Palladium-catalyzed carbonylation. A new synthesis of .alpha.-methylene .gamma.-, .delta.-, .epsilon.-lactams and lactones including bicyclic lactams of pyrrolizidine and indolizidine skeletons
This Letter describes the asymmetric totalsynthesis of (+)-carneic acid A via the stereoselective IMDA reaction of (E,E,E)-triene, which was prepared from the commercially available methyl (S)-3-hydroxy-2-methylpropionate. By this asymmetric totalsynthesis, we verified that the reported absolute structure of naturally occurring carneic acid A must be revised.