Confirmation of the absolute configuration of Stachybotrin C using single-crystal X-ray diffraction analysis of its 4-bromobenzyl ether derivative.

The absolute configuration of Stachybotrin C was confirmed in this study. After synthesizing the dimethyl ethers of Stachybotrin C, the C-8 epimer was analyzed by 1D NOESY. However, the stereochemistry determination was difficult through the NOE correlations. Instead, the di(4-bromobenzyl) ether of Stachybotrin C was derived and used for X-ray diffraction analysis, because its single crystal was easier to obtain than that of the original Stachybotrin C. The stereochemistry of Stachybotrin C was determined to be (8S, 9R). This derivatization approach may also be used to prepare single crystals of the analogues.