7-Bromo-6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene

• 分子结构分类: 有机化合物 - 有机硫化合物 - 硫代缩醛
• 英文名称: 7-Bromo-6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene
• 化学式: C₉H₁₃BrOS
• 分子量: 249.172
• InChiKey: SKCBFTBORBTGDX-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.2
• 重原子数：
  12
• 可旋转键数：
  0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.78
• 拓扑面积：
  34.5
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  7-Bromo-6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene 在 正丁基锂 、 18-冠醚-6 、 potassium hydride 作用下， 以 四氢呋喃 、 正己烷 为溶剂， 反应 1.17h， 生成 (5R,6R,7R)-6-Allyl-6-methyl-1-oxa-4-thia-spiro[4.5]decane-7-carbaldehyde
  参考文献：
  名称：

  The suitability of anion-accelerated oxy-Cope rearrangement as a probe to study π-facial selectivity. An experimental study with (6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-en-7-yl)(allyl)methanols †

  摘要：

  在四氢呋喃、苯和二甲醚等溶剂中，对[(6-甲基-1-氧杂-4-硫杂螺[4.5]癸-6-烯-7-基)(烯丙基)甲醇进行阴离子加速氧-科普重排，以评估缩醛功能引起的Ï-面选择性。非对映异构体对 17a 和 17b（R =  Ph）产生了相同的两种非对映异构产物 18a 和 18b，区别仅在于相对优势度不同。在四氢呋喃中，17a 的反应从大部分与氧（18aâ¶18b = 1¶4）同向转变为在二甲醚中与硫中度同向（18aâ¶18b = 2.2¶1）。该反应在苯中完全无选择性。溶剂对 17b 反应的影响更为有趣。在四氢呋喃中，反应完全无选择性（18aâ¶18b = 1¶1），而在二甲醚中，反应则与硫高度同步（18aâ¶18b = 5.4¶1）。在苯中的选择性介于两者之间（18a¶18b = 2.7¶1）。同样，17b（R = H）在四氢呋喃中对氧的反应由中度同步（18a¶18b = 1¶2）变为在二甲醚中几乎无选择性（18a¶18b = 1¶1.1）。围绕甲醇碳和相邻环碳之间的键的旋转受到限制，在 17a 中只能发生硫的同义重排，在 17b 中只能发生氧的同义重排。所观察到的非对映选择性的显著减弱是由于自由基和/或离子型逆醛酸结合过程造成的。不过，自由基途径比离子途径更为普遍。重组在一定程度上有利于烯丙基与硫的合成面上生成的 7-苯甲酰基-6-甲基-1-氧杂-4-硫杂螺[4.5]癸-6-烯相加。由于这种解离和重组，氧-科普重排似乎不适合作为研究非对映选择性的探针。

  DOI：

  10.1039/a909839i

文献信息

• An Investigation of the Diastereoselectivity of Nucleophilic Additions to 6-Methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene-7-carbaldehyde. Hybridization of the Nucleophile Alters the Diastereoselectivity
  作者：Duraiswamy A. Jeyaraj、Veejendra K. Yadav、Masood Parvez、Harsh M. Gauniyal

  DOI：10.1021/jo971697i

  日期：1998.6.1

  6-Methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene-7-carbaldehyde was treated with a variety of nucleophiles under varying conditions. Whereas the 1,4-diastereoselectivity observed with sp(3) nucleophiles was more or less 1.0:1.1 in favor of attack anti to sulfur, sp(2) and sp nucleophiles exhibited relatively much improved but reversed pi-selection under the same conditions. The highest selectivity observed was 3.5:1.0 in favor of attack syn to sulfur in reaction with PhMgBr in Et2O at -80 degrees C. This selectivity was reduced to 1.6:1.0 when the reaction was conducted in a 9:1 mixture of Et2O and HMPA but enhanced to 7.2:1.0 when the polarity of the reaction medium was reduced by conducting the reaction in a 1:1 mixture of Et2O and n-hexane. Neither the anti to S nor the syn to S diastereoselectivity obeyed the dipole model reported by Wipf and Kim. The syn to S selectivity in reactions with sp(2) and sp nucleophiles may be a result of significant and yet specific electrostatic attraction of S for these nucleophilic species which have their negative charges concentrated largely on the carbon for their known significant polar characters.
• The suitability of anion-accelerated oxy-Cope rearrangement as a probe to study π-facial selectivity. An experimental study with (6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-en-7-yl)(allyl)methanols †
  作者：Veejendra K. Yadav、Duraiswamy A. Jeyaraj、Masood Parvez

