Methods for modular synthesis of n-glycans and arrays thereof

A D1 and D2/D3 arm module having the general formula (II)

• wherein, each of R1, R2, R3, and R4 is —H or a permanent protecting group that is stable under conditions used to remove the orthogonal protecting groups and is preferably benzyl (Bn) or acetyl (Ac) or benzoyl (Bz), or independently selected from
• wherein, Each of R5, R6, R7, and R8 is —H or independently a permanent protecting group that is stable under conditions used to remove the orthogonal protecting groups and is preferably benzyl (Bn) or acetyl (Ac) or benzoyl (Bz);
• each of R9 and R10 is —H or independently a permanent protecting group that is stable under conditions used to remove the orthogonal protecting groups and is preferably benzyl (Bn) or acetyl (Ac) or benzoyl (Bz), or a protected fucoside residue connected via α1,3 linkage to GlcNAc and/or α1,2 linkage to galactose;
• R11 is —H, Me (methyl) or Et (ethyl);
• R12 is —H or independently a permanent protecting group that is stable under conditions used to remove the orthogonal protecting groups and is preferably benzyl (Bn) or acetyl (Ac) or benzoyl (Bz), or protected Neu5Ac residue connected via α2,6 linkage;
• R13 is —H or independently a permanent protecting group that is stable under conditions used to remove the orthogonal protecting groups and is preferably benzyl (Bn) or acetyl (Ac) or benzoyl (Bz), or independently selected from
• X is —OR14 or —SR15 or leaving group;
• wherein, R14 is H, alkyl, alkenyl, alkynyl, aryl or substituted aryl;
• a protecting group such as a silyl or substituted silyl, preferably thexyldimethylsilyl (TDS), t-butyldimethylsilyl (TBS), t-butyldiphenyl silyl (TBDPS), triisopropylsilyl (TIPS), trimethylsilyl (TMS), or triethylsilyl (TES);
• methyl (Me), acetyl (Ac), benzyl (Bn), 2-naphthylmethyl (nap) or 1-naphthylmethyl (1-Nap);
• para-methoxy benzyl ether (PMB), methoxy phenyl ether (PMP), allyl ether (allyl), or an anomeric leaving group such as trichloroacetimidate —C(NH)—CCl3, phenyltrifluoroacetimidate —C(NPh)-CF3, trifluoroacetimidate —C(NH)—CF3;
• thioalkyl, thiophenyl, and more preferably fluoride;
• R15 is H, alkyl, aryl, or substituted aryl, preferably methyl, ethyl, phenyl, tosyl, or tolyl;
• Y is —NHR16;
• and R16 is preferably selected from the group consisting of 9-fluorenylmethoxycarbonyl (Fmoc), allyloxycarbonyl (Alloc), [2,2,2-Trichloroethoxycarbonyl] (Troc), acetyl (Ac), phthalimido (Phth), carbobenzyloxy (Cbz) and tert-butoxycarbonyl (Boc);
• wherein “D1 and D2/D3 arm modules” refers to N-glycans.

A method for synthesizing diverse glycans suitable for generating glycan arrays wherein the method comprises:

• a) generating orthogonally protected core trisaccharide of claim 1 and D1 and D2/D3 arm modules of claim 2,
• b) performing Stereo- and regio-selective glycosylation of D1 and D2/D3 arm modules of claim 2 to 3-O or/and 6-O positions of orthogonally protected core trisaccharide of claim 1,
• c) Unmasking or removal of protecting groups to obtain the high mannose, hybrid and bi-, tri- and tetraantennary complex-type glycans, and
• d) performing enzymatic sialylation to generate a library of sialylated glycans.

An array of N-glycans immobilized on a substrate wherein the array is fabricated by a method comprising:

• (a) providing a substrate;
• (b) attaching the N-glycan via a linker to the substrate;
• and
• (c) immobilizing a plurality of N-glycan moieties at discrete locations on the surface of the substrate.