A one-step C-linked disaccharide synthesis from carbohydrate allylsilanes and tri-O-acetyl-D-glucal.
The reaction of protected glucuronic esters 2 and 7, as well as D-glucuronolactone derivative 11, with (trimethylsilyl)methylmagnesium chloride in ether led to the corresponding stable bis-silyl adducts 3, 8, and 12, respectively. In Peterson-type reactions catalysed with mild acid, these compounds yielded carbohydrate allylsilanes 4, 9, and 13, respectively. Synthons 4 and 9 were coupled with tri-O-acetyl-D-glucal in a boron trifluoride-catalysed "carbon-Ferrier rearrangement" reaction to give C-linked disaccharides i.e., so-called "C-disaccharides" 16 and 17, respectively, in fair yields. Structural assignments of the anomeric configuration at the C-glycosylic carbon in the 2,3-unsaturated ring of these coupling products with the aid of n.m.r. spectroscopic methods unambiguously showed that alpha-D-C-linked disaccharides had been formed.
de Raadt
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Institut für Organische Chemie der Technischen Universität Graz, Austria.
Stütz
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D002125:Calcium Gluconate / Q000031:analogs & derivatives; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis*; D005965:Glucuronates / Q000737:chemistry*; D020723:Glucuronic Acid; D008969:Molecular Sequence Data; D012821:Silanes / Q000737:chemistry
D004187:Disaccharides; D005965:Glucuronates; D012821:Silanes; C004940:glucuronolactone; D020723:Glucuronic Acid; D002125:Calcium Gluconate