Studies on Macrocyclic Diterpenoids (XVII): Total Synthesis of (-)-Cembrene-A and (+)-3,4-Epoxycembrene-A by Titanium-Induced Carbonyl Coupling Reactions
作者:Xiangjun Yue、Yulin Li
DOI:10.1055/s-1996-4290
日期:1996.6
Efficient total synthesis of (R)-cembrene-A (1) and (+)-3,4-epoxycembrene-A (2), two marine cembranoids, starting from (E)-geranylacetone (6) and (R)-limonene (7) are described. The key steps are the synthesis of olefin 12 from phosphonate 4 and optically active ketone 5 by the modified Wittig olefination, and the titanium-induced intramolecular coupling of oxo aldehyde 3 to afford cembrene-A (1). The pinacol coupling of 3 yielded the diol 13 which was converted into 3,4-epoxycembrene-A (2).
以 (E)-香叶基丙酮 (6) 和 (R)-柠檬烯为起始原料,高效全合成 (R)-西松烯-A (1) 和 (+)-3,4-环氧西松烯-A (2) 这两种海洋西松烯类化合物(7) 进行了描述。关键步骤是通过改进的维蒂希烯化反应从膦酸酯 4 和光学活性酮 5 合成烯烃 12,以及钛诱导的羰基醛 3 分子内偶联得到西柏烯-A (1)。 3 的频哪醇偶联产生二醇 13,将其转化为 3,4-环氧西柏烯-A (2)。