Chemical Synthesis of a Bisphosphorylated Mannose‐6‐Phosphate N‐Glycan and its Facile Monoconjugation with Human Carbonic Anhydrase II for in vivo Fluorescence Imaging

Efficient chemoenzymatic synthesis of an N-glycan isomer library

“…Installation of β-mannoside, the most challenging task in N-glycan synthesis, was accomplished using Crich-Kahne conditions with satisfying yield and β-selectivity. 17 The benzylidene acetal ring can be selectively opened at either C6-OH 9 or C4-OH 18 of the β-mannoside for further chemical assembly. In order to prepare target N-glycans, 8 GlcNAc terminated core structures (Fig.…”

Chemoenzymatic synthesis of ADP-d-glycero-β-d-manno-heptose and study of the substrate specificity of HldE

“…Phosphorylation of compound 18 in presence of dibenzyl N , N -diisopropyl phosphoramidite and 1H -tetrazole, followed by in situ m -CPBA oxidation gave the compound 19 . 22 The final deprotection of benzyl groups was achieved using Pearlman’s catalyst (Pd(OH) 2 /C) under H 2 to afford the desired D,D-heptose-7-phosphate 2 in 92% yield.…”

Chemoenzymatic Synthesis and Receptor Binding of Mannose-6-Phosphate (M6P)-Containing Glycoprotein Ligands Reveal Unusual Structural Requirements for M6P Receptor Recognition

“…12,15 Thus, we decided to use a similar synthetic strategy to introduce the phosphate group at a late stage. The synthesis commenced with the glycosylation between the glycosyl donor ( 1 ) 12 and the disaccharide acceptor ( 2 ), 37 under the promotion of N -iodosuccinimide (NIS)/TfOH to provide the tetrasaccharide ( 3 ), in which the C6-OH group of the terminal mannose moiety was selectively protected with a TIPS group (Scheme 1). Regioselective benzylidene ring opening was achieved by treatment of 3 with Et 3 SiH/PhBCl 2 to provide tetrasaccharide derivative ( 4 ) with a free OH at the C6 of the core β -mannose moiety.…”

“…A detailed structure–activity relationship study has been hampered by the difficulties in obtaining structurally well defined phosphorylated oligosaccharides and homogeneous M6P-containing glycoproteins relevant to the natural M6P ligands. 12,14–17 As an effort to address the problem, we have launched a project aiming to synthesize homogeneous phosphoglycopeptides and phosphoglycoproteins carrying natural M6P-containing glycans and to use them as probes to decipher the ligand structural requirements for M6P receptor recognition. For this purpose, we sought to explore the chemoenzymatic method that we and other groups have previously developed, which takes advantage of the transglycosylation activity of a class of endo- β - N -acetylglucosaminidases (ENGases) and related glycosynthase mutants to ligate a preassembled oligosaccharide (in the form of oligosaccharide oxazoline) to a GlcNAc-peptide or -protein to form a homogeneous glycopeptide or glycoprotein.…”