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Donor‐Reactivity‐Controlled Sialylation Reactions
Author(s) -
Asressu Kesatebrhan Haile,
Chang ChunWei,
Lam Sarah,
Wang ChengChung
Publication year - 2021
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.202100718
Subject(s) - chemistry , stereoselectivity , reactivity (psychology) , glycosyl , bromide , sialic acid , chemoselectivity , halide , trifluoromethanesulfonate , chlorine , glycosyl donor , catalysis , chloride , combinatorial chemistry , organic chemistry , medicine , biochemistry , alternative medicine , pathology
Although tremendous efforts have been made for the efficient preparation of sialosides, controlling the stereochemical outcome of sialylation reaction still remains one of the most challenging tasks due to the unique chemical structure of sialic acid. We developed a new strategy to statistically analyze the stereoselectivity of sialylation reactions on six types of p ‐tolyl thiosialosides in NIS/TfOH system using Relative Reactivity Value (RRV) as the indicator. Analysis of the reaction mechanism showed the formation of the relatively stable glycosyl bromide and glycosyl chloride intermediates from halide‐ and triflate‐containing promotors in the absence of an acceptor. We found that the α/β‐stereoselectivity, yields, and intermediate changes were associated with their donor reactivity. These findings enable to tailor the most suitable building blocks for stereo‐controlled sialylation reactions.