3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-β-L-rhamnopyranoside | 629627-37-8

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 类固醇和类固醇衍生物
• 英文名称: 3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-β-L-rhamnopyranoside
• 英文别名: (3aS,4S,6S,7R,7aR)-6-[[(3S,5S,8R,9S,10S,13R,14S,17R)-10,13-dimethyl-17-[(2R)-6-methylheptan-2-yl]-2,3,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-3-yl]oxy]-4-methyl-7-phenylmethoxy-4,6,7,7a-tetrahydro-3aH-[1,3]dioxolo[4,5-c]pyran-2-one
• CAS: 629627-37-8
• 化学式: C₄₁H₆₂O₆
• 分子量: 650.94
• InChiKey: ZAOHIKDIGDPFOY-VWGFZRICSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  11.7
• 重原子数：
  47
• 可旋转键数：
  10
• 环数：
  7.0
• sp3杂化的碳原子比例：
  0.83
• 拓扑面积：
  63.2
• 氢给体数：
  0
• 氢受体数：
  6

反应信息

• 作为反应物：
  描述：

  3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-β-L-rhamnopyranoside 在 sodium methylate 作用下， 以 甲醇 、 二氯甲烷 为溶剂， 反应 3.0h， 以81%的产率得到3β-cholestanyl 2-O-benzyl-β-L-rhamnopyranoside
  参考文献：
  名称：

  The 3,4-O-Carbonate Protecting Group as a β-Directing Group in Rhamnopyranosylation in Both Homogeneous and Heterogeneous Glycosylations As Compared to the Chameleon-like 2,3-O-Carbonates

  摘要：

  It is demonstrated that the beta-selectivity observed in the insoluble silver salt mediated couplings of 2,3-O-carbonate-protected rhamnosyl bromides is uniquely due to the heterogeneous nature of the reaction. In homogeneous solution these same donors are alpha-selective, a fact that is attributed to the half-chair conformation of these substances which reduces the energy barrier to oxacarbenium ion formation. It is suggested that the 2,3-O-carbonate group be dubbed torsionally arming in the manno- and rhamnopyranose series. When the carbonate group is removed to the 3,4-O-position a beta-selective system is formed, in both homogeneous and heterogeneous conditions, and it is demonstrated that this selectivity arises from the combination of the electron-withdrawing nature of the carbonate and its inability to take part in neighboring participation.

  DOI：

  10.1021/jo035003j
• 作为产物：
  描述：

  phenyl 2-O-benzyl-3,4-O-carbonyl-1-thio-β-L-rhamnopyranoside 在 溴 、 silver carbonate 作用下， 以 二氯甲烷 为溶剂， 反应 15.0h， 生成 3β-cholestanyl 2-O-benzyl-3,4-O-carbonyl-β-L-rhamnopyranoside
  参考文献：
  名称：

  The 3,4-O-Carbonate Protecting Group as a β-Directing Group in Rhamnopyranosylation in Both Homogeneous and Heterogeneous Glycosylations As Compared to the Chameleon-like 2,3-O-Carbonates

  摘要：

  It is demonstrated that the beta-selectivity observed in the insoluble silver salt mediated couplings of 2,3-O-carbonate-protected rhamnosyl bromides is uniquely due to the heterogeneous nature of the reaction. In homogeneous solution these same donors are alpha-selective, a fact that is attributed to the half-chair conformation of these substances which reduces the energy barrier to oxacarbenium ion formation. It is suggested that the 2,3-O-carbonate group be dubbed torsionally arming in the manno- and rhamnopyranose series. When the carbonate group is removed to the 3,4-O-position a beta-selective system is formed, in both homogeneous and heterogeneous conditions, and it is demonstrated that this selectivity arises from the combination of the electron-withdrawing nature of the carbonate and its inability to take part in neighboring participation.

  DOI：

  10.1021/jo035003j

文献信息

• The 3,4-<i>O</i>-Carbonate Protecting Group as a β-Directing Group in Rhamnopyranosylation in Both Homogeneous and Heterogeneous Glycosylations As Compared to the Chameleon-like 2,3-<i>O</i>-Carbonates
  作者：David Crich、A. U. Vinod、John Picione

  DOI：10.1021/jo035003j

  日期：2003.10.1

  It is demonstrated that the beta-selectivity observed in the insoluble silver salt mediated couplings of 2,3-O-carbonate-protected rhamnosyl bromides is uniquely due to the heterogeneous nature of the reaction. In homogeneous solution these same donors are alpha-selective, a fact that is attributed to the half-chair conformation of these substances which reduces the energy barrier to oxacarbenium ion formation. It is suggested that the 2,3-O-carbonate group be dubbed torsionally arming in the manno- and rhamnopyranose series. When the carbonate group is removed to the 3,4-O-position a beta-selective system is formed, in both homogeneous and heterogeneous conditions, and it is demonstrated that this selectivity arises from the combination of the electron-withdrawing nature of the carbonate and its inability to take part in neighboring participation.