Enantioselective total synthesis of (+)-isoaltholactone

A facile enantioselective route to highly functionalized α,β-unsaturated -δ-lactones has allowed for the synthesis of (+)-isoaltholactone in 6.4% overall yield from furylmethanol. This approach derived its asymmetry by applying Sharpless kinetic resolution on racemic 2-furylmethanol. The resulting pyranone was produced in high enantioexcess and was stereoselectively transformed into (+)-isoaltholactone via a highly diastereoselective epoxidation and a key PPTS catalyzed intramolecular cyclization.