The first total synthesis of kwakhurin, a characteristic component of a rejuvenating plant, “kwao keur”: toward an efficient synthetic route to phytoestrogenic isoflavones
作者:Fumihiro Ito、Misako Iwasaki、Toshiko Watanabe、Tsutomu Ishikawa、Yoshihiro Higuchi
DOI:10.1039/b414955f
日期:——
A convergent synthesis of kwakhurin (5), a characteristic estrogen-like isoflavone of Pueraria mirifica(Leguminosae), is described. Isoflavone skeleton 31 was constructed by Suzuki-Miyaura coupling of 3-bromochromone 26 (AC-ring) and arylboronic acid 30 (B-ring) in the presence of TBAB as an additive. Microwave-assisted coupling was also examined, but did not improve the yield. Baeyer-Villiger oxidation
描述了川w(5)的会聚合成,川w(5)是一种葛根的特征性雌激素样异黄酮。异黄酮骨架31是在TBAB作为添加剂的情况下,通过3-溴色酮26(AC环)和芳基硼酸30(B环)的Suzuki-Miyaura偶联反应构建的。还检查了微波辅助耦合,但没有提高产量。Baeyer-Villiger氧化,然后进行炔丙基化和还原,得到1,1-二甲基烯丙基醚37。通过在N,N-二乙基苯胺中37位的克莱森重排,以高收率获得了6'-Prenylisoflavone 34。另一方面,异戊二烯基醚33与粘土的1,3-重排使34的收率差。连续的34甲基化和脱保护,从2,4-二羟基苯甲醛(23)的总产率中,以12%的总收率获得了目标川葵素(5)。