Synthesis of Natural Rubrolides B, I, K, L, M, O and Analogues

The chlorinated natural products, rubrolides B, I, K, L, M and O and analogues were synthesized in only five steps employing a robust and divergent synthetic strategy. The synthesis is performed without using protecting groups starting from a key intermediate, which can be synthesized from commercially available tetronic acid in only two steps. Selective halogenation and vinylogous aldol condensation enable the efficient synthesis of highly halogenated natural occurring rubrolides as well as synthetic analogues to build up a compound library for antiviral and antibiofilm testing. All synthesized compounds were then tested for their activity against the two influenza A virus strains pH1N1 and H3N2 as well as for their antibiofilm activity. Naturally occurring as well as synthetic analogues showed promising antiviral and antibiofilm activities.