Protecting‐Group‐Free Total Syntheses of Rubrolide R and S

This is the authors' abstract. We don't add key points for this paper.

The two marine natural products rubrolide R (1) and S (2) were synthesised in only three linear steps starting from commercially available tetronic acid without using protecting‐group chemistry. Key steps in the syntheses were the Pd‐catalysed Suzuki–Miyaura cross‐coupling followed by a vinylogous aldol condensation. Both compounds have been tested for their antibiotic and antiviral activities. At a concentration of 10 µm rubrolide R (1) and S (2), a 2‐log and 1.5‐log reduction in virus titre has been detected for a seasonal influenza virus (H3N2) and the pandemic swine influenza virus (pH1N1), respectively.