Total Synthesis Establishing the Correct Structures of Robustadials A and B. Reinterpretation of NMR Data

Article abstract of DOI:10.1021/jo00268a016

A total synthesis from (+)-nopinone establishes as 10f and 11f respectively the structures, including absolute stereochemistry, for robustadials A, and B, natural products isolated from the antimalarial Chinese herbal medicinal extract of Eucalyptus robusta leaves.The 1H and 13C NMR spectral assignments for robustadial B dimethyl ether (11e) are examined in detail.It is then shown that the Overhauser enhancement data interpreted originally to support 1b as the structure for this ether actually consistent with both structures 1b and 11e.