Asymmetric total synthesis of (+)-.DELTA.9(12)-capnellene

The first asymmetric total synthesis of the unnatural enantiomer of (-)-A9(12)-capnellene has been achieved in 14.1 % overall yield. The synthesis is based on the chiral nonracemic bicyclic lactam 15 derived from inexpensive (S)-valinol and levulinic acid. The goal of the synthesis, which was accomplished, was to reach the intermediate 13, originally reported in racemic form, and carry out the last step to the title compound.