Partial methylation of (R)-6-hydroxy-3-(3-hydroxypropyl)-7-isopropyl-3,4-dimethylnaphtho[2,3-b]furan-2(3H)-one followed by benzylation afforded the 6-benzyloxy-3-(3-methoxypropyl) derivative, which was converted into the 9-acetyl derivative by the series of reactions; sodium borohydride reduction, acetylation, alkaline hydrolysis, and Jones oxidation. This was oxidized with m-chloroperbenzoic acid to give the 9-acetoxy-5,8-quinone derivative, which was further converted into the 5,6,8,9-tetraacetoxy-3-(3-hydroxypropyl) derivative by hydrogenolysis, reductive acetylation, and demethylation. The tetraacetate in pyridine was treated with o-nitrophenyl selenocyanate in the presence of tributylphosphine and the resulting selenide was oxidized with hydrogen peroxide to give the 3-allyl derivative. This was converted into (+)-coleon A lactone by alkaline hydrolysis and subsequent oxidation. Finally, (+)-coleon A lactone was reduced with sodium borohydride to give (+)-coleon A which was also obtained by lithium aluminium hydride reduction of the 3-allyl derivative.
(R)-6-羟基-3-(3-羟丙基)-7-异丙基-3,4-
二甲基萘[2,3-b]
呋喃-2(3H)-酮的部分甲基化,然后进行苄基化,得到6-苄氧基-3-(
3-甲氧基丙基)衍
生物,通过一系列反应转化为
9-乙酰基衍
生物;
硼氢化钠还原、乙酰化、碱性
水解和琼斯氧化。用间
氯过
苯甲酸氧化得到9-乙酰氧基-5,8-醌衍
生物,通过氢解、还原进一步转化为5,6,8,9-四乙酰氧基-3-(3-羟丙基)衍
生物乙酰化和去甲基化。在
三丁基膦存在下,用邻
硝基苯基
硒氰酸酯处理
吡啶中的
四乙酸酯,并用
过氧化氢氧化所得
硒化物,得到3-烯丙基衍
生物。通过碱性
水解和随后的氧化将其转化为(+)-coleon A内酯。最后,用
硼氢化钠还原(+)-coleon A内酯,得到(+)-coleon A,其也是通过
氢化铝锂还原3-烯丙基衍
生物得到的。