hydroxyfuranoeremophilane-3, 6-dione (3), (±)-10β-hydroxyfuranoeremophilan-6-one (4), and (±)-10β-hydroxy-6β-isobutyryloxyfuranoeremophilan-9-one (5), are described. The key step in these syntheses is the angular hydroxylation of 10βH-furanoeremophilane-6, 9-dione (6) using benzeneseleninic anhydride. Reduction of the 10β-hydroxy-6, 9-dione (7) with NaBH4 or ZnNH4OH gave the 9α- or 9β-hydroxy compounds (9a and 10), respectively. The stereochemistries of the diols (9a and 10) were confirmed by the chemical conversion of 9a to the known compound 17. Treatment of 9a and 10 with methanesulfonyl chloride-Et3N afforded the 9β, 10β-epoxide (18). Ring-opening of 18 with NaBH4 gave the 10β-hydroxy compound (21). Deacetalization of 21 with aq. acetic acid afforded (±)-3. Desulfurization of the 3, 3-dithioacetal (24) which was derived from 21 with Raney Ni gave (±)-4. The enone (27a) was treated with isobutyric anhydride followed by catalytic reduction to afford 28b as a major product. Hydroxylation of 28 with benzeneseleninic anhydride in the presence of NaH in chlorobenzene afforded the 10β- and 10α-hydroxy compounds (29a and 29b). Desulfurization of the 3, 3-dithioacetal of 30a which was derived from 29a with Raney Ni gave (±)-5.
几种10β-羟基
呋喃埃莫
菲烷衍
生物、(±)-10β-羟基
呋喃埃莫
菲烷-3、6-二酮(3)、(±)-10β-羟基
呋喃埃莫
菲兰-6-酮(4)和(±)-10β-羟基-的合成描述了 6β-异丁酰氧基
呋喃埃莫
菲兰-9-酮 (5)。这些合成的关键步骤是使用苯
硒酸酐对 10βH-furanoeremophilane-6, 9-dione (6) 进行角羟基化。用NaBH4或ZnNH4OH还原10β-羟基-6, 9-二酮(7),分别得到9α-或9β-羟基化合物(9a和10)。通过将 9a
化学转化为已知化合物 17,证实了二醇(9a 和 10)的立体
化学。用甲
磺酰氯-Et3N 处理 9a 和 10,得到 9β, 10β-
环氧化物 (18)。用NaBH4将18开环得到10β-羟基化合物(21)。 21 用
水溶液脱
缩醛化。
乙酸提供(±)-3。用雷尼
镍将衍生自21的3,3-二
硫缩醛(24)脱
硫得到(±)-4。用
异丁酸酐处理烯酮(27a),然后催化还原,得到主要产物28b。在 NaH 存在下,在
氯苯中用苯
硒酸酐对 28 进行羟基化,得到 10β-和 10α-羟基化合物(29a 和 29b)。衍生自29a的30a的3, 3-二
硫缩醛用Raney Ni脱
硫得到(±)-5。