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).
Keywords: TAN-2483B analog; alpha-selective alkynylation; cyclopropane ring expansion; fungal metabolites; furo[3,4-b]pyran-5-one; palladium-catalyzed carbonylation.
© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.