Synthesis of (+)-limonidilactone and 12-epi-limonidilactone

The synthesis of (+)-limonidilactone from zamoranic acid is described. This synthesis has allowed the absolute configuration for the natural product (−)-limonidilactone be established. The synthesis of 12-epi-limonidilactone is also realized. In addition, a solid compound, which possesses a carbonyl group, has been isolated and identified as a hydrate stabilized by three hydrogen bonds.