Current tools for chemical glycosylation: Where are we now?

Glycosylation procedure has long been categorized to one of the most delicate synthetic techniques in the field of organic chemistry, since it requires extremely dry and mild conditions, to prevent the decomposition of substrates, intermediates, and products as well as to activate only appropriate donor species. Although chemists have made great efforts to overcome the difficulty by brushing up their skills to carry out moisture-sensitive reactions and by developing numbers of acid-promoted glycosylation chemistry, there are still troublesome cases that cannot be addressed by human hands. To circumvent this dead-end situation, chemists turned their attention from training their own skills to the development of machinery which can conduct operations that human cannot. In this review, we introduced tools, currently applied and/or developed to facilitate chemical glycosylation reactions. We focused on brand-new results using electrochemical and microfluidic machinery, as well as a simple but useful apparatus, which have never been reviewed yet.