This account highlights an iron-catalyzed exclusively 1,2--selective glycosylation method for aminoglycoside synthesis. This selective nitrogen atom transfer reaction is effective for a broad range of glycosyl donors and acceptors, and it can be operated in a reiterative fashion and scaled up to the multi-gram scale. Mechanistic studies revealed a unique yet generally applicable glycosylation mechanism in which the iron catalyst activates a glycosyl acceptor and an oxidant when it facilitates the cooperative atom transfer of both moieties to a glycosyl donor in an exclusively -selective manner.