methyl (phenyl 2-O-benzyl-3,4-O-[2',3'-dimethoxybutane-2',3'-diyl]-1-thio-β-D-mannopyranosyluronate) | 1158840-53-9

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: methyl (phenyl 2-O-benzyl-3,4-O-[2',3'-dimethoxybutane-2',3'-diyl]-1-thio-β-D-mannopyranosyluronate)
• 英文别名: methyl (2S,3S,4aS,5S,7S,8S,8aS)-2,3-dimethoxy-2,3-dimethyl-8-phenylmethoxy-7-phenylsulfanyl-5,7,8,8a-tetrahydro-4aH-pyrano[3,4-b][1,4]dioxine-5-carboxylate
• CAS: 1158840-53-9
• 化学式: C₂₆H₃₂O₈S
• 分子量: 504.601
• InChiKey: GNEQWGINCJSRSV-OQHHGKSNSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.6
• 重原子数：
  35
• 可旋转键数：
  9
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  107
• 氢给体数：
  0
• 氢受体数：
  9

反应信息

• 作为反应物：
  描述：

  methyl (methyl 2,3-di-O-benzyl-α-D-mannopyranosyluronate) 、 methyl (phenyl 2-O-benzyl-3,4-O-[2',3'-dimethoxybutane-2',3'-diyl]-1-thio-β-D-mannopyranosyluronate) 在 三氟甲磺酸酐 、 二苯基亚砜 、 2,4,6-三叔丁基嘧啶 作用下， 以 二氯甲烷 为溶剂， 反应 0.25h， 以24%的产率得到methyl 2,3-di-O-benzyl-4-O-[methyl (ethyl 2-O-benzyl-3,4-O-[2',3'-dimethoxybutane-2',3'-diyl]-α-D-mannopyranosyluronate)]-α-D-mannopyranosyluronate
  参考文献：
  名称：

  Stereoselectivity of glycosylations of conformationally restricted mannuronate esters

  摘要：

  Glycosidation of conformationally unrestricted mannuronate ester donors proceeds in a highly P-selective fashion, whereas condensations of mannuronate ester donors, which are con formationally constrained by a 3,4-butanedimethylacetal or a 2,3-isopropylidene function, provide a-selective products. We hypothesize that the difference in stereochemical outcome of these condensations results from the different conformations of the product forming oxacarbenium intermediate. The formation of the beta-linked products from the flexible mannuronates is thought to originate from the most favorable H-3(4) oxacarbenium ion, which is not accessible from the conformationally restrained donors. Although an a-triflate intermediate is formed upon activation of the 3,4-butanedimethylacetal protected mannuronate ester thio donor, this is not the product forming intermediate. The anomeric triflate serves as a reservoir for the H-4(3) oxacarbenium ion, which is glycosidated to provide the a-linked mannuronates. (C) 2009 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tet.2009.02.067
• 作为产物：
  描述：

  、 三甲基硅烷化重氮甲烷 以 正己烷 、 二氯甲烷 为溶剂， 反应 0.08h， 以374 mg的产率得到methyl (phenyl 2-O-benzyl-3,4-O-[2',3'-dimethoxybutane-2',3'-diyl]-1-thio-β-D-mannopyranosyluronate)
  参考文献：
  名称：

  Stereoselectivity of glycosylations of conformationally restricted mannuronate esters

  摘要：

  Glycosidation of conformationally unrestricted mannuronate ester donors proceeds in a highly P-selective fashion, whereas condensations of mannuronate ester donors, which are con formationally constrained by a 3,4-butanedimethylacetal or a 2,3-isopropylidene function, provide a-selective products. We hypothesize that the difference in stereochemical outcome of these condensations results from the different conformations of the product forming oxacarbenium intermediate. The formation of the beta-linked products from the flexible mannuronates is thought to originate from the most favorable H-3(4) oxacarbenium ion, which is not accessible from the conformationally restrained donors. Although an a-triflate intermediate is formed upon activation of the 3,4-butanedimethylacetal protected mannuronate ester thio donor, this is not the product forming intermediate. The anomeric triflate serves as a reservoir for the H-4(3) oxacarbenium ion, which is glycosidated to provide the a-linked mannuronates. (C) 2009 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tet.2009.02.067

文献信息

• The impact of oxacarbenium ion conformers on the stereochemical outcome of glycosylations
  作者：Marthe T.C. Walvoort、Jasper Dinkelaar、Leendert J. van den Bos、Gerrit Lodder、Herman S. Overkleeft、Jeroen D.C. Codée、Gijsbert A. van der Marel

  DOI：10.1016/j.carres.2010.02.027

  日期：2010.7

  The search for stereoselective glycosylation reactions has occupied synthetic carbohydrate chemists for decades. Traditionally, most attention has been focused on controlling the S(N)2-like substitution of anomeric leaving groups as highlighted by Lemieux's in situ anomerization protocol and by the discovery of anomeric triflates as reactive intermediates in the stereoselective formation of beta-mannosides

  立体选择性糖基化反应的研究已经占据了合成碳水化合物化学家的数十年。传统上，大多数注意力都集中在控制异头离去基团的S（N）2取代上，如Lemieux的原位异构化方案和发现异头三氟甲磺酸酯作为β-甘露糖苷立体选择性形成中的反应性中间体所强调的那样。近来，已经清楚的是，类似S（N）1的反应途径也可以导致高度选择性的糖基化反应。这篇综述描述了立体选择性糖基化的一些最新实例，其中氧杂碳鎓离子被认为是选择性的基础。