Asymmetric Total Synthesis of Rugulactone, an α-Pyrone from Cryptocarya rugulosa

A total asymmetric synthesis of rugulactone, a naturally occuring alpha-pyrone isolated from Cryptocarya rugulosa, is reported. The synthesis involved a cross-metathesis coupling reaction to construct the internal E-olefin group, a Still-Gennari olefination to construct the Z-configured alpha,beta-unsaturated ester group, and a one-pot deprotection and intramolecular lactonization reaction. The stereochemistry at C5 was controlled by the use of a chiral pool.