Philip DeShong investigated total synthesis of tirandamycin A. In the reported sequence, related pyranones were converted into a fused lactone; the discussion used a proposed mechanism to qualify the relative stereochemistry, rather than claiming that the reported NMR spectroscopy alone fixed the assignment unambiguously.[ref]
Total synthesis of (±)-tirandamycin A by Philip DeShong and others. 1985, pp.5220–5221, Schemes II–III and stereochemical-assignment discussion
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