methyl 6-O-acetyl-2-O-benzyl-3,5-O-(di-tert-butylsilanediyl)-α-D-galactofuranosyl-(1→6)-2,3,4-tri-O-benzoyl-α-D-mannopyranoside | 1352442-78-4

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: methyl 6-O-acetyl-2-O-benzyl-3,5-O-(di-tert-butylsilanediyl)-α-D-galactofuranosyl-(1→6)-2,3,4-tri-O-benzoyl-α-D-mannopyranoside
• 英文别名: methyl 6-O-acetyl-2-O-benzyl-3,5-O-(di-tertbutylsilanediyl)-α-D-galactofuranosyl-(1->6)-2,3,4-tri-O-benzoyl-α-D-mannopyranoside
• CAS: 1352442-78-4
• 化学式: C₅₁H₆₀O₁₅Si
• 分子量: 941.114
• InChiKey: PALXUYQGWDXWLP-UCGIJBPCSA-N

反应信息

• 作为产物：
  描述：

  p-tolyl 2,6-di-O-benzoyl-3,5-O-(di-tert-butylsilanediyl)-1-thio-β-D-galactofuranoside 在 吡啶 、 sodium methylate 、 silver trifluoromethanesulfonate 、 sodium hydride 作用下， 以 甲醇 、 二氯甲烷 、 N,N-二甲基甲酰胺 为溶剂， 反应 8.88h， 生成 methyl 6-O-acetyl-2-O-benzyl-3,5-O-(di-tert-butylsilanediyl)-α-D-galactofuranosyl-(1→6)-2,3,4-tri-O-benzoyl-α-D-mannopyranoside
  参考文献：
  名称：

  Conformationally restricted 3,5-O-(di-tert-butylsilylene)-d-galactofuranosyl thioglycoside donor for 1,2-cis α-d-galactofuranosylation

  摘要：

  A conformationally restricted 2-O-benzyl-3,5-O-di-tert-butylsilylene-beta-D-thiogalactofuranoside donor was prepared from benzyl alpha-D-galactofuranoside and its donor capability was studied for stereoselective 1,2-cis alpha-D-galactofuranosylation. An unusual chemical behavior in benzylation and hydrogenolysis reactions was observed after the introduction of the 3,5-O-di-tert-butylsilylene protecting group into the galactofuranosyl moiety. The influence of the solvent, temperature, and activating system was evaluated. The NIS/AgOTf system, widely used in 1,2-cis beta-arabinofuranosylation, was not satisfactory enough for 1,2-cis galactofuranosylation. However, moderate to high alpha-selectivity was obtained with all the acceptors employed when using p-NO2PhSCl/AgOTf as a promoting system, in CH2Cl2 at - 78 degrees C. The order of the addition of the reactants (premixing or preactivation) did not affect substantially the stereochemical course of the glycosylation reaction. The alpha-D-Galf-(1 -> 6)-D-Man linkage was achieved with complete diastereoselectivity by preactivation of the conformationally constrained thioglycoside donor. (C) 2014 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.carres.2014.07.024

文献信息

• Glycosylation studies on conformationally restricted 3,5-O-(di-tert-butylsilylene)-d-galactofuranosyl trichloroacetimidate donors for 1,2-cis α-d-galactofuranosylation
  作者：Mariano J. Tilve、Carola Gallo-Rodriguez

  DOI：10.1016/j.carres.2011.10.004

  日期：2011.10

  Conformationally restricted 3,5-O-di-tert-butylsilylene-D-galactofuranosyl trichloroacetimidate donors were synthesized from allyl alpha-D-galactofuranoside for the construction of 1,2-cis alpha-D-galactofuranosyl linkages. Glycosylation reactions were performed with several acceptors, including D-galactono-1,4-lactone, D-rhamnopyranosyl, and D-mannopyranosyl derivatives. The influence of the temperature and the reaction solvents was evaluated, as well as the 6-O-substitution pattern of the donor. The higher alpha-selectivities were obtained at -78 degrees C in diethyl ether as solvent. 6-O-Acetyl substitution on constrained donor increased the alpha-selectivity compared to the 6-O-benzyl substitution. Almost no selectivities were observed in the non-participating solvent CH2Cl2. In contrast, ethereal solvents enhanced the alpha-selectivity suggesting a participating effect in the reaction intermediate. (C) 2011 Elsevier Ltd. All rights reserved.