Abstract:
The synthesis of the ABC spiroacetal-containing fragment of the marine biotoxins, the pectenotoxins (PTXs), is described. The synthetic strategy involves appendage of the highly substituted tetrahydofuran C ring to the AB spiroacetal unit via stereocontrolled cyclization of a γ-hydroxyepoxide. The bis-spiroacetal moiety of the spirolide family of shellfish toxins is also described, making use of an iterative radical oxidative cyclization strategy.