  DOI：10.1039/a909839i

  日期：——

  [(6-Methyl-1-oxa-4-thiaspiro[4.5]dec-6-en-7-yl)(allyl)methanols were subjected to anion-accelerated oxy-Cope rearrangement in solvents such as THF, benzene and DME to assess the π-facial selectivity caused by the acetal function. The diastereomeric pairs 17a and 17b (R = Ph) furnished the same two diastereomeric products 18a and 18b, differing only in the relative preponderance. The reaction of 17a turned from mostly syn to oxygen (18a∶18b = 1∶4) in THF to moderately syn to sulfur (18a∶18b = 2.2∶1) in DME. The reaction was completely nonselective in benzene. The effect of solvent on the reaction of 17b was even more interesting. The reaction turned from completely nonselective (18a∶18b = 1∶1) in THF to highly syn to sulfur (18a∶18b = 5.4∶1) in DME. The selectivity in benzene was somewhere in between (18a∶18b = 2.7∶1). Likewise, the reaction of 17b (R = H) turned from moderately syn to oxygen in THF (18a∶18b = 1∶2) to nearly nonselective in DME (18a∶18b = 1∶1.1). The rotation around the bond between the methanol carbon and the adjacent ring-carbon is restricted to allow rearrangement only syn to sulfur in 17a and syn to oxygen in 17b. The considerable erosion in the observed diastereoselectivity is due to a radical and/or ionic retroaldol–recombination process. The radical pathway, however, is more prevalent than the ionic alternative. The recombination favors somewhat the addition of the allyl radical to the cogenerated 7-benzoyl-6-methyl-1-oxa-4-thiaspiro[4.5]dec-6-ene on the face syn to the sulfur. As a result of such dissociation and recombination, the oxy-Cope rearrangement does not appear suitable as a probe for the study of diastereofacial selectivity.

  在四氢呋喃、苯和二甲醚等溶剂中，对[(6-甲基-1-氧杂-4-硫杂螺[4.5]癸-6-烯-7-基)(烯丙基)甲醇进行阴离子加速氧-科普重排，以评估缩醛功能引起的Ï-面选择性。非对映异构体对 17a 和 17b（R =  Ph）产生了相同的两种非对映异构产物 18a 和 18b，区别仅在于相对优势度不同。在四氢呋喃中，17a 的反应从大部分与氧（18aâ¶18b = 1¶4）同向转变为在二甲醚中与硫中度同向（18aâ¶18b = 2.2¶1）。该反应在苯中完全无选择性。溶剂对 17b 反应的影响更为有趣。在四氢呋喃中，反应完全无选择性（18aâ¶18b = 1¶1），而在二甲醚中，反应则与硫高度同步（18aâ¶18b = 5.4¶1）。在苯中的选择性介于两者之间（18a¶18b = 2.7¶1）。同样，17b（R = H）在四氢呋喃中对氧的反应由中度同步（18a¶18b = 1¶2）变为在二甲醚中几乎无选择性（18a¶18b = 1¶1.1）。围绕甲醇碳和相邻环碳之间的键的旋转受到限制，在 17a 中只能发生硫的同义重排，在 17b 中只能发生氧的同义重排。所观察到的非对映选择性的显著减弱是由于自由基和/或离子型逆醛酸结合过程造成的。不过，自由基途径比离子途径更为普遍。重组在一定程度上有利于烯丙基与硫的合成面上生成的 7-苯甲酰基-6-甲基-1-氧杂-4-硫杂螺[4.5]癸-6-烯相加。由于这种解离和重组，氧-科普重排似乎不适合作为研究非对映选择性的探针。