Adrian W. Markwell-Heys and Jonathan H. George
Org. Biomol. Chem., 2016,14, 5546-5549
DOI:
10.1039/C6OB00171H,
Communication
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.