A method for asymmetric synthesis of (-)- Anisomelic Acid

A method for asymmetric synthesis of (−)-Anisomelic Acid, characterized by comprising:

• 1) preparing an aldehydes and ketone compound 1 by using a chiral compound (−)-Costunolide as starting material under the condition of ozonative decomposition;
• 2) preparing an unsaturated lactone compound (Z)-3 and an unsaturated lactone compound (E)-3 by using the aldehydes and ketone compound 1 and a phosphate compound 6 under alkaline condition;
• 3) preparing a tetraene compound 4 by using the unsaturated lactone compound (Z)-3 under 1,2-addition condition promoted by cerium trichloride and the subsequent elimination;
• 4) preparing a 14-membered macrocyclic compound (Z)-5 and a 14-membered macrocyclic compound (E)-5 by using the tetraene compound 4 under the condition of olefin metathesis;
• and
• 5) preparing a natural product (−)-Anisomelic Acid by using the 14-membered macrocyclic compound (E)-5 under the conditions of silica removal and hydrolysis;
• wherein the chemical formulae of each compound are shown below:
• and
• wherein the R group in the compound 6, the compound (Z)-3, the compound (E)-3, the compound 4, the compound (E)-5 and the compound (Z)-5 is alkoxy group, aromatic oxygen group, alkylamine group, aromatic amine group, alkyl sulfhydryl group, aromatic sulfhydryl group, or silicon group.