The total synthesis of a series of new carolacton derivatives that mainly lack selected
methyl substituents along the polyketide backbone is reported. Their inhibitory activity
towards bacterial biofilms revealed that selective removal of the methyl group at
C10 does not have a major effect on biological activity, whereas additional removal
of the methyl group at C14 in carolacton results in a large decrease in antibacterial
activity. A key new feature of this work is the replacement of the Nozaki–Hiyama–Kishi
(NHK) vinylation with a titanium-mediated protocol for the fusion of the two main
fragments.
Key words
antibiotics - biofilms - carolacton - Nozaki–Hiyama–Kishi reaction - polyketides -
structure–activity relationship studies - total synthesis