Markwell-Heys Adrian W, George Jonathan H
Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia.
Org Biomol Chem. 2016 Jun 28;14(24):5546-9. doi: 10.1039/c6ob00171h. Epub 2016 Feb 22.
The efficient conversion of siphonodictyal B into the spirocyclic natural products corallidictyals A-D has been achieved via oxidative and acid catalyzed cyclizations. The oxidative cyclization of siphonodictyal B occured spontaneously under aerobic oxidation conditions, which suggests that corallidictyals A and B are possibly artefacts of the isolation process. The mechanism of the oxidative cyclization of siphonodictyal B could be described as either an anionic 5-endo-trig cyclization (which is formally disfavoured by Baldwin's rules), or as an electrocyclic reaction, of an ortho-quinone intermediate.
通过氧化和酸催化环化反应，已实现了将西弗诺迪醇B高效转化为螺环天然产物珊瑚迪醇A - D。在有氧氧化条件下，西弗诺迪醇B会自发发生氧化环化反应，这表明珊瑚迪醇A和B可能是分离过程中的人工产物。西弗诺迪醇B氧化环化反应的机理可以描述为阴离子型5 - 内型 - 三取代环化反应（鲍德温规则对此反应形式上不利），或者是邻醌中间体的电环化反应。
