Divergent approach to the polymaxenolide and pinnaic acid cores

The divergent syntheses of the spirocyclic pyran core of polymaxenolide and the spirocyclic piperidine core of pinnaic acid have been achieved. Our divergent approach takes advantage of highly efficient Achmatowicz and aza-Achmatowicz rearrangements to generate the highly functionalised cores, which are then regioselectively modified.