Glycosidation of Methanol with Ribose: An Interdisciplinary Undergraduate Laboratory Experiment

Abstract

This exercise provides students hands-on experience with the topics of glycosidation, hemiacetal and acetal formation, proton nuclear magnetic resonance (1H NMR) spectroscopy, and kinetic and thermodynamic product formation. In this laboratory experiment, the methyl acetal of ribose is synthesized, and the kinetic and thermodynamic products of the reaction are identified using a 300 MHz NMR spectrometer with a variable temperature probe. The results of this reaction under two different sets of conditions reveal that alpha forms of ribosides are less stable than beta forms and that the kinetic products are furanosides, whereas the thermodynamic products are pyranosides. It can be performed as a single 3-h laboratory session or as a series of several sessions if students collect their own NMR spectra and use longer reaction times.