2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-galactopyranosyl trichloroacetimidate | 616861-61-1

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-galactopyranosyl trichloroacetimidate
• 英文别名: Bz(-2)[Bn(-3)][Bn(-4)][Bn(-6)]Gal(a)-O-C(NH)CCl3；[(2R,3R,4S,5S,6R)-4,5-bis(phenylmethoxy)-6-(phenylmethoxymethyl)-2-(2,2,2-trichloroethanimidoyl)oxyoxan-3-yl] benzoate
• CAS: 616861-61-1
• 化学式: C₃₆H₃₄Cl₃NO₇
• 分子量: 699.027
• InChiKey: AHWNPSJPXORJSA-BWMDDLPLSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  7.7
• 重原子数：
  47
• 可旋转键数：
  15
• 环数：
  5.0
• sp3杂化的碳原子比例：
  0.28
• 拓扑面积：
  96.3
• 氢给体数：
  1
• 氢受体数：
  8

反应信息

• 作为反应物：
  描述：

  2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-galactopyranosyl trichloroacetimidate 在 氢氧化钾 、 三氟甲磺酸三甲基硅酯 作用下， 以 乙醚 、 乙醇 、 二氯甲烷 、 水 为溶剂， 反应 36.0h， 生成 methyl (3,4,6-tri-O-benzyl-β-D-galactopyranosyl)-(1->2)-(allyl 3,4-di-O-methoxymethyl-β-D-glucopyranosid)uronate
  参考文献：
  名称：

  Synthesis of the trisaccharide portion of soyasaponin βg: evaluation of a new glucuronic acid acceptor

  摘要：

  The synthesis of the trisaccharide portion of soyasaponin betag was successfully achieved using a new glucuronic acid acceptor: methyl 1-O-allyl-3 4-di-O-methoxymethyl-beta-D-glucuronate (9). This compound and methyl 1-O-allyl-3,4-di-O-tert-butyldimethyl-silyl-beta-D-glucuronate (8) were both prepared from glucuronolactone via a glycal intermediate. The former compound 9 was successfully coupled to ethyl 2-O-benzoyl-3,4,6-tri-O-benzyl-1-thio-beta-D-galactopyranoside (13) in excellent yield. Synthesis of the protected trisaccharide was then completed by the addition of a suitably protected rhamnose derivative to the disaccharide portion. The reactivity of the glucuronic acid derivative 9 was also explored with trichloroacetimidate and fluoride donors. (C) 2003 Elsevier Science Ltd. All rights reserved.

  DOI：

  10.1016/s0008-6215(03)00195-2
• 作为产物：
  描述：

  allyl 3,4,6-tri-O-benzyl-β-D-galactopyranoside 在 palladium dichloride 吡啶 、 水 、 sodium acetate 、 sodium 、 溶剂黄146 作用下， 以 二氯甲烷 为溶剂， 反应 2.0h， 生成 2-O-benzoyl-3,4,6-tri-O-benzyl-α-D-galactopyranosyl trichloroacetimidate
  参考文献：
  名称：

  Is acyl migration to the aglycon avoidable in 2-acyl assisted glycosylation reactions?

  摘要：

  这份报告首次明确区分了正酯醚的形成和酰基转移，并指出了在糖基化反应中消除2-O-酰基转移的可能途径。实验证据表明，从2-O-酰基-3,4,6-三-O-苄基-D-半乳糖苷供体中的酰基转移按照甲酰 > 乙酰 > 皮酰的顺序递减。2-O-苯甲酰衍生物更为多变，在某些情况下易于转移，而在其他情况下则不会转移。密度泛函理论（DFT）计算了二氧环离子及相关中间体的结构和能量学，表明从亲核试剂到O-2的质子转移途径解释了观察到的趋势。这些DFT计算的质子转移途径支持了一个涉及继电分子的机制。进一步的DFT计算使用基于六个键长的线性组合的约束来建立键断裂和键形成的顺序。在酰基转移过程中断裂的异常碳到前羰基氧键，在甲酰情况下是最长的，在几乎没有酰基转移的情况下是最短的。芳香环到羰基Ph-C(=O)键的旋转与烷基系列不同。对这个提出的过渡态的分析导致了这样一个假设，即2,6-取代可能会更加阻碍旋转。因此，合成了2,6-二甲基苯甲酰类似物，它不会直接转移，也不会通过其容易形成的正酯醚的重排转移。DFT计算表明，2,6-二甲氧基苯甲酰也不会轻易转移。实验上证明了这一点，这种新的2-O-酰基保护基在甲醇中与1mol/L的氢氧化锂溶液在50°C下裂解。因此，计算出的过渡态导致了一种解决寡糖合成中主要问题的保护基的原型。关键词：糖基化、碳水化合物、量子化学、反应机理、邻基效应。

