1-methyl-4α-bromo-2α-phthalimido-8-oxabicyclo<3.2.1>oct-6-en-3-one

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 异吲哚及其衍生物
• 英文名称: 1-methyl-4α-bromo-2α-phthalimido-8-oxabicyclo<3.2.1>oct-6-en-3-one
• 英文别名: 2-[(1S,2R,4S,5R)-4-bromo-1-methyl-3-oxo-8-oxabicyclo[3.2.1]oct-6-en-2-yl]isoindole-1,3-dione
• 化学式: C₁₆H₁₂BrNO₄
• 分子量: 362.18
• InChiKey: FWTNIWFGBXBPCB-IZBNFRDHSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.7
• 重原子数：
  22
• 可旋转键数：
  1
• 环数：
  4.0
• sp3杂化的碳原子比例：
  0.31
• 拓扑面积：
  63.7
• 氢给体数：
  0
• 氢受体数：
  4

反应信息

• 作为产物：
  描述：

  2-甲基呋喃 、 α,α'-phthalimidoyl dibromide 在 lithium perchlorate 、 三乙胺 作用下， 以 乙腈 为溶剂， 生成 1-methyl-4α-bromo-2α-phthalimido-8-oxabicyclo<3.2.1>oct-6-en-3-one 、 1-methyl-2α-bromo-4β-phthalimido-8-oxabicyclo[3.2.1]oct-6-en-3-one 、 1-methyl-2α-bromo-4α-phthalimido-8-oxabicyclo[3.2.1]oct-6-en-3-one
  参考文献：
  名称：

  Cycloaddition Reactions of a Nitrogen-Substituted Oxyallyl Cation with Cyclopentadiene and Substituted Furans. Reaction Conditions, Diastereoselectivity, Regioselectivity, and Transition State Modeling

  摘要：

  An investigation of the cycloaddition reactions of a nitrogen-substituted oxyallyl cation is presented. The nitrogen-substituted oxyallyl cation, M(+)-1 (M(+) = H+ or Li+), can be generated from the dibromide 2 using either CF3CH2OH/Et(3)N or LiClO4/CH3CN/Et(3)N. These oxyallyl cations were found to undergo [4 + 2] cycloaddition reactions with furan, cyclopentadiene, 2-methylfuran, and 2-methoxyfuran. The diastereo- and regioselectivities in these reactions were found to be positively influenced by the presence of Li+. Reaction of M(+)-1 with the 2-substituted furans led to primarily those adducts arising from endo addition (as was observed with the unsubstituted dienes) and which had the 2-substituent syn to the bromine. Consideration of the frontier molecular orbitals of the reacting species (Li+-1 and 2-substituted furans calculated at the PM3 semiempirical level of theory) led to the conclusion that FMO theory does not explain the regiochemistry observed in this process, although the relative electrophilicity of M(+)-1 (M(+) = H+ or Li+) could be rationalized. Transition structure modeling was consistent with empirical observations in that it predicted an endo addition of furan to Li+-1 via a stepwise reaction. Calculation of the reaction coordinate for this nonconcerted process predicted a Delta H-rxn similar to -50 kcals/mol and Delta H-act similar to +11 kcal/mol, with the second bond-forming process having a Delta H-act similar to +1.7 kcal/mol.

  DOI：

  10.1021/jo951609z

文献信息

• Cycloaddition Reactions of a Nitrogen-Substituted Oxyallyl Cation with Cyclopentadiene and Substituted Furans. Reaction Conditions, Diastereoselectivity, Regioselectivity, and Transition State Modeling
  作者：Michael A. Walters、Helene R. Arcand

  DOI：10.1021/jo951609z

  日期：1996.1.1

  An investigation of the cycloaddition reactions of a nitrogen-substituted oxyallyl cation is presented. The nitrogen-substituted oxyallyl cation, M(+)-1 (M(+) = H+ or Li+), can be generated from the dibromide 2 using either CF3CH2OH/Et(3)N or LiClO4/CH3CN/Et(3)N. These oxyallyl cations were found to undergo [4 + 2] cycloaddition reactions with furan, cyclopentadiene, 2-methylfuran, and 2-methoxyfuran. The diastereo- and regioselectivities in these reactions were found to be positively influenced by the presence of Li+. Reaction of M(+)-1 with the 2-substituted furans led to primarily those adducts arising from endo addition (as was observed with the unsubstituted dienes) and which had the 2-substituent syn to the bromine. Consideration of the frontier molecular orbitals of the reacting species (Li+-1 and 2-substituted furans calculated at the PM3 semiempirical level of theory) led to the conclusion that FMO theory does not explain the regiochemistry observed in this process, although the relative electrophilicity of M(+)-1 (M(+) = H+ or Li+) could be rationalized. Transition structure modeling was consistent with empirical observations in that it predicted an endo addition of furan to Li+-1 via a stepwise reaction. Calculation of the reaction coordinate for this nonconcerted process predicted a Delta H-rxn similar to -50 kcals/mol and Delta H-act similar to +11 kcal/mol, with the second bond-forming process having a Delta H-act similar to +1.7 kcal/mol.