The invention provides methods and regents for the glycosylation of organic molecules. In one aspect, the invention provides a method for glycosylating a hydroxyl-containing organic compound (i.e., a glycosyl acceptor) comprising contacting a glycosyl donor with the hydroxyl-containing organic compound, in the presence of an oxidant, to yield a glycosylated organic compound. In certain embodiments, the methods provided herein provide glycosylation products with high anomeric selectivity. The methods can be applied to the synthesis of disaccharides, trisaccharides, polysaccharides, glycans, etc. Also provided herein are compounds (e.g., glycosyl donors and acceptors) which are useful building blocks in the provided reactions.