Total Synthesis of (-)-Exiguolide

The first total synthesis of the naturally occurring enantiomer of exiguolide ((-)-1) has been completed. This very convergent synthesis features the following as main steps: (i) a Trost's ruthenium-catalyzed ene-yne cross-coupling reaction (this complex transformation allows the challenging control of the C5-C28 double bond geometry along with the stereoselective construction of the tetrahydropyran ring A) and (ii) a very efficient one-pot, two-step stereoselective conjugated allylic alcohol substitution that allowed the control of the C15 stereogenic center.