Using specialised NMR methods, you can discover what the reactive intermediates are in reactions of sugar molecules, says a paper in JACS.

If you work with sugar molecules, you almost automatically run into the problem of ‘stereoselective glycosylation reactions’: how do you get one sugar molecule to another sugar molecule in the intended way? ‘That glycosylation reaction mechanism can be very simple’, says Thomas Boltje, associate professor of chemical biology at Radboud University (RU). ‘The reactive intermediate is in some cases easy to detect with, for example, NMR, and explains the formation of the reaction product. But in many cases you see a reaction intermediate that cannot possibly lead directly to the product you made. In these cases, the structure of the “real” reactive intermediate is unknown.’