A synthetic method comprising the following steps: a) providing a disaccharide of formula 2 wherein Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, and X represents -OAc or -SR 5, with R 5 being selected from -Me, -Et, -Pr, -Bu, -Ph and -Tol; and a saccharide of formula 3 wherein R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, r is 1, 2 or 3; b) coupling of the disaccharide of formula 2 with the saccharide of formula 3 in presence of a catalyst to obtain a saccharide of formula 1 wherein Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, and r is 1, 2 or 3. a) providing a disaccharide of formula 2 wherein Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, and X represents -OAc or -SR 5, with R 5 being selected from -Me, -Et, -Pr, -Bu, -Ph and -Tol; and a saccharide of formula 3 wherein R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, r is 1, 2 or 3; Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, and X represents -OAc or -SR 5, with R 5 being selected from -Me, -Et, -Pr, -Bu, -Ph and -Tol; R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, r is 1, 2 or 3; b) coupling of the disaccharide of formula 2 with the saccharide of formula 3 in presence of a catalyst to obtain a saccharide of formula 1 wherein Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, and r is 1, 2 or 3. Nap represents 2-naphthylmethyl group, R 1 represents an orthogonal oxidation-stable and acid-stable protecting group, R 2 represents an orthogonal oxidation-stable and acid-stable protecting group, R 3 is an aryl or alkyl group, W represents -L-P or -Bn, P is -NR'R" or -N 3, R' and R" represent independently of each other -Bn, -Cbz, -Allyl or R' and R" form together phthaloyl, L represents -(CH 2) n - or -C 2 H 4 -O-C 2 H 4 -, n is an integer selected from 2, 3, 4, 5, 6, 7, 8, 9 and 10, and r is 1, 2 or 3.