Asymmetric total synthesis of four bioactive lignans using donor-acceptor cyclopropanes and bioassay of (-)- and (+)-niranthin against hepatitis B and influenza viruses.

The asymmetric total synthesis of four lignans, dimethylmatairesinol, matairesinol, (-)-niranthin, and (+)-niranthin has been achieved using reductive ring-opening of cyclopropanes. Moreover, we performed bioassays of the synthesized (+)- and (-)-niranthins using hepatitis B and influenza viruses, which revealed the relationship between the enantiomeric structure and the anti-viral activity of niranthin.