An approach toward constructing the trioxadispiroketal core in the DEF-ring of (+)-spirastrellolide A.

A concise and stereoselective synthesis of the trioxadispiroketal motif that embodies the DEF-ring of the marine macrolide (+)-spirastrellolide A is described. The synthetic approach features a sequence of cyclic acetal tethered ring-closing metathesis and Suárez oxidative cyclization, thereby constituting a viable strategy for constructing the Northern Half.