作者:Takashi Matsumoto、Shuji Usui
DOI:10.1246/bcsj.55.1599
日期:1982.5
with lead tetraacetate in the presence of iodine to yield 2β,20-epoxy-12-methoxyabieta-8,11,13-triene. Ether cleavage of the 2β,20-epoxy compound with acetyl p-toluenesulfonate, followed by catalytic hydrogenation, afforded 20-acetoxy-12-methoxyabieta-8,11,13-triene (23). This was then converted into methyl 12-methoxyabieta-8,11,13-trien-20-oate (27) via methyl 12-methoxy-7-oxoabieta-8,11,13-trien-20-oate
4-(3-异丙基-4-甲氧基苯乙基)-3,5,5-三甲基-2-环己烯-1-酮酸催化环化得到12-甲氧基松香-8,11,13-三烯-2-酮及其顺式-异构体。两种化合物都进一步转化为 12-methoxyabieta-8,11,13-trien-2β-ol,在碘存在下用四乙酸铅处理得到 2β,20-epoxy-12-methoxyabieta-8,11,13 -三烯。2β,20-环氧化合物与乙酰基对甲苯磺酸酯的醚裂解,然后催化氢化,得到 20-乙酰氧基-12-甲氧基松香-8,11,13-三烯 (23)。然后通过 12-甲氧基-7-oxoabieta-8,11,13-trien-20-oate 甲酯将其转化为 12-methoxyabieta-8,11,13-trien-20-oate (27)。用 AlBr3-EtSH 对 27 进行去甲基化得到三叶草酸,但用 AlCl3-EtSH 27 被部分去甲基化得到三叶草酸甲酯。