Construction of the Isocopalane Skeleton: Application of a Desulfinylative 1,7-Hydrogen Atom Transfer Strategy
作者:Xiong Xiao、ZhongYu Xu、Qian-Ding Zeng、Xi-Bo Chen、Wen-Hao Ji、Ying Han、PeiYing Wu、Jiangmeng Ren、Bu-Bing Zeng
DOI:10.1002/chem.201500794
日期:2015.6.1
single‐crystal X‐ray diffraction. Both of these chirons are derived from commercially available andrographolide in good yield. Aldehyde 6 is obtained through a novel K2S2O8‐catalyzed aquatic ring‐closing reaction of allylic sodium sulfonate and intramolecular 1,7‐hydrogen atom transfer process. Further mechanistic investigations demonstrate that the 1,7‐hydrogen atom transfer is a free‐radical process, whereby
构造了两个具有吸引力的丁二醛,分别是醛6和氯化物7,它们具有官能化的对映体型三环骨架(ABC环系统),其绝对构型已通过NMR光谱研究,并通过单晶X射线衍射得以证实。这两种Chiron均以良好的产率衍生自市售穿心莲内酯。醛6是通过新型K 2 S 2 O 8获得的烯丙基磺酸钠的催化水生闭环反应和分子内1,7-氢原子转移过程。进一步的机械研究表明,1,7-氢原子转移是一个自由基过程,氢从C18迁移到C17,双18氘标记的同位素实验证明了这一点。还讨论了这两种手性来源的预期应用。