(S)-N-(3-bromopropyl)-N-(tert-butoxycarbonyl)methionine ethyl ester | 619307-02-7

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: (S)-N-(3-bromopropyl)-N-(tert-butoxycarbonyl)methionine ethyl ester
• 英文别名: (S)-N-(3-bromo-propyl)-N-(tert-butoxycarbonyl) methionine；ethyl (2S)-2-[3-bromopropyl-[(2-methylpropan-2-yl)oxycarbonyl]amino]-4-methylsulfanylbutanoate
• CAS: 619307-02-7
• 化学式: C₁₅H₂₈BrNO₄S
• 分子量: 398.362
• InChiKey: LTIXEEHINPBQID-LBPRGKRZSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.6
• 重原子数：
  22
• 可旋转键数：
  12
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.87
• 拓扑面积：
  81.1
• 氢给体数：
  0
• 氢受体数：
  5

反应信息

• 作为反应物：
  描述：

  (S)-N-(3-bromopropyl)-N-(tert-butoxycarbonyl)methionine ethyl ester 在 双(三甲基硅烷基)氨基钾 作用下， 以 四氢呋喃 、 N,N-二甲基甲酰胺 为溶剂， 反应 0.5h， 以92%的产率得到N-(tert-butoxycarbonyl)-α-(2-methylthioethyl)proline ethyl ester
  参考文献：
  名称：

  通过手性记忆的不对称环化：用四元立体中心简明获得环状氨基酸

  摘要：

  N-(ω-溴烷基)-氨基酸衍生物，很容易从天然α-氨基酸制备，通过在DMF中用六甲基二硅氮杂钾处理得到具有季立体中心的环状氨基酸。在烯醇化物形成和环化过程中，亲本氨基酸的手性几乎完全保留，使氮杂环氨基酸的构型保留率高达 98% ee。该方法适用于氮杂环丁烷、吡咯烷、哌啶和氮杂环庚烷衍生物的不对称合成。不对称环化似乎是通过轴向手性烯醇中间体而不是通过协调一致的 SEi 过程进行的。

  DOI：

  10.1021/ja0378299

文献信息

• Stereochemical Diversity in Asymmetric Cyclization via Memory of Chirality
  作者：Takeo Kawabata、Seiji Matsuda、Shimpei Kawakami、Daiki Monguchi、Katsuhiko Moriyama

  DOI：10.1021/ja0670761

  日期：2006.12.1

  potassium amide bases in DMF, cyclization proceeds with retention of configuration, while inversion of configuration was observed with lithium amide bases in THF. Chirality of the parent amino acids was preserved during enolate formation and cyclization to give aza-cyclic amino acids in up to 98% ee with retention of configuration or inversion of configuration, depending on the reaction conditions. Thus, both

  已开发出 N-Boc-N-ω-溴烷基-α-氨基酸衍生物的对映发散不对称环化。在 DMF 中使用氨基钾碱时，环化在构型保留的情况下进行，而在 THF 中使用氨基化锂碱时观察到构型反转。在烯醇化物形成和环化过程中保留了母体氨基酸的手性，以产生高达 98% ee 的氮杂环氨基酸，并保留构型或反转构型，这取决于反应条件。因此，具有四取代立体中心的环状氨基酸的两种对映异构体均以高对映异构纯度从容易获得的l-α-氨基酸制备。该协议也适用于α-氨基酸衍生物的螺环化和分子内共轭添加，
• Powdered KOH in DMSO:  An Efficient Base for Asymmetric Cyclization via Memory of Chirality at Ambient Temperature
  作者：Takeo Kawabata、Katsuhiko Moriyama、Shimpei Kawakami、Kazunori Tsubaki

  DOI：10.1021/ja077684w

  日期：2008.3.1

  Enolate chemistry has been extensively used for stereoselective C-C bond formation, in which metal amide bases are frequently employed in strictly anhydrous solvents at low temperatures. However, we found that asymmetric intramolecular C-C bond formation via axially chiral enolate intermediates proceeded in up to 99% ee at 20 degrees C using powdered KOH in dry or wet DMSO as a base. The enantioselectivity was even higher than that of the corresponding reactions with potassium hexamethyldisilazide in DIVIF at -60 degrees C. The racemization barrier of the axially chiral enolate intermediate was estimated to be similar to 15.5 kcal/mol. On the basis of the barrier, the chiral enolate intermediate was supposed to undergo cyclization within similar to 10(-3) sec at 20 degrees C after it is generated to give the product in 2 >= 99% ee. Thus, enolates generated with powdered KOH in DMSO were expected to be extremely reactive.