Total Synthesis and Bioactivity Studies of Fungal Metabolite (−)-TAN-2483B

The first total synthesis of (−)-TAN-2483B, a fungal metabolite possessing a densely functionalized furo­[3,4-b]­pyran-5-one framework, is achieved in 14 steps from d-mannose. Generation of the 2,6-trans-pyran is by cyclopropane ring expansion followed by α-selective alkynylation. Julia–Kocienski olefination introduces the E-propenyl side chain. Alkyne functionalization and carbonylation stereoselectively establish the bicyclic core of (−)-TAN-2483B. Inhibition of kinases Btk and Bmx, bacterial priority pathogens, and cytokine production in splenocytes indicates promising therapeutic potential.