An efficient enantioselective synthesis of argentilactone

Asymmetric allylboration of 2-octynal with (+)-B-allyldiisopinocampheylbora ne provides the corresponding homoallylic alcohol in 80% yield. The alkynen ol is stereoselectively hydrogenated in the presence of Lindlar catalyst, c onverted to the corresponding acrylic ester, and cyclized by refluxing in d ichloromethane in the presence of 10 mol% of Grubbs' catalyst to provide th e natural enantiomer of (R)-(-)-argentilactone in 44% overall yield.