An efficient enantioselective synthesis of argentilactone

Asymmetric allylboration of 2-octynal with (+)-B-allyldiisopinocampheylborane provides the corresponding homoallylic alcohol in 80% yield. The alkynenol is stereoselectively hydrogenated in the presence of Lindlar catalyst, converted to the corresponding acrylic ester, and cyclized by refluxing in dichloromethane in the presence of 10 mol% of Grubbs' catalyst to provide the natural enantiomer of (R)-(-)-argentilactone in 44% overall yield.