Abstract
Treatment of glycosyl acetates with one equivalent of iodotrimethylsilane at low temperature results in the quantitative formation of glycosyl iodides. Carbohydrates that possess a participating group at the C-2 position initially form β-D-glycosyl iodides, which quickly equilibrate to the α-iodo anomers. The β anomer of peracetylated glucose reacts faster than the α anomer, presumably because the C-2 acetate can assist in displacing the silylated anomeric acetate. In contrast, the α anomer reacts faster than the β anomer in substrates lacking a participating group at C-2. For example, activation of 1-O-acetyl-2,3,4,6-tetra-O-benzyl-α-D-glucopyranose leads to formation of the β iodide, while the corresponding β acetate produces the α iodide. Although the β iodides quickly equilibrate to the α anomers, they can be prepared in sizable quantities at low temperatures where equilibration is slow. This report describes the first stereoselective formation and characterization of β-D-glycosyl iodides.
Original language | English (US) |
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Pages (from-to) | 119-125 |
Number of pages | 7 |
Journal | Carbohydrate Research |
Volume | 300 |
Issue number | 2 |
DOIs | |
State | Published - May 12 1997 |
Externally published | Yes |
Keywords
- β-D-Glycosyl iodides
- Glycosyl iodides
- NMR characterization
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Organic Chemistry