An asymmetric total synthesis of the natural product erythro-8-O-4′-neolignan, machilin C, and its analog has been developed by Yamu Xia and Wei Wang, Qingdao University of Science and Technology, China.

The total synthesis of machilin C and its analog, erseal A, are possible using vanillin as a simple starting material in eight to twelve steps. A Sharpless dihydroxylation reaction elicits the asymmetric induction while a Mitsunobu reaction leads to inversion of the absolute configuration from the threo to the desired erythro isomer, according to the researchers. Neolignans are secondary metabolites found as racemic mixtures in the plant Machilus thunbergii of traditional Chinese medicine. However, it is the erythro isomer of these compounds that have potential as antimalarial drugs.

• Asymmetric synthesis of machilin C and its analogue
  Y. Xia, W. Wang,
  Chem. Pap. 2010, 64.
  DOI: 10.2478/s11696-010-0040-8