Stereoselective total syntheses of (±)-isoagatholactone and (±)-12α-hydroxyspongia-13(16),14-diene, two marine sponge metabolites
作者:Tatsuhiko Nakano、María Isabel Hernández
DOI:10.1039/p19830000135
日期:——
The highly efficient, stereoselective syntheses of (±)-isoagatholactone (1a) and (±)-12α-hydroxyspongia-13(16),14-diene (3e), a fundamental skeleton of spongiadiol (3a) and its related furanoid diterpenes, are described. (±)-Labda-8(20),13-dien-15-oic acid (6), chosen as the starting material, was cyclised to the known tricyclic compound (2b), which after methylation was subjected to photo-oxygenation
高效,立体选择性的合成(±)-异agatholactone(1a)和(±)-12α-hydroxyspongia-13(16),14-diene(3e)(海绵二醇(3a)及其相关呋喃类二萜的基本骨架)的化合物,被描述。将作为起始原料的(±)-Labda-8(20),13-dien-15-oic酸(6)环化成已知的三环化合物(2b),将其甲基化后进行光氧合,得到烯丙基醇(7a)。用在二恶烷中的3.5%硫酸使醇(7a)回流,得到内酯(1b),其用氢化铝锂还原后得到二醇(2g)。随后用柯林斯试剂将该二醇氧化,得到所需化合物(1a)。合成化合物(3e)的关键前体是上面获得的烯丙基醇(7a)。环氧化时,醇(7a)生成环氧化物(13),其通过与二异丙基氨基锂的作用产生了α,β-不饱和γ-内酯(14)。随后用二异丁基氢化铝还原该内酯,得到呋喃(3e)。