A tandem deprotection-cyclization reaction of 1,1-diacylcyclopropanes is described which allows rapid access to structurally diverse 2,3-disubstituted chromones in good yields, and with straightforward purification. The utility of this reaction is showcased by the construction of the potent antibacterial marine natural product bromophycoic acid E scaffold.

The selective mono‐allylation of 1,3‐diketone containing compounds is described. The reaction proceeds under mild reaction conditions and in moderate to high yield (66–99 %). Using this procedure to access the key mono‐allylated intermediate, the hitherto difficult to access 3‐allyl chromones were synthesized in excellent yield (87–98 %). Finally, the utility of this newly developed procedure was showcased through the rapid synthesis of the scaffold of the xyloketal family of natural products.

A rapid and facile synthesis of benzannulated 6,5-spiroketals from vinyl 1,1-diacylcyclopropanes is reported. The method utilizes mild reaction conditions with good to excellent yields and high diastereoselectivity. This methodology was then used to construct the core of berkelic acid.

The problematic opportunistic pathogen Pseudomonas aeruginosa secretes a siderophore, pyoverdine. Pyoverdine scavenges iron needed by the bacteria for growth and for pathogenicity in a range of different infection models. PvdF, a hydroxyornithine transformylase enzyme, is essential for pyoverdine synthesis, catalysing synthesis of formylhydroxyornithine (fOHOrn) that forms part of the pyoverdine molecule and provides iron-chelating hydroxamate ligands. Using a mass spectrometry assay, we confirm that purified PvdF catalyses synthesis of fOHOrn from hydroxyornithine and formyltetrahydrofolate substrates. Site directed mutagenesis was carried out to investigate amino acid residues predicted to be required for enzymatic activity. Enzyme variants were assayed for activity in vitro and also in vivo, through measuring their ability to restore pyoverdine production to a pvdF mutant strain. Variants at two putative catalytic residues N168 and H170 greatly reduced enzymatic activity in vivo though did not abolish activity in vitro. Change of a third residue D229 abolished activity both in vivo and in vitro. A change predicted to block entry of N10-formyltetrahydrofolate (fTHF) to the active site also abolished activity both in vitro and in vivo. A co-purification assay showed that PvdF binds to an enzyme PvdA that catalyses synthesis of hydroxyornithine, with this interaction likely to increase the efficiency of fOHOrn synthesis. Our findings advance understanding of how P. aeruginosa synthesises pyoverdine, a key factor in host–pathogen interactions.

The first total synthesis of asterredione was efficiently accomplished over five linear steps and in 21.5% overall yield. As the crucial step, the 2-quaternary 1,3-cyclopentenedione skeleton of asterredione was readily achieved using the Darzens/ring-expansion strategy developed in our laboratory. The structure of synthesized asterredione was fully confirmed by X-ray crystallography.