Total synthesis of neolignans, americanin A and isoamericanin A.
作者:HITOSHI TANAKA、ICHIRO KATO、KAZUO ITO
DOI:10.1248/cpb.35.3603
日期:——
The condensation reaction of 3-benzyloxy-4-hydroxybenzaldehyde with 2, 3-epoxy-3- [(3, 4-dimethoxymethoxy) phenyl] -1-propanol, prepared from caffeic acid in four steps, afforded the ether (11) in good yield. Mesylation of 11 followed by treatment with potassium carbonate, provided the epoxide (13), which was converted to the debenzylation product (14) by hydrogenolysis. Compound 14 underwent cyclization with potassium carbonate to yield the trans dioxane derivative (15). Reaction of 15 with the ylide (16) followed by hydrolysis furnished americanin A (1). Isoamericanin A (3) was similarly synthesized from another condensation product (18).
3-苄氧基-4-羟基苯甲醛与 2,3-环氧-3-[(3,4-二甲氧基甲氧基)苯基] -1-丙醇(由咖啡酸分四步制备)发生缩合反应,得到醚(11),收率很高。对 11 进行中间化,然后用碳酸钾处理,得到环氧化物 (13),通过氢解将其转化为去苄基化产物 (14)。化合物 14 与碳酸钾发生环化反应,生成反式二恶烷衍生物(15)。15 与酰亚胺(16)反应,然后水解,得到美洲茄素 A(1)。从另一种缩合产物 (18) 中同样合成了异美利坚素 A (3)。