A Unified Strategy for Enantioselective Total Synthesis of Cladiellin and Briarellin Diterpenes: Total Synthesis of Briarellins E and F and the Putative Structure of Alcyonin and Revision of Its Structure Assignment
作者:Olivier Corminboeuf、Larry E. Overman、Lewis D. Pennington
DOI:10.1021/jo9010156
日期:2009.8.7
Enantioselective total syntheses of briarellin E (12) and briarellin F (13), as well as the structure originally proposed for the cladiellin diterpene alcyonin (10), have been realized. Comparison of the spectral data for synthetic 10, natural alcyonin, cladiellisin (33), and cladiellaperoxide (34), as well as chemical transformations of 10 and natural alcyonin, suggest that the structure of this coral
briarellin E ( 12 ) 和briarellin F ( 13 ) 的对映选择性全合成,以及最初为cladiellin diterpene alcyonin ( 10 )提出的结构,已经实现。合成10、天然 alcyonin、cladiellisin ( 33 ) 和 cladiellaperoxide ( 34 )的光谱数据的比较,以及10和天然 alcyonin 的化学转化,表明这种珊瑚代谢物的结构是烯丙基过氧化物11。此处详述的统一方法可用于访问 C4-脱氧和 C4-氧化的 cladiellins 和 briarellins。这些合成的核心步骤是(Z )-α,β-不饱和醛17与环己二烯二醇18形成中间体16,其中包含六氢异苯并呋喃核和这些海洋二萜的五个立体中心(方案 1)。