3-O-[2,3-di-O-benzyl-4,6-O-(1-cyano)ethylidene-β-D-mannopyranosyl]-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 3-O-[2,3-di-O-benzyl-4,6-O-(1-cyano)ethylidene-β-D-mannopyranosyl]-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose
• 英文别名: (2S,4aR,6S,7S,8S,8aR)-6-[[(3aR,5R,6S,6aR)-5-[(4R)-2,2-dimethyl-1,3-dioxolan-4-yl]-2,2-dimethyl-3a,5,6,6a-tetrahydrofuro[2,3-d][1,3]dioxol-6-yl]oxy]-2-methyl-7,8-bis(phenylmethoxy)-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxine-2-carbonitrile
• 化学式: C₃₅H₄₃NO₁₁
• 分子量: 653.727
• InChiKey: SIVHZZSXDMCYBE-SMSRVQFOSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.9
• 重原子数：
  47
• 可旋转键数：
  9
• 环数：
  7.0
• sp3杂化的碳原子比例：
  0.63
• 拓扑面积：
  125
• 氢给体数：
  0
• 氢受体数：
  12

反应信息

• 作为产物：
  描述：

  S-phenyl 2,3-di-O-benzyl-α-D-thiomannopyranoside 在 三氟甲磺酸酐 molecular sieve 、 二苯基亚砜 、 2,4,5-tri-tert-butylpyrimidine 、 camphor-10-sulfonic acid 、 三氟化硼乙醚 作用下， 以 二氯甲烷 为溶剂， 反应 7.0h， 生成 3-O-[2,3-di-O-benzyl-4,6-O-(1-cyano)ethylidene-β-D-mannopyranosyl]-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose
  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

文献信息

• 4,6-<i>O</i>-[1-Cyano-2-(2-iodophenyl)ethylidene] Acetals. Improved Second-Generation Acetals for the Stereoselective Formation of β-<scp>d</scp>-Mannopyranosides and Regioselective Reductive Radical Fragmentation to β-<scp>d</scp>-Rhamnopyranosides. Scope and Limitations
  作者：David Crich、Albert A. Bowers

  DOI：10.1021/jo0526688

  日期：2006.4.1

  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.