Concise Syntheses of (−)-Galanthamine and (±)-Codeine via Intramolecular Alkylation of a Phenol Derivative
作者:Philip Magnus、Neeraj Sane、Benjamin P. Fauber、Vince Lynch
DOI:10.1021/ja9085534
日期:2009.11.11
Suzuki coupling of 7 to 8 gave the biphenyl derivative 9. Reaction of 9 with ethyl vinyl ether/bromine/base gave 10, which on treatment with CsF/DMF at 130 degrees C resulted in the cross-conjugated 2,5-cyclohexadienone 6. Acid hydrolysis of 6 gave 11, which was reductively aminated to give (+/-)-narwedine 2. Since 2 has been converted into (-)-galanthamine 1 in two steps, this synthesis proceeds in
7 到 8 的 Suzuki 偶联得到联苯衍生物 9。9 与乙基乙烯基醚/溴/碱反应得到 10,在 130 摄氏度下用 CsF/DMF 处理得到交叉共轭的 2,5-环己二烯酮 6。 6 的酸水解得到 11,将其还原胺化得到 (+/-)-narwedine 2。由于 2 分两步转化为 (-)-galanthamine 1,因此该合成分八步进行,总产率为 63 %。用硝基甲烷/碱处理交叉共轭的环己二烯酮 6 得到 12,将其还原为 13。将 13 中的硝基还原为胺,然后在酸性条件下还原胺化,得到可待因骨架 15。 15 转化为 (+/-)-可待因通过先前未知的 α-环氧化物衍生物 18 进行。