“…All H atoms were found and the structure was refined by a blocked least-squares approach, with isotropic thermal parameters for the H atoms and anisotropic parameters for the others, to an R factor of 0.033. While it was expected that the absolute stereochemistry of chaetoglobosin A would be similar to that of the 11-cytochalasins to which it is chemically related and whose absolute configuration is known (Tsukuda & Koyama, 1972;Buchi, Kitaura, Yuan, Wright, Clardy, Demain, Glinsukin, Hunt & Wogan, 1973), there is no direct evidence and, therefore, both possible enantiomers were refined using anomalous-scattering factors for C, N and O. The expected enantiomer gave the lower R factor but the difference was not significant.…”