5041-92-9Relevant articles and documents
Revisit of the phenol O-glycosylation with glycosyl imidates, BF 3·OEt2 is a better catalyst than TMSOTf
Li, Yali,Mo, Huaping,Lian, Gaoyan,Yu, Biao
, p. 14 - 22 (2013/01/15)
With BF3·OEt2 as the catalyst, the glycosylation of phenols with glycosyl trichloroacetimidates (or N-phenyl trifluoroacetimidates) bearing 2-O-participating groups leads to the desired 1,2-trans-O-glycosides in generally excellent yields without formation of the 1,2-cis-anomers. However, with TMSOTf as the catalyst, the outcomes of the corresponding phenol O-glycosylation are highly dependent on the nucleophilicity of the phenols; less nucleophilic is the phenol, higher amounts of the 1,2-cis-O-glycoside together with more side-products are generated. 1,2-Orthoesters have been found to be the major products at a low temperature (a higher temperature. BF 3·OEt2 is an effective catalyst to promote the conversion of 1,2-orthoesters into the corresponding 1,2-trans-O-glycosides. However, the 1,2-orthoesters could be converted into the dioxolenium triflate and glycosyl triflate in the presence of TMSOTf, these intermediates which might be in equilibrium with the glycosyl oxocarbenium related species lead to the final mixture of the α/β-O-glycosides and side-products.
Stereoselectivity of reactions at the glycoside center of carbohydrates: VII. Synthesis of aryl α- and -β-D-glucopyranosides by Helferich, catalyzed by boron trifluoride etherate
Sokolov,Zakharov,Studentsov
, p. 806 - 811 (2007/10/03)
13C NMR spectroscopy was used to study the stereoselectivity of glycosylation of phenols with the α and β anomers of penta-O-acetyl-D-glucopyranose, penta-O-trifluoroacetyl-D-glucopyranose, and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-D-glucopyranose in the presence of boron trifluoride etherate at varied temperature, time, and catalyst amount. The boron trifluoride etherate-catalyzed reaction of penta-O-acetyl-β -D-glucopyranose and 2,3,4,6-tetra-O-acetyl-1-O-trifluoroacetyl-β -D-glucopyranose with phenols occurs with a high stereocontrol to give, depending on conditions, predominantly 1,2-cis- or 1,2-trans-aryl-glycosides. This reaction can be used for preparative synthesis of the α- and β-anomeric forms of glycosides of a wide range of phenols.
Solid-liquid phase transfer catalyzed novel glycosylation reaction of phenols
Hongu, Mitsuya,Saito, Kunio,Tsujihara, Kenji
, p. 2775 - 2781 (2007/10/03)
A facile and mild glycosylation reaction in solid-liquid two-phase system (powdered K2CO3/CHCl3) containing phase transfer catalyst was found to be efficient for preparation of glucosides of 2', 6'-dihydroxyacetophenone (1) and other various substituted phenols.