methyl 4-O-(2,3-di-O-benzyl-4,6-O-[α-2-(2-iodophenyl)ethylthiocarbonyl]ethylidene-β-D-mannopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside | 887699-67-4

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: methyl 4-O-(2,3-di-O-benzyl-4,6-O-[α-2-(2-iodophenyl)ethylthiocarbonyl]ethylidene-β-D-mannopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside
• 英文别名: S-[2-(2-iodophenyl)ethyl] (2S,4aR,6S,7S,8S,8aR)-6-[[(3aR,4R,6S,7S,7aR)-4-methoxy-2,2,6-trimethyl-4,6,7,7a-tetrahydro-3aH-[1,3]dioxolo[4,5-c]pyran-7-yl]oxy]-2-methyl-7,8-bis(phenylmethoxy)-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxine-2-carbothioate
• CAS: 887699-67-4
• 化学式: C₄₁H₄₉IO₁₁S
• 分子量: 876.804
• InChiKey: VYLFMQCZBVIVSB-PSMWFRDJSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6.2
• 重原子数：
  54
• 可旋转键数：
  14
• 环数：
  7.0
• sp3杂化的碳原子比例：
  0.54
• 拓扑面积：
  135
• 氢给体数：
  0
• 氢受体数：
  12

反应信息

• 作为反应物：
  描述：

  methyl 4-O-(2,3-di-O-benzyl-4,6-O-[α-2-(2-iodophenyl)ethylthiocarbonyl]ethylidene-β-D-mannopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside 在 偶氮二异丁腈 、 三正丁基氢锡 、 sodium methylate 作用下， 以 甲苯 、 甲醇 为溶剂， 反应 5.0h， 以74%的产率得到methyl 4-O-(2,3-di-O-benzyl-β-D-rhamnopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside
  参考文献：
  名称：

  4,6-O-[1-Cyano-2-(2-iodophenyl)ethylidene] Acetals. Improved Second-Generation Acetals for the Stereoselective Formation of β-d-Mannopyranosides and Regioselective Reductive Radical Fragmentation to β-d-Rhamnopyranosides. Scope and Limitations

  摘要：

  The [1-cyano-2-(2-iodophenyl)]ethylidene group is introduced as an acetal-protecting group for carbohydrate thioglycoside donors. The group is easily introduced under mild conditions, over short reaction times, and in the presence of a wide variety of other protecting groups by the reaction of the 4,6-diol with triethyl (2-iodophenyl)orthoacetate and camphorsulfonic acid, followed by trimethylsilyl cyanide and boron trifluoride etherate. The new protecting group conveys strong beta-selectivity with thiomannoside donors and undergoes a tin-mediated radical fragmentation to provide high yields of the synthetically challenging beta-rhamnopyranosides. The method is also applicable to the glucopyranosides when high beta-selectivity is observed in the coupling reaction and alpha-quinovosides are formed selectively in the radical fragmentation step. In the galactopyranoside series, beta-glycosides are formed selectively on coupling to donors protected by the new system, but the radical fragmentation is unselective and gives mixtures of the 4- and 6-deoxy products. Variable-temperature NMR studies for the glycosylation step, which helped define an optimal protocol, are described.

  DOI：

  10.1021/jo0526688
• 作为产物：
  描述：

  S-ethyl 2,3-di-O-benzyl-4,6-O-(α-methoxycarbonyl)ethylidene-1-thio-α-D-mannopyranoside 在 三氟甲磺酸酐 molecular sieve 、 二苯基亚砜 、 2,4,5-tri-tert-butylpyrimidine 、 三甲基铝 作用下， 以 正己烷 、 二氯甲烷 、 甲苯 为溶剂， 反应 8.5h， 生成 methyl 4-O-(2,3-di-O-benzyl-4,6-O-[α-2-(2-iodophenyl)ethylthiocarbonyl]ethylidene-β-D-mannopyranosyl)-2,3-O-isopropylidene-α-L-rhamnopyranoside
  参考文献：
  名称：

  4,6-O-[1-Cyano-2-(2-iodophenyl)ethylidene] Acetals. Improved Second-Generation Acetals for the Stereoselective Formation of β-d-Mannopyranosides and Regioselective Reductive Radical Fragmentation to β-d-Rhamnopyranosides. Scope and Limitations

  摘要：

  The [1-cyano-2-(2-iodophenyl)]ethylidene group is introduced as an acetal-protecting group for carbohydrate thioglycoside donors. The group is easily introduced under mild conditions, over short reaction times, and in the presence of a wide variety of other protecting groups by the reaction of the 4,6-diol with triethyl (2-iodophenyl)orthoacetate and camphorsulfonic acid, followed by trimethylsilyl cyanide and boron trifluoride etherate. The new protecting group conveys strong beta-selectivity with thiomannoside donors and undergoes a tin-mediated radical fragmentation to provide high yields of the synthetically challenging beta-rhamnopyranosides. The method is also applicable to the glucopyranosides when high beta-selectivity is observed in the coupling reaction and alpha-quinovosides are formed selectively in the radical fragmentation step. In the galactopyranoside series, beta-glycosides are formed selectively on coupling to donors protected by the new system, but the radical fragmentation is unselective and gives mixtures of the 4- and 6-deoxy products. Variable-temperature NMR studies for the glycosylation step, which helped define an optimal protocol, are described.

  DOI：

  10.1021/jo0526688