Total Synthesis of the Antitumor Antibiotic Basidalin

The first synthesis of the tetronamide antibiotic basidalin was accomplished in five steps and 39% overall yield from readily available 4-bromo-2-triiso­propyl­silyloxy­furan and 2-formyl-1,3-dithiane. Highlights include: (i) regio- and stereocontrolled assemblage of a pivotal (Z)-γ-ylidene-β-bromo­butenolide intermediate by stereodirected vinylogous aldol condensation (SVAC), (ii) installation of the amino group via aza-Michael addition/​elimination, and crucially (iii) facile access to basidalin by late-stage dithiane removal.