Phantolide analogues 1a–1d were newly synthesized to evaluate their odor profiles. The enantiomers of 1a and 1b were also synthesized. Both (S) enantiomers of 1a and 1b had musk odor although weakly, and but neither of the (R) enantiomers 1a and 1b had musk odor. During the investigations, we encountered the undesirable racemization in Friedel-Crafts reaction of the intermediate (S)-5.