Conformational studies on pertrimethylsilyl derivatives of some mono- and disaccharides by 220 MHz PMR spectroscopy

Abstract

The complete interpretation of 220 MHz PMR spectra and the accurate chemical shifts and coupling constants, obtained after computer simulation of the spectra, of a number of TMS-mono and -disaccharides are given. By means of an adapted Karplus equation the conformation of the derivatives has been studied in detail. All pyranose rings are found to occur in the Cl(D) chair conformation. As a consequence of their greater steric requirement, the OTMS groups deform the chair conformation more than the OAc groups. The preferred conformation of the C-5-CH{2}OTMS group is determined and found to be dependent on the configuration at C-4.