ethyl 13-fluoro-2-isopropyliden-5,9,14-trimethyl-19-(trimethylsilyl)nonadeca-5(E),9(E),13(Z),17(Z)-tetraenoate | 255845-28-4

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: ethyl 13-fluoro-2-isopropyliden-5,9,14-trimethyl-19-(trimethylsilyl)nonadeca-5(E),9(E),13(Z),17(Z)-tetraenoate
• 英文别名: ethyl (5E,9E,13Z,17Z)-13-fluoro-5,9,14-trimethyl-2-propan-2-ylidene-19-trimethylsilylnonadeca-5,9,13,17-tetraenoate
• CAS: 255845-28-4
• 化学式: C₃₀H₅₁FO₂Si
• 分子量: 490.818
• InChiKey: ZMPJCSMWAYHETF-LWVGTZCGSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  10.04
• 重原子数：
  34
• 可旋转键数：
  17
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.63
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为反应物：
  描述：

  甲基锂 、 ethyl 13-fluoro-2-isopropyliden-5,9,14-trimethyl-19-(trimethylsilyl)nonadeca-5(E),9(E),13(Z),17(Z)-tetraenoate 以 乙醚 为溶剂， 以72%的产率得到14-fluoro-3-isopropyliden-2,6,10,15-tetramethyl-20-(trimethylsilyl)eicosa-6(E),10(E),14(Z),18(Z)-tetraen-2-ol
  参考文献：
  名称：

  The Fluorine Atom as a Cation-Stabilizing Auxiliary in Biomimetic Polyene Cyclizations:  Total Synthesis of dl-Dammarenediol¹

  摘要：

  Dammarenediols I (1a) and II (1b) were prepared by an efficient nonenzymatic biomimetic polyene tetracyclization route. The cyclization substrate, pentaenol 3, contains a tetramethylallylic alcohol initiator, an allyltrimethylsilane terminating group, and a fluorine atom at pro-C-13 to serve as a cation-stabilizing (C-S) auxiliary controlling the regiochemistry of the C/D ring juncture. The synthesis of 3 employed lithium-halogen exchange to create alcohols 10 and 19. The Z-fluoroalkene in 3 was introduced stereoselectively via the Trost palladium-catalyzed alkylation of allylic acetate 11 (Z/E: 4.6/1). The cyclization of 3 was most efficient (62% isolated yield) when it was added as a dilute solution in dichloromethane to trifluoroacetic acid at -45 degrees C to afford tetracyclic fluoro diene 24 possessing the trans-anti-trans-anti-trans ring stereochemistry of the dammaranes. Replacement of the fluorine atom of 24 with hydrogen with complete retention of configuration was accomplished using the Ohsawa-Oishi reagent (Na/K alloy and crown ether). Wacker oxidation of the resulting hydrocarbon provided ketone 28, which after ketalization was ozonolyzed with a reductive workup to give the SP-alcohol 30. Ketal hydrolysis followed by Grignard reaction with isopentenylmagnesium bromide afforded the dammarenediols (1/3, 1a/1b).

  DOI：

  10.1021/jo991196s
• 作为产物：
  描述：

  2-fluoro-3-methyl-8-(trimethylsilyl)octa-1,6(Z)-dien-3-yl acetate 在 2,6-二甲基吡啶 、 2,2'-联吡啶 、 sodium hydroxide 、 sodium tetrahydroborate 、 potassium tert-butylate 、 叔丁基锂 、 三溴化磷 、 sodium hydride 、 sodium iodide 、 lithium bromide 、 lithium diisopropyl amide 作用下， 以 四氢呋喃 、 甲醇 、 六甲基磷酰三胺 、 乙醚 、 丙酮 为溶剂， 反应 78.58h， 生成 ethyl 13-fluoro-2-isopropyliden-5,9,14-trimethyl-19-(trimethylsilyl)nonadeca-5(E),9(E),13(Z),17(Z)-tetraenoate
  参考文献：
  名称：

  The Fluorine Atom as a Cation-Stabilizing Auxiliary in Biomimetic Polyene Cyclizations:  Total Synthesis of dl-Dammarenediol¹

  摘要：

  Dammarenediols I (1a) and II (1b) were prepared by an efficient nonenzymatic biomimetic polyene tetracyclization route. The cyclization substrate, pentaenol 3, contains a tetramethylallylic alcohol initiator, an allyltrimethylsilane terminating group, and a fluorine atom at pro-C-13 to serve as a cation-stabilizing (C-S) auxiliary controlling the regiochemistry of the C/D ring juncture. The synthesis of 3 employed lithium-halogen exchange to create alcohols 10 and 19. The Z-fluoroalkene in 3 was introduced stereoselectively via the Trost palladium-catalyzed alkylation of allylic acetate 11 (Z/E: 4.6/1). The cyclization of 3 was most efficient (62% isolated yield) when it was added as a dilute solution in dichloromethane to trifluoroacetic acid at -45 degrees C to afford tetracyclic fluoro diene 24 possessing the trans-anti-trans-anti-trans ring stereochemistry of the dammaranes. Replacement of the fluorine atom of 24 with hydrogen with complete retention of configuration was accomplished using the Ohsawa-Oishi reagent (Na/K alloy and crown ether). Wacker oxidation of the resulting hydrocarbon provided ketone 28, which after ketalization was ozonolyzed with a reductive workup to give the SP-alcohol 30. Ketal hydrolysis followed by Grignard reaction with isopentenylmagnesium bromide afforded the dammarenediols (1/3, 1a/1b).

  DOI：

  10.1021/jo991196s