The fungal metabolite TAN‐2483B has a 2,6‐trans‐relationship across the pyran ring of its furo[3,4‐b]pyran‐5‐one core, which has thwarted previous attempts at its synthesis. We have now developed a chiral pool approach to this core and prepared side‐chain analogues of TAN‐2483B. The synthesis relies on ring expansion of a reactive furan ring‐fused dibromocyclopropane and alkynylation of the resulting pyran. The furan ring is constructed by palladium‐catalysed carbonylative lactonisation. Various side‐chains are appended through Wittig‐type chemistry. The prepared analogues showed micromolar activity towards cancer cell lines HL‐60, 1A9 and MCF‐7 and certain human disease‐relevant kinases, including Bruton's tyrosine kinase (Btk).

The intramolecular addition of tosylureas to allenes is highly syn-/anti-diastereoselective when employing a palladium or rhodium-based catalytic system and affords 1,3-cyclic ureas. Under palladium catalysis a range of thermodynamic anti-tetrahydro­pyrimidinones are accessible, while rhodium catalysis allows synthesis of the kinetic syn-tetrahydro­pyrimidinones. For a representative scope of substrates both cyclic ureas were obtained in excellent yields and diastereoselectivities. The obtained tetrahydro­pyrimidinones were shown to be easily deprotected and modified to demonstrate the synthetic value.

Side‐chain analogues of the natural product TAN‐2483B have been synthesised and tested for cancer cell and kinase inhibition. The furo[3,4‐b]pyran scaffold was constructed through ring expansion of a mannose‐derived cyclopropane, alkynylation and carbonylative lactonisation. Various side chains were appended using Wittig methodology. The cover picture illustrates key intermediates in the synthesis leading to the prepared analogues. These are overlaid on a New Zealand native fern, signifying the origin of the research presented in this special issue on Chemistry in New Zealand. More information can be found in the Full Paper by Joanne Harvey et al. on page 1230 in Issue 8, 2019 (DOI: 10.1002/asia.201801767).