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A Capping Step During Automated Glycan Assembly Enables Access to Complex Glycans in High Yield
Author(s) -
Yu Yang,
Koov Andrew,
Delbianco Martina,
Seeberger Peter H.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201801023
Subject(s) - glycan , chemistry , yield (engineering) , acetic anhydride , methanesulfonic acid , combinatorial chemistry , nucleophile , chromatography , organic chemistry , biochemistry , materials science , catalysis , glycoprotein , metallurgy
The products of multi‐step automated solid phase syntheses are purified after release from the resin. Capping of unreacted nucleophiles is commonplace in automated oligonucleotide synthesis to minimize accumulation of deletion sequences. To date, capping was not used routinely during automated glycan assembly (AGA) since previous capping protocols suffered from long reaction times and conditions incompatible with some protective groups. Here, a method using methanesulfonic acid and acetic anhydride for the fast and quantitative capping of hydroxyl groups that failed to be glycosylated is reported. Commonly used protective groups in AGA are stable under these capping conditions. The introduction of a capping step into the coupling cycle drastically improved overall yields by decreasing side‐products and simplifying purification, while reducing building block consumption. To illustrate the method, the biologically important tetrasaccharide Lc4, as well as a 50‐mer polymannoside were prepared.