The ability to selectively synthesize a specific anomer is important, especially within medicinal chemistry, as the two anomers of a glycoside can have different biological activity. Many elegant methods for selectively obtaining both β-glycosides and α-glycosides have been established, but each with a limited range of substrate compatibilities. New tools are still needed in the glycosylation toolbox, as obtaining a specific anomer is still a major challenge for some carbohydrates due to the multiple factors that influence the stereochemical outcome of glycosylations (Figure ; left). Many of the determining factors are related to the Figure Left: illustration of a generic glycosylation and factors that can influence its stereochemical outcome. Right: overview over this work and previous work which apply machine learning to chemical glycosylations. a For prediction of the anomeric ratio with a random split of the dataset into test and training data. glycosyl donor's properties, especially the C-2 substituent. Expert explanations of stereoselectivity often attribute outcomes to steric and electronic properties of the C-2 substituent , neighboring group participation (NGP) , and the Δ2 effect . Other important factors related to the glycosyl donor are its conformation and electrophilicity (e.g. armed vs disarmed ). The size and the electronic properties of the acceptor have also been shown to play a crucial role in the stereochemical outcome. Furthermore, the electronic and steric properties of the product can also influence the stereochemistry of the product, for instance via the anomeric effect. In addition to substrate-dependent effects, solvents are also known to affect the outcome of glycosylations through polarity-related effects and direct solvent effects where the solvent reacts with the reactants to form reactive intermediates. Temperature can also have a great influence on the stereochemistry of the glycoside product , and most glycosylations also require the addition of an activator (promotor or catalyst), which can influence the stereochemical outcome by formation of intermediates either through ionic or covalent interactions. Overall, it should be evident that the stereochemical outcome of glycosylation reactions is governed by multiple competing factors and effects, complicating our ability to predict anomeric selectivity.