作者:Bruno Tse、Charles M. Blazey、Ben Tu、James Balkovec
DOI:10.1021/jo970106l
日期:1997.5.1
The absolute stereochemistry of (-)-galbonolide A (1) was assigned by chemical methods. First, 1 was degraded to diol 3. After selective silylation of the primary alcohol, two independent methods were carried out to determine the chirality at C13. Both established its S-configuration. Using the methodology developed in the total synthesis of (-)-galbonolide B, diols 13(S,S) and 13(S,R) were prepared
(-)-galbonolide A(1)的绝对立体化学是通过化学方法确定的。首先,将1降解为二醇3。在对伯醇进行选择性甲硅烷基化之后,进行了两种独立的方法来确定C13的手性。两者都建立了其S配置。使用在(-)-galbonolide B的全合成中开发的方法,制备了二醇13(S,S)和13(S,R)。将其(R)-MTPA酯14(S,S,R)和14(S,R,R)与降解产物3的类似(R)-MTPA酯进行比较,随后确定了S-手性在C8。为了确定在C4的手性,进行了两种独立的方法。一个涉及比较加蓬内酯B的C4的手性。另一个涉及比较加蓬内酯A 22的降解产物及其合成等效物。两种方法均证实了C4处的S-构型。由于已证实加蓬内酯A和B的四个手性中心中的三个相同,并且由于两个加蓬内酯的(1)H NMR光谱表明其构象非常相似,因此这两个化合物在C2上的构型也应为相同。