Synthesis of (+)-salvianolic acid A from sodium Danshensu

(+)-Salvianolic acid A, one of the most active components in the traditional Chinese medicine Danshen, has been synthesized over 10 steps in 6.5% overall yield. Starting from inexpensive ortho-vanillin and sodium Danshensu (synthesized via asymmetric catalysis in our group), the process consists of the following: A Wittig reaction that gives the desire product with absolute E-configuration, a demethylation reaction with AlCl3 in a satisfactory yield, and a practical deprotection of allylic groups to afford the terminal product (+)-salvianolic acid A. The current synthetic technology possesses the advantages of using inexpensive starting materials, mild reaction conditions and has the potential for use in large scale synthesis.