The present invention relates to a method for preparing 2′-O-fucosyllactose and to the protected fucosyl donor of the formula (I) used in this method. The method comprises reacting the fucose derivative of the formula (I) below with the compound of the general formula (II), in the presence of an activating reagent. In the formulae (I) and (II), the variables are each defined as follows: X is Br or a S-bound radical, namely —SCN, —S(O)n—RX1or —S—RX2, wherein RX1 preferably is an optionally substituted phenyl, and RX2 preferably is C1-C4-alkyl, 2-oxazolin-2-yl, 2-thiazolin-2-yl, benzoxazol-2-yl, benzothiazol-2-yl or pyridin-2-yl; RSi are the same or different and are radicals of the formula SiRaRbRc, wherein Ra, Rb and Rc preferably are each methyl; R1 is a C(=O)—R11 radical or an SiR12R13R14 radical, wherein R11 is preferably methyl, phenyl or tert-butyl, and R12, R13 and R14 preferably are each methyl; R2 are the same or different and are C1-C8-alkyl or together form a linear C3-C6-alkanediyl, which is unsubstituted or has 1 to 6 methyl groups as substituents; R3 are the same or different and are C1-C8-alkyl or together form a linear C1-C4-alkanediyl, which is unsubstituted or has 1 to 6 methyl groups as substituents.