| 1163254-65-6

• 分子结构分类: 有机化合物 - 有机氧化合物
• CAS: 1163254-65-6
• 化学式: C₃₄H₃₄O₆S
• 分子量: 570.706
• InChiKey: SKTIDYVTFMNJIC-YPJZNHGYSA-N

反应信息

• 作为反应物：
  描述：

  p-methoxyphenyl 2-O-benzyl-4,6-O-benzylidene-β-D-galactopyranoside 、 在 二苯基亚砜 、 2,4,6-三叔丁基嘧啶 、 三氟甲磺酸酐 作用下， 以 二氯甲烷 为溶剂， 反应 0.5h， 以52%的产率得到methyl (2S,3S,4R,5R,6S)-6-[[(2S,4aR,6S,7R,8S,8aS)-6-(4-methoxyphenoxy)-2-phenyl-7-phenylmethoxy-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxin-8-yl]oxy]-3,4,5-tris(phenylmethoxy)oxane-2-carboxylate
  参考文献：
  名称：

  Stereodirecting Effect of the Pyranosyl C-5 Substituent in Glycosylation Reactions

  摘要：

  The stereodirecting effect of the glycosyl C-5 substituent has been investigated in a series of D-pyranosyl thioglycoside donors and related to their preferred positions in the intermediate H-3(4) and H-4(3) half-chair oxacarbenium ions. Computational studies showed that an axially positioned C-5 carboxylate ester can stabilize the (3)H4 half-chair oxacarbenium ion conformer by donating electron densit from its carbonyl function into the electron-poor oxacarbenium ion functionality. A similar stabilization can be achieved by a C-5 benzyloxyrnethyl group, but,the magnitude of this stabilization is significantly smaller than for the C-5 carboxylate ester. As a result, the preference of the C-5 benzyloxymethyl to occupy an axial position in the half-chair oxacarbenium ions is much reduced compared to the C-5 carboxylate ester. To minimize steric interactions, a C-5 methyl group prefers to adopt an equatorial position and therefore favors the H-4(3) half-chair oxacarbenium ion. When all pyranosyl substituents occupy their favored position in one of the two intermediate half-chair oxacarbenium ions, highly stereoselective glycosylations can be achieved as revealed by the excellent beta-selectivity of mannuronate esters and alpha-selectivity of 6-deoxygulosides.

  DOI：

  10.1021/jo900662v
• 作为产物：
  描述：

  、 碘甲烷 在 potassium carbonate 作用下， 以 N,N-二甲基甲酰胺 为溶剂， 以1.30 g的产率得到
  参考文献：
  名称：

  Stereodirecting Effect of the Pyranosyl C-5 Substituent in Glycosylation Reactions

  摘要：

  The stereodirecting effect of the glycosyl C-5 substituent has been investigated in a series of D-pyranosyl thioglycoside donors and related to their preferred positions in the intermediate H-3(4) and H-4(3) half-chair oxacarbenium ions. Computational studies showed that an axially positioned C-5 carboxylate ester can stabilize the (3)H4 half-chair oxacarbenium ion conformer by donating electron densit from its carbonyl function into the electron-poor oxacarbenium ion functionality. A similar stabilization can be achieved by a C-5 benzyloxyrnethyl group, but,the magnitude of this stabilization is significantly smaller than for the C-5 carboxylate ester. As a result, the preference of the C-5 benzyloxymethyl to occupy an axial position in the half-chair oxacarbenium ions is much reduced compared to the C-5 carboxylate ester. To minimize steric interactions, a C-5 methyl group prefers to adopt an equatorial position and therefore favors the H-4(3) half-chair oxacarbenium ion. When all pyranosyl substituents occupy their favored position in one of the two intermediate half-chair oxacarbenium ions, highly stereoselective glycosylations can be achieved as revealed by the excellent beta-selectivity of mannuronate esters and alpha-selectivity of 6-deoxygulosides.

  DOI：

  10.1021/jo900662v