Synthetic Organic Chemistry
Total synthesis of phacelocarpus-2-pyrone A
Isolated from the Australian marine alga Phacelocarpus Labillardieri in 1986, this natural product belongs to a small family of unique pyrone-containing natural products. Some members of this family have displayed an intriguing biological profile, including potent inhibition of bee-venom derived phospholipase A2 and neuromuscular blocking activity. It consists of a 19-membered macrocyclic ring containing a number of interesting structural features, including an embedded 2-pyrone unit connected to a unique vinyl ether. This itself forms part of a ‘skipped unsaturated’ system where four carbon-carbon multiple bonds are each separated by one methylene unit. In 2015, the synthesis of this target and it's arene mimetic was completed within our laboroatory. We revised the proposed stereochemistry around the vinyl ether connecting the 2-pyrone motif, as part of this work. The project is part of a long-standing collaboration with Prof. R. J. K. Taylor.
The latter stages of the total synthesis are shown below:
The yields of the Wittig and Stille reactions (last two steps) are optimised, which included the development of a new Pd catalyst for cross-coupling reactions, AsCat. We continue to work on the synthesis of 2-pyrone derivatives.