methyl (3R)-3-ethyl-4-methylpentanoate | 79194-61-9

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 脂肪酰基
• 英文名称: methyl (3R)-3-ethyl-4-methylpentanoate
• 英文别名: (R)-(-)-methyl 3-ethyl-4-methylpentanoate；Methyl (r)-3-ethyl-4-methylpentanoate
• CAS: 79194-61-9
• 化学式: C₉H₁₈O₂
• 分子量: 158.241
• InChiKey: TWZULJKZBGIFOI-MRVPVSSYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.7
• 重原子数：
  11
• 可旋转键数：
  5
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.89
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  (20S)-20-(iodomethyl)-4α-methyl-5α-pregnane 、 methyl (3R)-3-ethyl-4-methylpentanoate 生成 (20R,23ξ,24S)-4α-methyl-5α-stigmastane-23-carboxylic acid
  参考文献：
  名称：

  Synthesis of biological markers in fossil fuels. 7. Selected diastereomers of 4.alpha.-methyl-5.alpha.-stigmastane and 5.alpha.-dinosterane

  摘要：

  Efficient routes for the preparation of selected C-23 and C-24 diastereomers of the C30 biological markers 4alpha-methyl-5alpha-stigmastane (1) and 5alpha-dinosterane (2) involved the alkylation of 20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with either saturated or alpha,beta-unsaturated esters. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3R)-3-ethyl-4-methylpentanoate furnished methyl (20R,23zeta,24S)-4alpha-methyl-5alpha-stigmastane-23-carboxylate, and a subsequent decarbomethoxylation provided (20R,24R)-l. The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (3S)-3,4-dimethylpentanoate led to methyl (20R,23zeta,24R)-4alpha,24-dimethyl-5alpha-cholestane-23-carboxylate, and the reduction of this mixture provided principally (20R,23S,24R)-5alpha-dinosteran-29-ol. The further reduction of the mesylate of this isomer secured (20R,23S,24R)-5alpha-dinosterane (2a). The application of the same sequence of reactions using methyl (3R)-3,4-dimethylpentanoate led principally to (20R,23R,24S)-5alpha-dinosterane (2d). The alkylation of (20S)-20-(iodomethyl)-4alpha-methyl-5alpha-pregnane with methyl (2zeta)-3,4-dimethyl-2-pentanoate and a subsequent reduction of the ester provided a separable mixture of (20R,23R)- and (20R,23S)-5alpha-dinoster-24-(28)-en-29-ol in a 2.4:1 ratio. The conversion of (20R,23R)-5alpha-dinoster-24(28)-en-29-ol to the corresponding tert-butyldimethylsilyl ether, reduction of the DELTA24(28) bond with hydrogen over platinum oxide, and deprotection gave principally (20R,23R,24R)-5alpha-dinosteran-29-ol. The further reduction of this alcohol provided (20R,23R,24R)-5alpha-dinosterane (2b). The application of the same sequence of reactions to (20R,23S)-5alpha-dinoster-24(28)-en-29-ol provided (20R,23S,24S)-5alpha-dinosterane (2c). Diastereoselectivity at the C-23 position in these ester alkylations was examined as a function of stereochemistry at both the C-20 and C-24 positions.

  DOI：

  10.1021/jo00064a039
• 作为产物：
  描述：

  methyl 4-methyl-2-pentenoate 、 乙基溴化镁 在 tetrakis(acetonitrile)copper(I)tetrafluoroborate 、 C₄₄H₅₂FeP₂ 作用下， 以 二氯甲烷 、 甲基叔丁基醚 为溶剂， 以86%的产率得到methyl (3R)-3-ethyl-4-methylpentanoate
  参考文献：
  名称：

  手性尿素型胺：实用合成，配体发展和不对称催化。

  摘要：

  乌吉胺已成为具有中心/平面手性的手性配体设计的一种优先的手性骨架，这种配体在各种不对称催化中已显示出巨大的成功。但是，目前获得对映纯Ugi胺非常繁琐，并且在很大程度上取决于光学分辨率，这在一定程度上阻碍了其实际应用。在本文中，我们介绍了通过Ir催化的级联烯丙基化/ 2-氮杂-Cope重排，然后进行氨基交换和Pd / C催化的一锅加氢/还原反应，轻松地不对称合成带有长碳链的富含对映体的Ugi型胺胺化。该方案很容易扩大规模，并且已在20 g规模的（S来自市售试剂的（-Ugi-type）尿素，> ee> 99％，总收率> 70％，分四个步骤进行一次硅胶短柱纯化。（S，R p）-PPFA型和（S，R p）-Josiphos型配体，很容易从获得的Ugi型胺制备，在几种Cu（I）催化下表现出更高或相当的不对称诱导和催化功效不对称反应，表明易于获得的Ugi型胺在配体/催化剂设计中的应用潜力很大。

  DOI：

  10.1021/acscatal.0c04077

文献信息

• Cu(I) Tol-BINAP-Catalyzed Enantioselective Michael Reactions of Grignard Reagents and Unsaturated Esters
  作者：Shun-Yi Wang、Shun-Jun Ji、Teck-Peng Loh

  DOI：10.1021/ja0666046

  日期：2007.1.1

  A highly efficient regio- and enantioselective catalytic asymmetric addition of Grignard regeants to α,β-unsaturated esters promoted by the CuI-Tol-BINAP system is described.

  描述了由 CuI-Tol-BINAP 系统促进的格氏试剂向 α,β-不饱和酯的高效区域和对映选择性催化不对称加成。