  DOI：

  10.1139/v04-059

文献信息

• Is acyl migration to the aglycon avoidable in 2-acyl assisted glycosylation reactions?
  作者：Attila Bérces、Dennis M Whitfield、Tomoo Nukada、Iwona do Santos Z.、Agnes Obuchowska、Jiri J Krepinsky

  DOI：10.1139/v04-059

  日期：2004.7.1

  This report unequivocally separates orthoester formation from acyl transfer for the first time and indicates possible routes to eliminate 2-O-acyl transfer during glycosylation reactions. Experimental evidence is shown that acyl transfer from 2-O-acyl-3,4,6-tri-O-benzyl-D-galactopyranose-derived glycosyl donors decreases in the order formyl > acetyl > pivaloyl. The 2-O-benzoyl derivatives are more variable, in some cases transferring easily, and in others not at all. Density functional theory (DFT) calculations of the structure and energetics of dioxolenium ion and related intermediates suggest that a proton transfer pathway from the nucleophile to O-2 provides an explanation for the observed trends. These DFT calculations of the proton transfer pathway support a mechanism in which a relay molecule is involved. Further DFT calculations used a constraint based on linear combinations of six bond lengths to establish the sequence of bond breaking and bond forming. The calculated anomeric carbon to former carbonyl oxygen bond that breaks during acyl transfer is the longest in the formyl case and shortest in those that exhibit little or no acyl transfer. Rotation about the aromatic to carbonyl Ph—C(=O) bond is different from the alkyl series. Analysis of this proposed TS led to the postulate that 2,6-substitution may hinder rotation even more. Thus, the 2,6-dimethylbenzoyl analogue was synthesized and it does not transfer directly or by rearrangement of its readily formed orthoester. DFT calculations suggested that 2,6-dimethoxybenzoyl should also not transfer easily. Experimentally, this proved to be the case and this new 2-O-acyl protecting group cleaves at 50 °C with a 1 mol/L solution of LiOH in methanol. Thus, a calculated transition state has led to a prototype of a protecting group that solves a major problem in oligosaccharide synthesis.Key words: glycosylation, carbohydrates, quantum chemistry, reaction mechanism, neighboring-group effects.

  这份报告首次明确区分了正酯醚的形成和酰基转移，并指出了在糖基化反应中消除2-O-酰基转移的可能途径。实验证据表明，从2-O-酰基-3,4,6-三-O-苄基-D-半乳糖苷供体中的酰基转移按照甲酰 > 乙酰 > 皮酰的顺序递减。2-O-苯甲酰衍生物更为多变，在某些情况下易于转移，而在其他情况下则不会转移。密度泛函理论（DFT）计算了二氧环离子及相关中间体的结构和能量学，表明从亲核试剂到O-2的质子转移途径解释了观察到的趋势。这些DFT计算的质子转移途径支持了一个涉及继电分子的机制。进一步的DFT计算使用基于六个键长的线性组合的约束来建立键断裂和键形成的顺序。在酰基转移过程中断裂的异常碳到前羰基氧键，在甲酰情况下是最长的，在几乎没有酰基转移的情况下是最短的。芳香环到羰基Ph-C(=O)键的旋转与烷基系列不同。对这个提出的过渡态的分析导致了这样一个假设，即2,6-取代可能会更加阻碍旋转。因此，合成了2,6-二甲基苯甲酰类似物，它不会直接转移，也不会通过其容易形成的正酯醚的重排转移。DFT计算表明，2,6-二甲氧基苯甲酰也不会轻易转移。实验上证明了这一点，这种新的2-O-酰基保护基在甲醇中与1mol/L的氢氧化锂溶液在50°C下裂解。因此，计算出的过渡态导致了一种解决寡糖合成中主要问题的保护基的原型。关键词：糖基化、碳水化合物、量子化学、反应机理、邻基效应。
• Synthesis of the trisaccharide portion of soyasaponin βg: evaluation of a new glucuronic acid acceptor
  作者：Karen Plé

  DOI：10.1016/s0008-6215(03)00195-2

  日期：2003.7

  The synthesis of the trisaccharide portion of soyasaponin betag was successfully achieved using a new glucuronic acid acceptor: methyl 1-O-allyl-3 4-di-O-methoxymethyl-beta-D-glucuronate (9). This compound and methyl 1-O-allyl-3,4-di-O-tert-butyldimethyl-silyl-beta-D-glucuronate (8) were both prepared from glucuronolactone via a glycal intermediate. The former compound 9 was successfully coupled to ethyl 2-O-benzoyl-3,4,6-tri-O-benzyl-1-thio-beta-D-galactopyranoside (13) in excellent yield. Synthesis of the protected trisaccharide was then completed by the addition of a suitably protected rhamnose derivative to the disaccharide portion. The reactivity of the glucuronic acid derivative 9 was also explored with trichloroacetimidate and fluoride donors. (C) 2003 Elsevier Science Ltd. All rights reserved.