Chiral silylation reagents for the determination of absolute configurationby NMR spectroscopy

[GRAPHICS] We have investigated the use of chiral silylating reagents as analytical pr obes for determining the absolute stereochemistry of natural products by NM R spectroscopy. These reagents are prepared in high chemical yield in one s tep and can be used to derivatize chiral allylic alcohols which are incompa tible with ester-based methodologies, Microscale (similar to 400 nmol) deri vatization conditions have been defined. The resulting siloxane diastereome rs are readily distinguished by their H-1 NMR spectra.