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.