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) |
|---|---|
| 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 |
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Keywords
- β-D-Glycosyl iodides
- Glycosyl iodides
- NMR characterization
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Organic Chemistry
Cite this
Mechanistic studies on the stereoselective formation of glycosyl iodides : First characterization of β-D-glycosyliodides. / Gervay-Hague, Jacquelyn; Nguyen, Truc N.; Hadd, Michael J.
In: Carbohydrate Research, Vol. 300, No. 2, 12.05.1997, p. 119-125.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Mechanistic studies on the stereoselective formation of glycosyl iodides
T2 - First characterization of β-D-glycosyliodides
AU - Gervay-Hague, Jacquelyn
AU - Nguyen, Truc N.
AU - Hadd, Michael J.
PY - 1997/5/12
Y1 - 1997/5/12
N2 - 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.
AB - 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.
KW - β-D-Glycosyl iodides
KW - Glycosyl iodides
KW - NMR characterization
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UR - http://www.scopus.com/inward/citedby.url?scp=0030914044&partnerID=8YFLogxK
U2 - 10.1016/S0008-6215(96)00321-7
DO - 10.1016/S0008-6215(96)00321-7
M3 - Article
VL - 300
SP - 119
EP - 125
JO - Carbohydrate Research
JF - Carbohydrate Research
SN - 0008-6215
IS - 2
ER -