Introduction of the (−)-Berkelic Acid Side Chain and Assignment of the C-22 Stereochemistry
作者:Xiaoxing Wu、Jingye Zhou、Barry B. Snider
DOI:10.1021/jo901221a
日期:2009.8.21
oxidized and deprotected to complete the synthesis of (−)-berkelic acid and (−)-22-epi-berkelic acid. This synthesis establishes the absolute stereochemistry and assigns the stereochemistry at C-22. A biosynthetic pathway is proposed that is consistent with the known absolute stereochemistry at the quaternary carbon of spiciferone A, spicifernin, and berkelic acid and provides a simple explanation for
醛与三甲基甲硅烷基乙烯酮缩醛的 Kiyooka 羟醛缩合反应和由N -Ts-( S )-缬氨酸制备的恶唑硼烷酮得到四种可能的羟醛加合物中的两种,它们被氧化和脱保护以完成 (-)-berkelic 的合成酸和 (-)-22- epi- berkelic 酸。该合成建立了绝对立体化学并将立体化学指定为 C-22。提出了一种生物合成途径,该途径与已知的 spiciferone A、spicifernin 和 berkelic 酸的季碳上的绝对立体化学一致,并为 spicifernin 和 berkelic 酸的 C-18 和 C-19 的不同立体化学提供了简单的解释。