Unraveling the promoter effect and the roles of counterion exchange in glycosylation reaction.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37851803.
- Also identified by DOI 10.1126/sciadv.adk0531 and PMC identifier 10584349.
- Licence recorded as CC BY-NC.
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Abstract
The stereoselectivity of glycosidic bond formation continues to pose a noteworthy hurdle in synthesizing carbohydrates, primarily due to the simultaneous occurrence of S<sub>N</sub>1 and S<sub>N</sub>2 processes during the glycosylation reaction. Here, we applied an in-depth analysis of the glycosylation mechanism by using low-temperature nuclear magnetic resonance and statistical approaches. A pathway driven by counterion exchanges and reaction byproducts was first discovered to outline the stereocontributions of intermediates. Moreover, the relative reactivity values, acceptor nucleophilic constants, and Hammett substituent constants (σ values) provided a general index to indicate the mechanistic pathways. These results could allow building block tailoring and reaction condition optimization in carbohydrate synthesis to be greatly facilitated and simplified.